Methods of molecular biology and molecular biotechnology. Biochemistry and molecular biology - where to study? Profession in faces

(Molekular biologe/-biologin)

Type
Profession after graduation
Salary
3667-5623 € per month

Molecular biologists study molecular processes as the basis of all life processes. Based on the results obtained, they develop concepts for the use of biochemical processes, for example in medical research and diagnostics or in biotechnology. In addition, they may be involved in pharmaceutical product manufacturing, product development, quality assurance, or pharmaceutical consulting.

Responsibilities of a Molecular Biologist

Molecular biologists can work in different fields. For example, they concern the use of research results for production in areas such as genetic engineering, protein chemistry or pharmacology (drug discovery). In the chemical and pharmaceutical industries, they facilitate the transfer of newly developed products from research into production, product marketing and user advice.

In scientific research, molecular biologists study the chemical physical properties organic compounds, as well as chemical processes (in the field of cellular metabolism) in living organisms and publish research results. In higher educational institutions they teach students, prepare for lectures and seminars, check written work and administer examinations. Independent scientific activity is possible only after obtaining a master's and doctoral degree.

Where Do Molecular Biologists Work?

Molecular biologists find work, such as

in research institutes, e.g. in the fields of science and medicine
in higher education institutions
in the chemical-pharmaceutical industry
in departments of environmental protection

Molecular Biologist Salary

The salary level received by Molecular Biologists in Germany is

from 3667€ to 5623€ per month

(according to various statistical offices and employment services in Germany)

Tasks and Responsibilities of a Molecular Biologist in Detail

What is the essence of the profession Molecular Biologist

Molecular biologists study molecular processes as the basis of all life processes. Based on the results obtained, they develop concepts for the use of biochemical processes, for example in medical research and diagnostics or in biotechnology. In addition, they may be involved in pharmaceutical product manufacturing, product development, quality assurance, or pharmaceutical consulting.

Vocation Molecular Biology

Molecular biology or molecular genetics deals with the study of the structure and biosynthesis of nucleic acids and the processes involved in the transmission and realization of this information in the form of proteins. This makes it possible to understand painful disorders of these functions and, possibly, to cure them with the help of gene therapy. There are interfaces for biotechnology and genetic engineering that create simple organisms, such as bacteria and yeast, to make substances of pharmacological or commercial interest available on an industrial scale through targeted mutations.

Theory and Practice of Molecular Biology

The chemical-pharmaceutical industry offers numerous areas of employment for molecular biologists. In industrial settings, they analyze biotransformation processes or develop and improve processes for the microbiological production of active ingredients and pharmaceutical intermediates. In addition, they are involved in the transition of newly developed products from research to production. By performing inspection tasks, they ensure that production facilities, equipment, analytical methods and all steps in the production of sensitive products such as pharmaceuticals always meet the required quality standards. In addition, molecular biologists advise users on the use of new products.

Management positions often require a master's program.

Molecular Biologists in Research and Education

In the field of science and research, molecular biologists deal with topics such as the recognition, transport, folding, and codification of proteins in a cell. The results of research, which are the basis for practical applications in various fields, are published and thus made available to other scientists and students. At conferences and congresses, they discuss and present the results of scientific activities. Molecular biologists give lectures and seminars, supervise scientific work and take exams.

Independent scientific activity requires a master's degree and a doctorate.

1. Introduction.

Subject, tasks and methods of molecular biology and genetics. Significance of "classical" genetics and genetics of microorganisms in the development of molecular biology and genetic engineering. The concept of a gene in "classical" and molecular genetics, its evolution. Contribution of genetic engineering methodology to the development of molecular genetics. Applied value of genetic engineering for biotechnology.

2. Molecular bases of heredity.

The concept of a cell, its macromolecular composition. The nature of the genetic material. History of evidence for the genetic function of DNA.

2.1. Various types of nucleic acids. Biological functions of nucleic acids. Chemical structure, spatial structure and physical properties of nucleic acids. Structural features of the genetic material of pro- and eukaryotes. Complementary Watson-Crick base pairs. Genetic code. The history of deciphering the genetic code. The main properties of the code: triplet, code without commas, degeneracy. Features of the code dictionary, families of codons, semantic and "meaningless" codons. Circular DNA molecules and the concept of DNA supercoiling. Topoisomers of DNA and their types. Mechanisms of action of topoisomerases. Bacterial DNA gyrase.

2.2. DNA transcription. Prokaryotic RNA polymerase, its subunit and three-dimensional structures. Variety of sigma factors. Prokaryotic gene promoter, its structural elements. Stages of the transcription cycle. Initiation, formation of an “open complex”, elongation and termination of transcription. transcription attenuation. Regulation of tryptophan operon expression. "Riboswitches". Transcription termination mechanisms. Negative and positive regulation of transcription. lactose operon. Transcriptional regulation in lambda phage development. Principles of DNA recognition by regulatory proteins (CAP protein and lambda phage repressor). Features of transcription in eukaryotes. RNA processing in eukaryotes. Capping, splicing and polyadenylation of transcripts. splicing mechanisms. The role of small nuclear RNA and protein factors. Alternative splicing, examples.

