Back تذييل بعديد الأدينيلات Arabic Poliadenilacija BS Poly(A) konec Czech Polyadenylierung German Poliadenilación Spanish پلیآدنیله شدن Persian Polyadénylation French Poliadenilación Galician פוליאדנילציה HE Poliadenilasi ID
Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In eukaryotes, polyadenylation is part of the process that produces mature mRNA for translation. In many bacteria, the poly(A) tail promotes degradation of the mRNA. It, therefore, forms part of the larger process of gene expression.
The process of polyadenylation begins as the transcription of a gene terminates. The 3′-most segment of the newly made pre-mRNA is first cleaved off by a set of proteins; these proteins then synthesize the poly(A) tail at the RNA's 3′ end. In some genes these proteins add a poly(A) tail at one of several possible sites. Therefore, polyadenylation can produce more than one transcript from a single gene (alternative polyadenylation), similar to alternative splicing.[1]
The poly(A) tail is important for the nuclear export, translation and stability of mRNA. The tail is shortened over time, and, when it is short enough, the mRNA is enzymatically degraded.[2] However, in a few cell types, mRNAs with short poly(A) tails are stored for later activation by re-polyadenylation in the cytosol.[3] In contrast, when polyadenylation occurs in bacteria, it promotes RNA degradation.[4] This is also sometimes the case for eukaryotic non-coding RNAs.[5][6]
mRNA molecules in both prokaryotes and eukaryotes have polyadenylated 3′-ends, with the prokaryotic poly(A) tails generally shorter and fewer mRNA molecules polyadenylated.[7]
- ^ Cite error: The named reference
Proudfootwas invoked but never defined (see the help page). - ^ Guhaniyogi J, Brewer G (March 2001). "Regulation of mRNA stability in mammalian cells". Gene. 265 (1–2): 11–23. doi:10.1016/S0378-1119(01)00350-X. PMC 3340483. PMID 11255003.
- ^ Cite error: The named reference
Richterwas invoked but never defined (see the help page). - ^ Steege DA (August 2000). "Emerging features of mRNA decay in bacteria". RNA. 6 (8): 1079–90. doi:10.1017/S1355838200001023. PMC 1369983. PMID 10943888.
- ^ Zhuang Y, Zhang H, Lin S (June 2013). "Polyadenylation of 18S rRNA in algae(1)". Journal of Phycology. 49 (3): 570–9. Bibcode:2013JPcgy..49..570Z. doi:10.1111/jpy.12068. PMID 27007045. S2CID 19863143.
- ^ Anderson JT (August 2005). "RNA turnover: unexpected consequences of being tailed". Current Biology. 15 (16): R635-8. Bibcode:2005CBio...15.R635A. doi:10.1016/j.cub.2005.08.002. PMID 16111937. S2CID 19003617.
- ^ Sarkar N (June 1997). "Polyadenylation of mRNA in prokaryotes". Annual Review of Biochemistry. 66 (1): 173–97. doi:10.1146/annurev.biochem.66.1.173. PMID 9242905.