The promoter is found in prokaryotes. Promoter (molecular genetics). Promoter region prediction
Transcription is the synthesis of RNA on a DNA template. In prokaryotes, the synthesis of all three types of RNA is catalyzed by one complex protein complex - RNA polymerase.
The synthesis of mRNA begins with the discovery by RNA polymerase of a special region in the DNA molecule, which indicates the place where transcription begins - promoter After binding to the promoter, RNA polymerase unwinds the adjacent turn of the DNA helix. Two DNA strands diverge at this point, and on one of them the enzyme synthesizes mRNA. The assembly of ribonucleotides into a chain occurs in compliance with their complementarity to DNA nucleotides, and also antiparallel with respect to the DNA template strand. RNA polymerase is capable of assembling a polynucleotide only from the 5" end to the 3" end; only one of the two DNA strands can serve as a template for transcription, namely the one facing the enzyme with its 3" end (3" → 5") Such a chain is called codogenic.
Terminator- this is the area where further growth of the RNA chain stops and it is released from the DNA template. RNA polymerase also separates from the DNA, which restores its double-stranded structure.
A fragment of a DNA molecule, including a promoter, a transcribed sequence and a terminator, forms a transcription unit - transcripton.
Operon regulation (i.e., regulation at the transcriptional level) is the main mechanism for regulating gene activity in prokaryotes and bacteriophages.
Operon - a section of genetic material, the transcription of which is carried out per RNA molecule under the control of a repressor protein.
An operon consists of closely linked structural genes encoding proteins (enzymes) that carry out successive stages of the biosynthesis of a metabolite. Each operon contains: a promoter, an operator, and a terminator.
Operator- nucleotide sequence that binds repressor protein and negatively regulating transcription neighboring gene. The operator is located between the promoter and structural genes. It may be associated with a special protein - a repressor, which prevents RNA polymerase from moving along the DNA chain and prevents the synthesis of enzymes. Thus, genes can be turned on and off depending on the presence of corresponding repressor proteins in the cell.
Repressor- a regulatory protein that suppresses the transcription of genes of the operon it regulates as a result of binding to the operator (regulatory site of the operon). This leads to the cessation of the synthesis of the corresponding mRNA and, consequently, of the enzymes encoded by the operon. The repressor is synthesized under the control of the gene regulator in the amount of 10 to 20 molecules per cell in the form of active, i.e., capable of directly binding to the operator, or inactive forms. The formation of an active repressor is characteristic of inducible enzymes, the synthesis of which begins only when specific low-molecular substances - inducers - enter the cell . Inductor- a small effector molecule that binds to a regulatory protein, or a physical factor (light, temperature) that stimulates the expression of genes that are in an inactive state.
The promoter includes a number of motifs important for its recognition by RNA polymerase, in particular the so-called sequences -10 and -35. The promoter is asymmetric, which allows RNA polymerase to begin transcription in the correct direction and indicates which of the two DNA strands will serve as a template for RNA synthesis.
The promoter region within the operon may partially overlap or not overlap at all with the operator region of the cistron (gene).
The promoter under which the RNA-coding DNA region is located plays a decisive role in the intensity of expression of this gene in each specific cell type. Promoter activation is determined by the presence of a different set of transcription factors in each cell type
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Synonyms:See what a “Promoter” is in other dictionaries:
Accelerator, activator Dictionary of Russian synonyms. promoter noun, number of synonyms: 2 activator (9) ... Synonym dictionary
PROMOTER, in chemistry, a substance used in small quantities together with a catalyst to increase the activity of the CATALYST. For example, in the HABER PROCESS, an iron catalyst is used to accelerate the reaction of combining hydrogen with nitrogen under... ... Scientific and technical encyclopedic dictionary
A, m. (German: Promotor... Dictionary of foreign words of the Russian language
Promoter- the sequence of nucleotides in a DNA molecule responsible for the beginning of transcription... Source: Procedure and organization of control over food products obtained from/or using raw materials of plant origin that have genetic... ... Official terminology
promoter- The sequence of the DNA molecule, the site of initiation of the transcription process Topics of biotechnology EN promoter ... Technical Translator's Guide
promoter- PROMOTER, PROMOTER a, m. promoteur m. German Promotor lat. promote promote. unit Initiator, instigator. By the end of May we will leave, there is no real plan, and although Natalie has calmed down, I am the main promoter of a long date on the Liman... ... Historical Dictionary of Gallicisms of the Russian Language
promoter- Promotor (Promoter) Promoter, activating agent A substance, the addition of which is aimed at enhancing a certain property of a substance or material. For example, in catalysis, a promoter increases the activity and selectivity of the catalyst, and sometimes... ... Explanatory English-Russian dictionary on nanotechnology. - M.