2.3. Broadcast, its stages, the function of ribosomes. Location of ribosomes in the cell. Prokaryotic and eukaryotic types of ribosomes; 70S and 80S ribosomes. Morphology of ribosomes. Division into subparticles (subunits). Codon-dependent binding of aminoacyl-tRNA in the elongation cycle. Codon-anticodon interaction. Participation of the elongation factor EF1 (EF-Tu) in the binding of aminoacyl-tRNA to the ribosome. Elongation factor EF1B (EF-Ts), its function, sequence of reactions with its participation. Antibiotics affecting the stage of codon-dependent binding of aminoacyl-tRNA to the ribosome. Aminoglycoside antibiotics (streptomycin, neomycin, kanamycin, gentamicin, etc.), their mechanism of action. Tetracyclines as inhibitors of aminoacyl-tRNA binding to the ribosome. Broadcast initiation. The main stages of the initiation process. Translation initiation in prokaryotes: initiation factors, initiator codons, RNA 3¢-end of the small ribosomal subunit, and the Shine-Dalgarno sequence in mRNA. Translation initiation in eukaryotes: initiation factors, initiator codons, 5¢-untranslated region and cap-dependent terminal initiation. "Internal" cap-independent initiation in eukaryotes. Transpeptidation. Transpeptidation inhibitors: chloramphenicol, lincomycin, amicetin, streptogramins, anisomycin. Translocation. Involvement of elongation factor EF2 (EF-G) and GTP. Translocation inhibitors: fusidic acid, viomycin, their mechanisms of action. Translation termination. Termination codons. Protein termination factors of prokaryotes and eukaryotes; two classes of termination factors and mechanisms of their action. Regulation of translation in prokaryotes.

2.4. DNA replication and its genetic control. Polymerases involved in replication, their characteristics enzymatic activities. DNA fidelity. The role of steric interactions between DNA base pairs during replication. E. coli polymerases I, II, and III. Polymerase III subunits. Replication fork, "leading" and "lagging" threads during replication. Fragments of the Okazaki. Complex of proteins in the replication fork. Regulation of replication initiation in E. coli. Termination of replication in bacteria. Features of the regulation of plasmid replication. Bidirectional and rolling ring replication.

2.5. Recombination, its types and models. General or homologous recombination. Double-strand breaks in DNA that initiate recombination. The role of recombination in post-replication repair of double-strand breaks. Holliday structure in the recombination model. Enzymology of general recombination in E. coli. RecBCD complex. Reca protein. The role of recombination in ensuring DNA synthesis in DNA damage interrupting replication. recombination in eukaryotes. Recombination enzymes in eukaryotes. Site-specific recombination. Differences in the molecular mechanisms of general and site-specific recombination. Classification of recombinases. Types of chromosomal rearrangements carried out during site-specific recombination. Regulatory role of site-specific recombination in bacteria. Construction of multicellular eukaryotic chromosomes using the site-specific phage recombination system.

2.6. DNA repair. Classification of types of reparation. Direct repair of thymine dimers and methylated guanine. Cutting out bases. Glycosylases. The mechanism of repair of unpaired nucleotides (mismatch repair). Selection of the DNA strand to be repaired. SOS repair. Properties of DNA polymerases involved in SOS repair in prokaryotes and eukaryotes. The concept of "adaptive mutations" in bacteria. Repair of double-strand breaks: homologous post-replicative recombination and association of non-homologous ends of the DNA molecule. The relationship between the processes of replication, recombination and reparation.

3. Mutation process.

The role of biochemical mutants in the formation of the theory of one gene - one enzyme. Mutation classification. Point mutations and chromosomal rearrangements, the mechanism of their formation. Spontaneous and induced mutagenesis. Classification of mutagens. Molecular mechanism of mutagenesis. Relationship between mutagenesis and repair. Identification and selection of mutants. Suppression: intragenic, intergenic and phenotypic.

4. Extrachromosomal genetic elements.

Plasmids, their structure and classification. Sex factor F, its structure and life cycle. The role of factor F in the mobilization of chromosome transfer. Formation of Hfr and F donors. Mechanism of conjugation. Bacteriophages, their structure and life cycle. Virulent and temperate bacteriophages. Lysogeny and transduction. General and specific transduction. Migrating genetic elements: transposons and IS sequences, their role in genetic metabolism. DNA -transposons in the genomes of prokaryotes and eukaryotes IS-sequences of bacteria, their structure IS-sequences as a component of the F-factor of bacteria, which determines the ability to transfer genetic material during conjugation Transposons of bacteria and eukaryotic organisms Direct non-replicative and replicative mechanisms of transpositions The concept of horizontal transposon transfer and their role in structural rearrangements (ectopic recombination) and in genome evolution.

5. Study of the structure and function of the gene.

Elements of genetic analysis. Cis-trans complementation test. Genetic mapping using conjugation, transduction and transformation. Construction of genetic maps. Fine genetic mapping. Physical analysis of the gene structure. heteroduplex analysis. Restriction analysis. Sequencing methods. polymerase chain reaction. Revealing the function of a gene.

