Identification of Edc3p as an enhancer of mRNA decapping in Saccharomyces cerevisiae
Identification of Edc3p as an enhancer of mRNA decapping in Saccharomyces cerevisiae
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DOI：
10.1534/genetics.166.2.729
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发表时间：
2004-02-01
期刊：
影响因子：
3.3
通讯作者：
Parker, R
中科院分区：
文献类型：
--
作者：
Kshirsagar, M;Parker, R
酵母中的mRNA衰变的主要途径是去烯基化，其次是去核糖核酸酶和5‘-3’核酸外切酶。使用电子计算机方法来鉴定参与mRNA衰变途径的新蛋白质。其中一个蛋白质Edc3p被鉴定为一种功能未知的保守蛋白质，它与几种参与mRNA解离和5‘-3’降解的蛋白质具有广泛的双杂交相互作用，这些蛋白质包括Dcp1p、Dcp2p、Dh1p、Lsm1p和5‘-3’外切酶Xrn1p。我们发现，当脱帽酶被DCP1或DCP2基因的温度敏感等位基因破坏时，Edc3p可以刺激酵母中不稳定和稳定的mRNAs的mRNA解离。在这些情况下，在允许的温度下，EDC3的缺失导致了协同的mRNA解离缺陷。当edc3Delta与lsm1Delta、dhh1Delta或pat1Delta突变结合时没有任何影响，这些突变似乎会影响解帽途径的早期步骤。这表明Edc3p本身特异性地影响解离酶本身的功能。GFP标记的Edc3p与解离的功能一致，定位于参与mRNA解离的细胞质焦点，称为P-小体。这些结果表明Edc3p是参与解壳反应的一种新蛋白。
The major pathway of mRNA decay in yeast initiates with deadenylation, followed by mRNA decapping and 5'-3' exonuclease digestion. An in silico approach was used to identify new proteins involved in the mRNA decay pathway. One such protein, Edc3p, was identified as a conserved protein of unknown function having extensive two-hybrid interactions with several proteins involved in mRNA decapping and 5'-3' degradation including Dcp1p, Dcp2p, Dhh1p, Lsm1p, and the 5'-3' exonuclease, Xrn1p. We show that Edc3p can stimulate mRNA decapping of both unstable and stable mRNAs in yeast when the decapping enzyme is compromised by temperature-sensitive alleles of either the DCP1 or the DCP2 genes. In these cases, deletion of EDC3 caused a synergistic mRNA-decapping defect at the permissive temperatures. The edc3Delta had no effect when combined with the lsm1Delta, dhh1Delta, or pat1Delta mutations, which appear to affect an early step in the decapping pathway. This suggests that Edc3p specifically affects the function of the decapping enzyme per se. Consistent with a functional role in decapping, GFP-tagged Edc3p localizes to cytoplasmic foci involved in mRNA decapping referred to as P-bodies. These results identify Edc3p as a new protein involved in the decapping reaction.