Transcription regulation is a set of processes in the cell , through which the control of transcription — RNA synthesis on the DNA template — is carried out as one of the stages of gene expression . Transcriptional activity of a gene can be controlled by more than one mechanism. These mechanisms differ in prokaryotes and eukaryotes .
Transcriptional regulation in eukaryotes
The regulation of transcription in eukaryotes is carried out at two interrelated levels [1] :
- at the level of the apparatus and transcription factors ;
- at the level of chromatin structure.
Regulation at the level of transcription factors
Transcription factors are proteins that have the ability to stimulate or suppress gene transcription when they bind to regulatory regions of DNA. As a rule, transcription factors interact with cofactors — proteins or protein complexes that contribute to stimulation ( coactivators ) or suppression ( corepressors ) of transcription, but not having their own DNA-binding ability. The regulation of transcription at the factor level is carried out at the initiation or elongation stage.
In 2007, it was shown that the promoters of many genes in eukaryotes constantly contain a fully assembled initiator complex that can synthesize short transcripts (20-60 nucleotides ), after which the movement of RNA polymerase II stops [2] [3] [4] . RNA polymerase II is stopped by two negative regulators DSIF ( DRB sensitivity sensitivity factor ) and NELF ( English negative elongation factor ), which are associated with the enzyme . The movement of the transcriptional complex can be restored under the action of the positive PTEFb regulator ( positive transcription elongation factor b ), which phosphorylates repetitive amino acid motifs in the C-terminal domain of RNA polymerase II at the position of Ser -2, as well as DSIF and NELF [1] . Otherwise, termination of transcription eventually occurs with the release of a short RNA product. Thus, controlling the transition from pause to productive elongation is an important way of regulating transcription.
Notes
- 2 1 2 Lee TI , Young RA Transcriptional Regulation and its misregulation in disease. (English) // Cell. - 2013. - Vol. 152, no. 6 - P. 1237-1251. - DOI : 10.1016 / j.cell.2013.02.014 . - PMID 23498934 .
- Ent Guenther MG , Levine SS , Boyer LA , Jaenisch R. , Young RA A chromatin landmark and transcription initiation of most human cells. (English) // Cell. - 2007. - Vol. 130, no. 1 . - p. 77-88. - DOI : 10.1016 / j.cell.2007.05.05.042 . - PMID 17632057 .
- ↑ Muse GW , Gilchrist DA , Nechaev S. , Shah R. , Parker JS , Grissom SF , Zeitlinger J. , Adelman K. RNA polymerase. (English) // Nature genetics. - 2007. - Vol. 39, no. 12 - P. 1507-1511. - DOI : 10.1038 / ng.2007.21 . - PMID 17994021 .
- ↑ Zeitlinger, J. , Stark, A. , Kellis, M. , Hong, JW , Nechaev, S. , Adelman, K. , Levine, M. , Young, RA . (English) // Nature genetics. - 2007. - Vol. 39, no. 12 - P. 1512-1516. - DOI : 10.1038 / ng.2007.26 . - PMID 17994019 .