6. Regulation of gene expression. Concepts of operon and regulon. Control at the level of transcription initiation. Promoter, operator and regulatory proteins. Positive and negative control of gene expression. Control at the level of transcription termination. Catabolite-controlled operons: models of lactose, galactose, arabinose and maltose operons. Attenuator-controlled operons: a model of the tryptophan operon. Multivalent regulation of gene expression. Global systems of regulation. Regulatory response to stress. post-transcriptional control. signal transduction. RNA-mediated regulation: small RNAs, sensor RNAs.

7. Fundamentals of genetic engineering. Restriction enzymes and modifications. Isolation and cloning of genes. Vectors for molecular cloning. Principles of construction of recombinant DNA and their introduction into recipient cells. Applied aspects of genetic engineering.

A). Main literature:

1. Watson J., Tooze J., Recombinant DNA: A Brief Course. – M.: Mir, 1986.

2. Genes. – M.: Mir. 1987.

3. Molecular biology: structure and biosynthesis of nucleic acids. / Ed. . - M. Higher school. 1990.

4., - Molecular biotechnology. M. 2002.

5. Spirin ribosomes and protein biosynthesis. - M .: Higher School, 1986.

b). Additional literature:

1. Hesin of the genome. – M.: Science. 1984.

2. Rybchin of genetic engineering. - St. Petersburg: St. Petersburg State Technical University. 1999.

3. Patrushev genes. – M.: Nauka, 2000.

4. Modern microbiology. Prokaryotes (in 2 vols.). – M.: Mir, 2005.

5. M. Singer, P. Berg. Genes and genomes. – M.: Mir, 1998.

6. Shchelkunov engineering. - Novosibirsk: From Sib. Univ., 2004.

7. Stepanov biology. Structure and functions of proteins. - M.: V. Sh., 1996.

A molecular biologist is a medical researcher whose mission is nothing less than saving humanity from dangerous diseases. Among such diseases, for example, oncology, which today has become one of the main causes of death in the world, is only slightly inferior to the leader - cardiovascular diseases. New methods of early diagnosis of oncology, prevention and treatment of cancer - a priority modern medicine. Molecular biologists in the field of oncology develop antibodies and recombinant (genetically engineered) proteins for early diagnosis or targeted drug delivery in the body. Specialists in this field use the latest achievements of science and technology to create new organisms and organic substances in order to further use in research and clinical activities. Among the methods used by molecular biologists are cloning, transfection, infection, polymerase chain reaction, gene sequencing, and others. One of the companies interested in molecular biologists in Russia is PrimeBioMed LLC. The organization is engaged in the production of antibodies-reagents for diagnostics oncological diseases. Such antibodies are mainly used to determine the type of tumor, its origin and malignancy, that is, the ability to metastasize (spread to other parts of the body). Antibodies are applied to thin sections of the examined tissue, after which they bind in cells to certain proteins - markers that are present in tumor cells, but absent in healthy ones and vice versa. Depending on the results of the study, further treatment is prescribed. PrimeBioMed's clients include not only medical, but also scientific institutions, since antibodies can also be used to solve research problems. In such cases, unique antibodies capable of binding to the studied protein can be produced for a specific task by special order. Another promising direction of the company's research is targeted (targeted) delivery of drugs in the body. In this case, antibodies are used as transport: with their help, drugs are delivered directly to the affected organs. Thus, the treatment becomes more effective and has fewer negative consequences for the body than, for example, chemotherapy, which affects not only cancer cells, but also other cells. The profession of a molecular biologist is expected to become more and more in demand in the coming decades: with an increase in the average life expectancy of a person, the number of oncological diseases will increase. Early detection of tumors and innovative methods of treatment with the help of substances obtained by molecular biologists will save lives and improve its quality for a huge number of people.

Basic vocational education

Percentages reflect the distribution of specialists with a certain level of education in the labor market. Key specializations for mastering the profession are marked in green.

Abilities and skills

Ability to handle reagents, samples, must be able to work with small objects
Ability to work with large volumes of information
Ability to work with hands

Interests and preferences

Eagerness to learn something new
Ability to work in multitasking mode (it is necessary to monitor the progress of several reactions and processes at the same time)
Accuracy
Responsibility (you can not leave the work "for tomorrow", as the samples may be damaged)
scrupulousness
industriousness
Mindfulness (it is necessary to monitor microprocesses)

Profession in faces

Maria Shitova

Daria Samoilova

Alexey Grachev

Molecular biology in the field of oncology is a promising professional area, since the fight against cancer is one of the priority tasks of world medicine.

Molecular biologists are in demand in many areas due to the active development of science, biotechnological and innovative enterprises. To date, there is a small shortage of specialists, especially those with some experience in their specialty. Until now, a fairly large number of graduates continue to go to work abroad. Opportunities are starting to emerge effective work in the field of biotechnology in Russia, but it is too early to talk about mass character.

