Fritz David T, Bergman Naomi, Kilpatrick Walter J, Wilusz Carol J, Wilusz Jeffrey
Department of Biochemistry and Molecular Biology, UMDNJ-New Jersey Medical School, Newark, NJ 07101, USA.
Cell Biochem Biophys. 2004;41(2):265-78. doi: 10.1385/CBB:41:2:265.
The majority of messenger RNA (mRNA) decay in mammalian cells appears to be the work of a series of RNA exoribonucleases. A set of multiple poly(A)-specific deadenylases has been identified, some, if not most, of which are likely to play a role in the key first step of mRNA turnover--the regulated shortening of the poly(A) tail. After deadenylation, the transcript likely gets degraded by either a 5'-to-3' or a 3'-to-5' exonucleolytic pathway. Interestingly, multiple exonucleases have been identified for both of these pathways that appear to form multicomponent complexes with diverse roles in cellular biology. Therefore these enzymes appear not only to be important components of the mRNA turnover machinery, but also may function in a networked fashion in the post-transcriptional control of gene expression.
哺乳动物细胞中大多数信使核糖核酸（mRNA）的降解似乎是一系列核糖核酸外切酶的作用。已经鉴定出一组多种聚腺苷酸特异性去腺苷酸酶，其中一些（即便不是大多数）可能在mRNA周转的关键第一步——聚腺苷酸尾巴的调控性缩短中发挥作用。去腺苷酸化后，转录本可能通过5'至3'或3'至5'的核酸外切酶途径被降解。有趣的是，已经为这两种途径鉴定出多种核酸外切酶，它们似乎形成了在细胞生物学中具有不同作用的多组分复合物。因此，这些酶不仅似乎是mRNA周转机制的重要组成部分，而且可能在基因表达的转录后控制中以网络方式发挥作用。