Promoter (promotor) promoter. The region of a DNA molecule to which RNA polymerase molecules attach
promoter- water repellent; industry activator; promoter A substance applied to the surface of the body to support droplet condensation (by creating a hydrophobic surface layer) ... Polytechnic terminological explanatory dictionary
promoter- promoter (promotor) natkhnennik, kerivnik, patron... A dictionary of old and unlived words
Promoter-regulatory sequence of the 5' region of the gene, which determines the site of attachment of RNA polymerase to DNA. The promoter contains two sequences that play an important role in initiation: the TATA box and the CCAAT domain. The promoter tells RNA polymerase where to start synthesis.
102 question. Explain the concepts: transcript and transcriptome.
Transcript– an RNA molecule formed as a result of transcription of a section of DNA
Transcripton-the totality of all transcripts synthesized by one cell, includes mRNA and non-coding RNA
Question: What molecules are synthesized by RNA polymerase I?
Synthesizes 5.8srRNA, 18srRNA, 28srRNA
responsible for the synthesis of large rRNAs, it is localized in the nucleolus.
Question: What molecules are synthesized by RNA polymerase II?
Synthesizes mRNA, snRNA(low-nuclear), miRNA, miRNA(low-interfering),
mRNA, it is localized in the cytoplasm
Question: What molecules are synthesized by RNA polymerase III.
Synthesizes 5sRNA, tRNA, part of snRNA, small rRNA
Question: What does the transcription mechanism boil down to (RNA synthesis on a DNA template).
As a result of transcription, a primary transcriptiRNA is formed.
Question 107: What is called RNA processing? Name what individual processes it consists of.
The process of mRNA maturation is called processing. Capping, polyadenylation, splicing
Question: What is the splicing reaction of RNA transcripts? The role of the splicingosome in this process.
Splicing- This is the cutting of introns from an mRNA molecule and stitching of exons using ligase enzymes.
The established macromolecular process involves a large number of macromolecules. The macromolecular structure is carried out (splicingosome->small nuclear RNA). snRNAs recognize the boundary between exons and introns and bind to them.
Question 109: When does capping of the 5′ end of RNA in eukaryotes occur and what does it mean? Transcripts of which RNA polymerases are subject to capping.
Immediately after transcription. A methylated guanosine residue is attached to the 5" end of the mRNA; this structure is called a cap. The cap facilitates the binding of mRNA to the ribosome in the cytoplasm.
Only RNA polymerase II transcripts
Question: List all provisions of the significance of mRNA capping.
Ensures the efficiency of further transcription.
Protects the transcript from degradation by 5’-exonucleases (5’-5’ bonds)
A way to further the process: stimulates 3'-polyadenylation and splicing.
Required for export of mRNA from the nucleus
Provides binding of mRNA to the ribosome in the cytoplasm
111.What is polyadenylation of the 3′ end of mRNA. What role does this process play? Transcripts of which RNA polymerases undergo this process.
Polyadenylation– from 100 to 200 adenyl nucleotides are added to the 3" end of the mRNA molecule. A poly-A region is formed. This region stabilizes the mRNA molecule and promotes its release from the nucleus into the cytoplasm.
RNA transcripts-polymerase II
What is alternative splicing? What biological significance does this form of splicing have?
alternative splicing is a form of splicing in which the joining of exons during mRNA maturation occurs in different combinations. In this case, the order of the exons is not violated. Splicing ensures that genes encode different proteins, which is a mechanism of protein diversity in eukaryotes (more than 70% of human genes undergo alternative splicing).
To carry out correct transcription, two types of regulatory elements are required. Regulatory elements of the first type are called cis-regulators. They are specific DNA sequences on a given chromosome. Cis-regulators act only on nearby genes. The second type is called trans-regulators. These are soluble molecules (including proteins and RNA) that are produced by one gene and interact with other genes on the same chromosome or on other chromosomes. If we turn to gene induction in lac-operon E.coli, then we can recall that the repressor gene produces a repressor protein that interacts with the operator sequence for genes lac-operon. In this case the operator is cis-a regulatory element, since it only controls lac- operon of its own chromosome. (A mutant operator sequence on another chromosome may or may not attach a repressor protein.) A repressor protein, in contrast, is trance-regulator. since it is produced by one chromosome and binds to cis-regulatory operator on another chromosome (Fig. 12.5).
Two types are found in eukaryotic genes encoding mRNA cis-regulatory DNA sequences – promoters and enhancers (“amplifiers”). Promoters usually located immediately before the site where it begins
Gilbert s. Developmental biology: in 3 volumes. T. 2: Transl. From English – M.: Mir, 1994. – 235 p.