The work of a molecular biologist involves the active participation of a specialist in scientific activities, which becomes a mechanism for career advancement. Development in the profession is possible through participation in scientific projects and conferences, perhaps through the development of related fields of knowledge. Also, in the future, academic development is possible from a junior researcher through a senior researcher to a leading researcher, professor and / or head of department / laboratory.

interview

Pirogov Sergey - a participant in the preparation for the Olympiad in biology, organized by "Elephant and Giraffe" in 2012.
Winner of the International Universiade in Biology
The winner of the Olympiad "Lomonosov"
Winner of the regional stage of the All-Russian Olympiad in Biology in 2012
Studying at Moscow State University. M.V. Lomonosov at the Faculty of Biology: Department of Molecular Biology, 6th year student. Works in the Laboratory of Biochemical Genetics of Animals of the Institute of Molecular Genetics.

- Seryozha, if readers have questions, will they be able to ask you?

Yes, of course, you can ask questions at least immediately. In this field:

Click here to ask a question.

- Let's start with school, didn't you have a super-cool school?

I studied at a very weak Moscow school, such an average secondary school. True, we had a wonderful teacher at the Moscow Art Theater, thanks to whom we had a largely nominal "art history" orientation of the school.

- What about biology?

Our biology teacher was a very elderly, deaf and sharp woman, whom everyone was afraid of. But love for her subject did not add. I have been passionate about biology since childhood, from the age of five. I read everything myself, mainly being carried away by anatomy and zoology. So school subjects existed in parallel with my own interests. The Olympics changed everything.

- Tell me more about it.

In the 7th grade, I took part in the municipal stage for the first time (of course, in almost all subjects at once, since I was the only student whom the teachers had reason to send). And he won in biology. Then the school treated this as a funny, but not very interesting fact.

- Did it help you in school?

I remember that despite my brilliant studies, I often received B from a biology teacher with nit-picking like "in the drawing of a section of an onion, the roots should be painted brown, not gray." It was all pretty depressing. In the 8th grade, I again went to the Olympiad, but for some reason I was not sent in biology. But he became a winner and prize-winner in other subjects.

- What happened in 9th grade?

In the 9th grade, I did not go to the district stage. It was there that I unexpectedly scored a weak, borderline score, which nevertheless turned out to be passing to the regional stage. This had a powerful motivating force - the realization of how much I don’t know and how many people who know all this (how many such people on a national scale I was even afraid to imagine).

- Tell us how you prepared.

Intense self-study, forays into bookstores, and thousands of last year's assignments had a healing effect. I scored one of the highest scores for theory (which was also completely unexpected for me), passed to practical stage...and failed it. At that time, I did not even know about the existence of the practical stage.

- Did the Olympics influence you?

My life has changed radically. I learned about many other Olympiads, especially I fell in love with the SBO. Subsequently, he showed good results on many, won some, thanks to Lomonosovskaya he received the right to enter without exams. At the same time, I won Olympiads in the history of art, to which I still breathe unevenly. True, he was not friends with practical tours. In the 11th grade, I still reached final stage, but Fortune was not favorable and this time I did not have time to fill in the answer matrix of the theoretical stage. But this made it possible not to worry too much about the practical.

- Have you met many Olympiads?

Yes, I still think that I was very lucky with the circle of my peers, who greatly expanded my horizons. The other side of the Olympiads, in addition to the motivation to study the subject more harmoniously, was acquaintance with the Olympiads. Already at that time, I noticed that horizontal communication is sometimes more useful than vertical communication - with teachers at the training camp.

- How did you enter the university? Did you choose a faculty?

After the 11th grade, I entered the Faculty of Biology of Moscow State University. Just the majority of my then comrades made a choice in favor of the FBB, but here the primary role was played by the fact that I did not become the winner of the All-Russian. So I would have to take an internal exam in mathematics, and in it, especially at school - I fell in love with the higher one much more - I was not strong. And there was very poor preparation at school (we were not even prepared for almost the entire C part). In terms of interests, even then I guessed that, in the end, you can come to any result, regardless of the place of admission. Subsequently, it turned out that there are many FBB graduates who switched to predominantly wet biology, and vice versa - many good bioinformaticians started out as amateurs. Although at that moment it seemed to me that the contingent at the biological faculty would be unlike the FBBshny one. In this I was certainly wrong.

Did you know?

Interesting

Did you know?

Interesting

In the camp Elephant and Giraffe there are shifts in biochemistry and molecular biology, where schoolchildren, together with experienced teachers from Moscow State University, set up experiments and also prepare for Olympiads.

© Interviewed by Reshetov Denis. The photos were kindly provided by Sergey Pirogov.

It can be said that molecular biology studies the manifestations of life on inanimate structures or systems with elementary signs of vital activity (which can be individual biological macromolecules, their complexes or organelles), studying how the key processes that characterize living matter are realized through chemical interactions and transformations.

The separation of molecular biology from biochemistry into an independent field of science is dictated by the fact that its main task is to study the structure and properties of biological macromolecules involved in various processes elucidation of the mechanisms of their interaction. Biochemistry, on the other hand, deals with the study of the actual processes of vital activity, the patterns of their course in a living organism, and the transformations of molecules that accompany these processes. Ultimately, molecular biology tries to answer the question of why this or that process occurs, while biochemistry answers the questions of where and how, from the point of view of chemistry, the process in question occurs.

