A SMALL SEGMENT OF THE MAT-ALPHA-1 TRANSCRIPT PROMOTES MESSENGER-RNA DECAY IN SACCHAROMYCES-CEREVISIAE - A STIMULATORY ROLE FOR RARE CODONS
A SMALL SEGMENT OF THE MAT-ALPHA-1 TRANSCRIPT PROMOTES MESSENGER-RNA DECAY IN SACCHAROMYCES-CEREVISIAE - A STIMULATORY ROLE FOR RARE CODONS
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DOI：
10.1128/mcb.13.9.5141
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发表时间：
1993-09-01
影响因子：
5.3
通讯作者：
PARKER, R
中科院分区：
文献类型：
--
作者：
CAPONIGRO, G;MUHLRAD, D;PARKER, R
真核转录物衰减率的差异可以由mRNAs中的离散序列元件决定。通过对嵌合转录本和内部缺失的分析，我们已经确定了MATalpha1mRNA编码区的一个65个核苷酸的片段，称为MATalpha1不稳定元件，它足以使稳定的PGK1报告转录本变得不稳定，并加速不稳定的MATalpha1mRNA的周转。该65个核苷酸元件由两部分组成，一部分位于5‘33个核苷酸内，另一个位于3’32个核苷酸内。第一部分在功能上可以被含有稀有密码子的序列取代，它本身不能促进快速衰变，但可以增强3‘32核苷酸(MATalpha1mRNA中第234到266位)在加速周转方面的作用。MATalpha1mRNA的第二部分(第265至290号核苷酸)也足以在罕见密码子的3‘端定位时破坏PGK1报告转录本的稳定性，这表明MATalpha1不稳定元件的3’一半在MATalpha1mRNA中有功能重复。观察到稀有密码子是由65个核苷酸组成的MATalpha1不稳定元件的一部分，这表明翻译和mRNA衰变之间可能存在联系。
Differences in decay rates of eukaryotic transcripts can be determined by discrete sequence elements within mRNAs. Through the analysis of chimeric transcripts and internal deletions, we have identified a 65-nucleotide segment of the MATalpha1 mRNA coding region, termed the MATalpha1 instability element, that is sufficient to confer instability to a stable PGK1 reporter transcript and that accelerates turnover of the unstable MATalpha1 mRNA. This 65-nucleotide element is composed of two parts, one located within the 5' 33 nucleotides and the second located in the 3' 32 nucleotides. The first part, which can be functionally replaced by sequences containing rare codons, is unable to promote rapid decay by itself but can enhance the action of the 3' 32 nucleotides (positions 234 to 266 in the MATalpha1 mRNA) in accelerating turnover. A second portion of the MATalpha1 mRNA (nucleotides 265 to 290) is also sufficient to destabilize the PGK1 reporter transcript when positioned 3' of rare codons, suggesting that the 3' half of the MATalpha1 instability element is functionally reiterated within the MATalpha1 mRNA. The observation that rare codons are part of the 65-nucleotide MATalpha1 instability element suggests possible mechanisms through which translation and mRNA decay may be linked.