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Rice. 12.5. Scheme of differential gene regulation in E. coli; shown cis- And trance-regulatory elements. In wild-type cells, the inducible state is characterized by the fact that the RNA for β-galactosidase is not transcribed until lactose is present. In the absence of lactose, the repressor protein (R) encoded by the gene i, joins the operator’s website ( O), thereby inhibiting transcription by RNA polymerase from the promoter ( p). If lactose is present, it binds to the repressor protein, as a result the repressor cannot bind to DNA and transcription continues. The soluble nature of this repressor was demonstrated in experiments on mutants E. Coli. When haploid bacterial cells carrying the gene i – , become partially diploid with the gene i wild type ( i + ), a wild-type repressor is synthesized, which is capable of making the original ß-galactosidase gene inducible. This repressor protein is trance-regulatory element. The promoter and operator sequences are cis-regulatory elements. |
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Rice. 12.6. A typical promoter for a eukaryotic protein-coding gene. The presented gene contains a TATA box and three 5" promoter elements. Examples of such 5' elements are presented in the lower part of the figure. (After Maniatis et al., 1987.) |
transcription, and are approximately 100 base pairs in length. The promoter region is required for the binding of RNA polymerase II and accurate initiation of transcription. The enhancer activates promoter utilization by controlling the efficiency and rate of transcription from that particular promoter. Enhancers activate only those lying in cis-position of promoters (i.e. promoters on the same chromosome), but they can function over long distances. In addition, they can be located not only on the 5" side of the gene, but also on another DNA strand (Maniatis et al., 1987).
The promoters of genes that transcribe relatively large amounts of mRNA have similar structures. They contain the sequence AΤA (sometimes called TATA box or Goldberg-Hogness box), located at a distance of approximately 30 base pairs from the 5" side of the site where transcription begins, and one or more anterior promoter elements, lying even further on the 5" side. The upstream promoter element is usually a variation of the CAAT sequence, but other promoter elements have been identified (Grosschedl and Birnstiel, 1980; McKnight and Tjian, 1986) (Fig. 12.6).
For the first time, the β-globin gene promoter was studied in experiments to test the specific transcription of cloned DNA. Cloned genes can be transcribed correctly when they are introduced into the nuclei of frog oocytes or fibroblasts or when they are incubated with purified RNA polymerase in the presence of supernatant nucleotides (Wasylyk et al., 1980). Once transcription of a gene has been confirmed, restriction enzymes are used to produce specific divisions in that gene or surrounding regions. It can then be determined whether the modified gene continues to be transcribed correctly. The results of these studies showed that the first 109 base pairs preceding the cap site are sufficient for maximum transcription of the ß-globin gene (Grosveld et al., 1982; Dierks et al., 1983).
Other researchers have clarified this conclusion by cloning a region of the mouse globin gene from the 106th base pair upstream (from the 5" side) of the transcription start (position -106) up to the 475th base pair (position +475) in the first exon (Myers et al., 1986). These clones were subjected to in vitro mutagenesis to introduce
As a launching pad for the beginning of specific, or meaningful, transcription. In prokaryotes, the promoter includes a number of motifs important for recognition by RNA polymerase, in particular the so-called sequences -10 and -35. The promoter is asymmetric, which allows RNA polymerase to begin transcription in the correct direction and indicates which of the two DNA strands will serve as a template for RNA synthesis.
The promoter region within the operon may partially overlap or not overlap at all with the operator region of the cistron (gene).
The promoter under which the RNA-coding DNA region is located plays a decisive role in the intensity of expression of this gene in each specific cell type. Promoter activation is determined by the presence of a different set of transcription factors in each cell type.
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Notes
Literature
- Leighton Core, André Martins, Charles Danko, Colin Waters, Adam Siepel, and John Lis. . Nature Genetics, November 2014 DOI: 10.1038/ng.3142
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An excerpt characterizing the Promoter
“I’m very glad to see you, go to where they gathered and wait for me.” - The Emperor went into the office. Prince Pyotr Mikhailovich Volkonsky, Baron Stein, followed him, and the doors closed behind them. Prince Andrei, using the permission of the sovereign, went with Paulucci, whom he knew back in Turkey, into the living room where the council was meeting.Prince Pyotr Mikhailovich Volkonsky held the position of chief of staff of the sovereign. Volkonsky left the office and, bringing cards into the living room and laying them out on the table, conveyed the questions on which he wanted to hear the opinions of the assembled gentlemen. The fact was that during the night news was received (later turned out to be false) about the movement of the French around the Drissa camp.
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