Story

Molecular biology as a separate area of biochemistry began to take shape in the 1930s. It was then that for a deeper understanding of the phenomenon of life, the need arose for targeted studies at the molecular level of the processes of storage and transmission of hereditary information in living organisms. Then the task of molecular biology was defined in the study of the structure, properties and interaction of nucleic acids and proteins. The term "molecular biology" was first used by the English scientist William Astbury in the context of research related to elucidating the relationship between molecular structure and physical and biological properties fibrillar proteins such as collagen, blood fibrin or muscle contractile proteins.

In the early days of molecular biology, RNA was considered a component of plants and fungi, while DNA was seen as a typical component of animal cells. The first researcher to prove that DNA is found in plants was Andrey Nikolaevich Belozersky, who isolated pea DNA in 1935. This discovery established the fact that DNA is a universal nucleic acid present in plant and animal cells.

A major achievement was the establishment by George Beadle and Edward Tatum of a direct causal relationship between genes and proteins. In their experiments, they exposed neurospore cells ( Neurosporacrassa) X-ray exposure that caused mutations. The results obtained showed that this led to a change in the properties of specific enzymes.

In 1940, Albert Claude isolated cytoplasmic RNA-containing granules from the cytoplasm of animal cells, which were smaller than mitochondria. He called them microsomes. Subsequently, in the study of the structure and properties of the isolated particles, their fundamental role in the process of protein biosynthesis was established. In 1958, at the first symposium dedicated to these particles, it was decided to call these particles ribosomes.

Another important step in the development of molecular biology was the published data of the experiment of Oswald Avery, Colin MacLeod and MacLean McCarthy in 1944, which showed that DNA is the cause of bacterial transformation. This was the first experimental evidence of the role of DNA in the transmission of hereditary information, debunking the earlier idea of the protein nature of genes.

In the early 1950s, Frederick Sanger showed that a protein chain is a unique sequence of amino acid residues. In the late 1950s, Max Perutz and John Kendrew deciphered the spatial structure of the first proteins. Already in 2000, hundreds of thousands of natural amino acid sequences and thousands of spatial structures of proteins were known.

Around the same time, Erwin Chargaff's research allowed him to formulate rules describing the ratio of nitrogenous bases in DNA (the rules say that regardless of species differences in DNA, the amount of guanine is equal to the amount of cytosine, and the amount of adenine is equal to the amount of themin), which later helped to make the greatest a breakthrough in molecular biology and one of the greatest discoveries in biology in general.

This event occurred in 1953 when James Watson and Francis Crick, based on the work of Rosalind Franklin and Maurice Wilkins on X-ray diffraction analysis DNA, established the double-stranded structure of the DNA molecule. This discovery made it possible to answer the fundamental question about the ability of the carrier of hereditary information to self-reproduce and to understand the mechanism of transmission of such information. The same scientists formulated the principle of complementarity of nitrogenous bases, which is of key importance for understanding the mechanism of formation of supramolecular structures. This principle, which is now used to describe all molecular complexes, makes it possible to describe and predict the conditions for the emergence of weak (nonvalent) intermolecular interactions, which determine the possibility of the formation of secondary, tertiary, etc. structures of macromolecules, self-assembly of supramolecular biological systems that determine such a wide variety of molecular structures and their functional sets. Then, in 1953, the scientific journal Journal of Molecular Biology appeared. It was headed by John Kendrew, whose area of scientific interest was the study of the structure of globular proteins (Nobel Prize in 1962, jointly with Max Perutz). A similar Russian-language journal called Molecular Biology was founded in the USSR by V. A. Engelhardt in 1966.

In 1958, Francis Crick formulated the so-called. the central dogma of molecular biology: the idea of the irreversibility of the flow of genetic information from DNA through RNA to proteins according to the scheme DNA → DNA (replication, creation of a copy of DNA), DNA → RNA (transcription, copying of genes), RNA → protein (translation, decoding of information about the structure proteins). This dogma was somewhat corrected in 1970, taking into account the accumulated knowledge, since the phenomenon of reverse transcription was discovered independently by Howard Temin and David Baltimore: an enzyme was discovered - reverse transcriptase, which is responsible for the implementation of reverse transcription - the formation of double-stranded DNA on a single-stranded RNA template, which occurs in oncogenic viruses. It should be noted that the strict necessity of the flow of genetic information from nucleic acids to proteins still remains the basis of molecular biology.

In 1957, Alexander Sergeevich Spirin, together with Andrei Nikolaevich Belozersky, showed that, despite significant differences in the nucleotide composition of DNA from different organisms, the composition of total RNA is similar. Based on these data, they came to the sensational conclusion that the total RNA of a cell cannot act as a carrier of genetic information from DNA to proteins, since it does not correspond to it in its composition. At the same time, they noticed that there is a minor fraction of RNA, which fully corresponds in its nucleotide composition to DNA and which can be a true carrier of genetic information from DNA to proteins. As a result, they predicted the existence of relatively small RNA molecules, which are analogous in structure to individual sections of DNA and act as intermediaries in the transfer of genetic information contained in DNA to the ribosome, where protein molecules are synthesized using this information. In 1961 (S. Brenner, F. Jacob, M. Meselson on the one hand and F. Gros, Francois Jacob and Jacques Monod were the first to experimentally confirm the existence of such molecules - informational (matrix) RNA. At the same time they developed the concept and model of functional units of DNA - an operon, which made it possible to explain exactly how the regulation of gene expression in prokaryotes is carried out. The study of the mechanisms of protein biosynthesis and the principles of the structural organization and operation of molecular machines - ribosomes - made it possible to formulate a postulate describing the movement of genetic information, called the central dogma of molecular biology: DNA - mRNA is a protein.

