Nuclear export as a key arbiter of 鈥渕RNA identity鈥?in eukaryotes
- 作者：Alexander F. Palazzo ; alex.palazzo@utoronto.ca ; Abdalla Akef
- 关键词：ALREX ; (Alternative mRNA Export) ; CBC ; (Cap Binding Complex) ; CTD ; (Carboxy-Terminal Domain) ; EJC ; (Exon Junction Complex) ; mRNP ; (Messenger Ribonucleoprotein) ; MSCR ; (Mitochondrial Targeting Sequence Coding Region) ; NPC ; (Nuclear Pore Complex) ; Pol II ; (
- 刊名：Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms
- 出版年：2012
- 期刊代码：P11_18749399
- 类别：bio
- 出版时间：June, 2012
- 卷：1819
- 期：6
- 页码：566-577
- 文件大小：771 K
摘要
Over the past decade, various studies have indicated that most of the eukaryotic genome is transcribed at some level. The pervasiveness of transcription might seem surprising when one considers that only a quarter of the human genome comprises genes (including exons and introns) and less than 2%codes for protein. This conundrum is partially explained by the unique evolutionary pressures that are imposed on species with small population sizes, such as eukaryotes. These conditions promote the expansion of introns and non-functional intergenic DNA, and the accumulation of cryptic transcriptional start sites. As a result, the eukaryotic gene expression machinery must effectively evaluate whether or not a transcript has all the hallmarks of a protein-coding mRNA. If a transcript contains these features, then positive feedback loops are activated to further stimulate its transcription, processing, nuclear export and ultimately, translation. However if a transcript lacks features associated with 鈥渕RNA identity鈥? then the RNA is degraded and/or used to inhibit further transcription and translation of the gene. Here we discuss how mRNA identity is assessed by the nuclear export machinery in order to extract meaningful information from the eukaryotic genome. In the process, we provide an explanation of why certain sequences that are enriched in protein-coding genes, such as the signal sequence coding region, promote mRNA nuclear export in vertebrates. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.