In 1961 and over the next few years, Heinrich Mattei and Marshall Nirenberg, and then Har Korana and Robert Holly, carried out several works to decipher the genetic code, as a result of which a direct relationship was established between the DNA structure and synthesized proteins and the nucleotide sequence that determines set of amino acids in a protein. Data on the universality of the genetic code were also obtained. The discoveries were marked nobel prize 1968.

For the development of modern ideas about the functions of RNA, the discovery of non-coding RNA, made on the basis of the results of the work of Alexander Sergeevich Spirin together with Andrei Nikolaevich Belozersky in 1958, Charles Brenner with co-authors and Saul Spiegelman in 1961, was decisive. This type of RNA makes up the bulk of cellular RNA. Ribosomal RNAs are primarily non-coding.

Methods for cultivating and hybridizing animal cells have received serious development. In 1963, François Jacob and Sydney Brenner formulated the idea of a replicon, a sequence of inherently replicating genes that explains important aspects of the regulation of gene replication.

In 1967, in the laboratory of A. S. Spirin, it was demonstrated for the first time that the shape of compactly folded RNA determines the morphology of the ribosomal particle.

In 1968, a significant fundamental discovery was made. Okazaki, having discovered DNA fragments of the lagging strand in the study of the replication process, named Okazaki fragments after her, clarified the mechanism of DNA replication.

In 1970, Howard Temin and David Baltimore independently made a significant discovery: an enzyme was discovered - reverse transcriptase, which is responsible for the implementation of reverse transcription - the formation of double-stranded DNA on a single-stranded RNA template, which occurs in oncogenic viruses containing RNA.

Another important achievement of molecular biology was the explanation of the mechanism of mutations at the molecular level. As a result of a series of studies, the main types of mutations were established: duplications, inversions, deletions, translocations and transpositions. This made it possible to consider evolutionary changes from the point of view of gene processes, and made it possible to develop the theory of molecular clocks, which is used in phylogeny.

By the beginning of the 1970s, the basic principles of the functioning of nucleic acids and proteins in a living organism had been formulated. It was found that proteins and nucleic acids in the body are synthesized according to a matrix mechanism, the matrix molecule carries encrypted information about the sequence of amino acids (in a protein) or nucleotides (in a nucleic acid). During replication (doubling of DNA) or transcription (synthesis of mRNA), DNA serves as such a template, during translation (protein synthesis) or reverse transcription - mRNA.

Thus, theoretical prerequisites were created for the development of applied areas of molecular biology, in particular, genetic engineering. In 1972 Paul Berg, Herbert Bauer and Stanley Cohen developed molecular cloning technology. Then they were the first to obtain recombinant DNA in vitro. These outstanding experiments laid the foundations of genetic engineering, and this year is considered the birth date of this scientific direction.

In 1977, Frederick Sanger, and independently Allan Maxum and Walter Gilbert developed various methods determining the primary structure (sequencing) of DNA. The Sanger method, the so-called chain termination method, is the basis of the modern sequencing method. The principle of sequencing is based on the use of labeled bases that act as terminators in a cyclic sequencing reaction. This method has become widespread due to the ability to quickly conduct analysis.

1976 - Frederick. Sanger deciphered the nucleotide sequence of the DNA of the phage φΧ174 with a length of 5375 nucleotide pairs.

1981 - Sickle cell anemia becomes the first genetic disease to be diagnosed by DNA analysis.

1982-1983 the discovery of the catalytic function of RNA in the American laboratories of T. Check and S. Altman changed the existing ideas about the exclusive role of proteins. By analogy with catalytic proteins - enzymes, catalytic RNAs were called ribozymes.

1987 Keri Mullez discovered the polymerase chain reaction, thanks to which it is possible to artificially significantly increase the number of DNA molecules in solution for further work. Today it is one of the most important methods of molecular biology used in the study of hereditary and viral diseases, in the study of genes and in genetic identification and kinship, etc.

In 1990, at the same time, three groups of scientists published a method that made it possible to quickly obtain synthetic functionally active RNAs in the laboratory (artificial ribozymes or molecules that interact with various ligands - aptamers). This method is called "evolution in vitro". And soon after that, in 1991-1993 in the laboratory of A.B. Chetverina was experimentally shown the possibility of existence, growth and amplification of RNA molecules in the form of colonies on solid media.

In 1998, almost simultaneously, Craig Mello and Andrew Fire described the mechanism observed earlier in gene experiments with bacteria and flowers. RNA interference, in which a small double-stranded RNA molecule leads to a specific suppression of gene expression.

The discovery of the mechanism of RNA interference is of great importance. practical value for modern molecular biology. This phenomenon is widely used in scientific experiments as a tool for "turning off", that is, suppressing the expression of individual genes. Of particular interest is the fact that this method allows reversible (temporary) suppression of the activity of the studied genes. Research is underway to apply this phenomenon to the treatment of viral, neoplastic, degenerative and metabolic diseases. It should be noted that in 2002, mutants of polio viruses were discovered that can avoid RNA interference, so more painstaking work is required to develop a truly effective methods treatment based on this phenomenon.

In 1999-2001, several groups of researchers determined the structure of the bacterial ribosome with a resolution of 5.5 to 2.4 angstroms.

Item

The achievements of molecular biology in the knowledge of living nature can hardly be overestimated. Great success has been achieved thanks to a successful research concept: complex biological processes are considered from the standpoint of individual molecular systems, which makes it possible to apply precise physicochemical research methods. It also attracted many great minds from related areas to this area of science: chemistry, physics, cytology, virology, which also had a beneficial effect on the scale and speed of development of scientific knowledge in this area. Such significant discoveries as the determination of the DNA structure, the deciphering of the genetic code, and the artificial directed modification of the genome have made it possible to better understand the specifics of the developmental processes of organisms and successfully solve numerous major fundamental and applied scientific, medical and social tasks, which until recently were considered unsolvable.

The subject of study of molecular biology is mainly proteins, nucleic acids and molecular complexes (molecular machines) based on them and the processes in which they participate.

Nucleic acids are linear polymers consisting of nucleotide units (compounds of a five-membered sugar with a phosphate group at the fifth atom of the cycle and one of the four nitrogenous bases) interconnected by an ester bond of phosphate groups. Thus, nucleic acid is a pentose phosphate polymer with nitrogenous bases as side substituents. Chemical composition RNA chain differs from DNA in that the first consists of a five-membered ribose carbohydrate cycle, while the second consists of a dehydroxylated ribose derivative - deoxyribose. At the same time, these molecules differ dramatically in space, since RNA is a flexible single-stranded molecule, while DNA is a double-stranded molecule.

Proteins are linear polymers, which are chains of alpha-amino acids interconnected by a peptide bond, hence their second name - polypeptides. The composition of natural proteins includes many different amino acid units - in humans up to 20 -, which determines a wide variety of functional properties of these molecules. These or other proteins are involved in almost every process in the body and perform many tasks: they play the role of cellular building material, provide transport of substances and ions, catalyze chemical reactions, this list is very long. Proteins form stable molecular conformations of various levels of organization (secondary and tertiary structures) and molecular complexes, which further expands their functionality. These molecules can have a high specificity for performing certain tasks due to the formation of a complex spatial globular structure. A wide variety of proteins ensures the constant interest of scientists in this kind of molecules.

Modern ideas about the subject of molecular biology are based on a generalization first put forward in 1958 by Francis Crick as the central dogma of molecular biology. Its essence was the assertion that genetic information in living organisms goes through strictly defined stages of implementation: copying from DNA to DNA at the entrance of inheritance, from DNA to RNA, and then from RNA to protein, and the reverse transition is not feasible. This statement was true only in part, therefore, subsequently, the central dogma was corrected with an eye to the newly discovered data.

At the moment, there are several ways to implement the genetic material, representing different sequences for the implementation of the three types of existence of genetic information: DNA, RNA and protein. In nine possible ways of realization, three groups are distinguished: these are three general transformations (general), which are carried out normally in most living organisms; three special transformations (special), carried out in some viruses or in special laboratory conditions; three unknown transformations (unknown), the implementation of which is considered impossible.

Common transformations include the following ways of implementing the genetic code: DNA→DNA (replication), DNA→RNA (transcription), RNA→protein (translation).

To carry out the transfer of hereditary traits, parents need to pass on a full-fledged DNA molecule to their descendants. The process by which an exact copy of the original DNA can be synthesized, and therefore genetic material can be transferred, is called replication. It is carried out by special proteins that unravel the molecule (straighten its section), unwind the double helix and, using DNA polymerase, create an exact copy of the original DNA molecule.

To ensure the life of a cell, it needs to constantly refer to the genetic code embedded in the DNA double helix. However, this molecule is too large and clumsy to be used as a direct source of genetic material for continuous protein synthesis. Therefore, in the course of implementing the information embedded in DNA, there is an intermediary stage: the synthesis of mRNA, which is a small single-stranded molecule complementary to a certain segment of DNA encoding a certain protein. The transcription process is provided by RNA polymerase and transcription factors. The resulting molecule can then be easily delivered to the part of the cell responsible for protein synthesis - the ribosome.

After RNA enters the ribosome, the final stage of the realization of genetic information begins. In this case, the ribosome reads the genetic code from mRNA in triplets called codons and synthesizes the corresponding protein based on the information received.

In the course of special transformations, the genetic code is realized according to the scheme RNA → RNA (replication), RNA → DNA (reverse transcription), DNA → protein (direct translation). Replication of this type is realized in many viruses, where it is carried out by the enzyme RNA-dependent RNA polymerase. Similar enzymes are also found in eukaryotic cells, where they are associated with the process of RNA silencing. Reverse transcription has been found in retroviruses, where it is carried out by the enzyme reverse transcriptase, and in some cases in eukaryotic cells, for example, during telomeric synthesis. Live transmission is carried out only in artificial conditions in an isolated system outside the cell.

Any of the three possible transitions of genetic information from protein to protein, RNA or DNA is considered impossible. The case of the action of prions on proteins, as a result of which a similar prion is formed, could conditionally be attributed to the type of realization of genetic information protein → protein. However, formally it is not such, since it does not affect the amino acid sequence in the protein.

The history of the emergence of the term "central dogma" is curious. Since the word dogma generally means a statement that is not subject to doubt, and the word itself has a clear religious connotation, choosing it as a description of a scientific fact is not entirely legitimate. According to Francis Crick himself, it was his mistake. He wanted to give the theory put forward more significance, to distinguish it from the background of other theories and hypotheses; why he decided to use this majestic, in his opinion, word, not understanding its true meaning. The name, however, stuck.

Molecular biology today

The rapid development of molecular biology, the constant interest in achievements in this field on the part of society, and the objective importance of research have led to the emergence a large number major research centers of molecular biology around the world. Among the largest, the following should be mentioned: the laboratory of molecular biology in Cambridge, the Royal Institute in London - in the UK; institutes of molecular biology in Paris, Marseille and Strasbourg, Pasteur Institute - in France; departments of molecular biology at Harvard University and the Massachusetts Institute of Technology, the University of Berkeley, the California Institute of Technology, the Rockefeller University, the Institute of Public Health in Bethesda - in the USA; the Max Planck institutes, the universities in Göttingen and Munich, the Central Institute for Molecular Biology in Berlin, the institutes in Jena and Halle - in Germany; Karolinska Institute in Stockholm, Sweden.

In Russia, the leading centers in this field are the Institute of Molecular Biology. Institute of Molecular Genetics RAS, Institute of Gene Biology RAS, Institute of Physicochemical Biology named after V.A. A. N. Belozersky Moscow State University. M.V. Lomonosov Institute of Biochemistry. A.N. Bach RAS and the Institute of Protein RAS in Pushchino.

Today, the field of interest of molecular biologists covers a wide range of fundamental scientific issues. As before, the leading role is occupied by the study of the structure of nucleic acids and protein biosynthesis, the study of the structure and functions of various intracellular structures and cell surfaces. Also important areas of research are the study of the mechanisms of reception and signal transmission, the molecular mechanisms of the transport of compounds within the cell and also from the cell to the external environment and back. Among the main directions of scientific research in the field of applied molecular biology, one of the most priority is the problem of the emergence and development of tumors. Also a very important area, which is studied by the section of molecular biology - molecular genetics, is the study of the molecular basis of the occurrence of hereditary diseases, and viral diseases, such as AIDS, as well as the development of methods for their prevention and, possibly, treatment at the gene level. The discoveries and developments of molecular biologists in forensic medicine have found wide application. A real revolution in the field of personal identification was made in the 80s by scientists from Russia, the USA and Great Britain thanks to the development and implementation of the method of "genomic fingerprinting" - the identification of DNA in everyday practice. Research in this area continues to this day. modern methods allow you to identify the person with a probability of error of one billionth of a percent. Already, there is an active development of the project of a genetic passport, which, as expected, will greatly reduce the level of crime.

Methodology

Today, molecular biology has an extensive arsenal of methods to solve the most advanced and most challenging tasks facing scientists.

One of the most common methods in molecular biology is gel electrophoresis, which solves the problem of separating a mixture of macromolecules by size or charge. Almost always, after the separation of macromolecules in the gel, blotting is used, a method that allows you to transfer macromolecules from the gel ( sorb) to the membrane surface for the convenience of further work with them, in particular hybridization. Hybridization - the formation of hybrid DNA from two strands of different nature - a method that plays an important role in fundamental research. It is used to determine complementary segments in different DNA (DNA different types), with its help, new genes are searched for, RNA interference was discovered with its help, and its principle formed the basis of genomic fingerprinting.

An important role in the modern practice of molecular biological research is played by the sequencing method - determining the sequence of nucleotides in nucleic acids and amino acids in proteins.

Modern molecular biology cannot be imagined without the polymerase chain reaction (PCR) method. Thanks to this method, an increase in the number (amplification) of copies of a certain DNA sequence is carried out in order to obtain from one molecule a sufficient amount of a substance for further work with it. A similar result is achieved by molecular cloning technology, in which the required nucleotide sequence is introduced into the DNA of bacteria (living systems), after which the multiplication of bacteria leads to the desired result. This approach is technically much more complicated, but it allows one to simultaneously obtain the result of the expression of the studied nucleotide sequence.

Also, ultracentrifugation methods are widely used in molecular biological research (to separate macromolecules ( large quantities), cells, organelles), electron and fluorescence microscopy methods, spectrophotometric methods, X-ray diffraction analysis, autoradiography, etc.

Thanks to technological progress and scientific research in the field of chemistry, physics, biology and computer science, modern equipment makes it possible to isolate, study and change individual genes and the processes in which they are involved.