smg-7 is required for mRNA surveillance in Caenorhabditis elegans.
smg-7 is required for mRNA surveillance in Caenorhabditis elegans.
复制标题
秀丽隐杆线虫 mRNA 监测需要 smg-7。
DOI：
10.1093/genetics/151.2.605
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发表时间：
1999
期刊：
影响因子：
3.3
通讯作者：
Anderson,P
中科院分区：
文献类型：
--
作者：
Cali,BM;Kuchma,SL;Latham,J;Anderson,P
含有提前终止密码子的真核mRNA比它们的野生型对应物降解得更快，这种现象称为“无义介导的mRNA衰变”（NMD）或“mRNA监视”。六个先前描述的秀丽隐杆线虫基因，smg-1至smg-6的功能是NMD所必需的。尽管无义突变体mRNA在smg（+）遗传背景中不稳定，但此类mRNA在smg（-）背景中具有正常稳定性。以前的smg突变筛选可能没有确定所有参与NMD的基因，但鉴定其他smg基因的努力受到以下事实的限制，即在全基因组筛选中鉴定的几乎90%的smg突变是smg-1，smg-2或smg-5的等位基因。我们描述了一种改良的筛选smg突变的方法，排除了smg-1，smg-2和smg-5的等位基因。使用这个屏幕，我们已经确定并克隆了smg-7，一个以前未知的基因，我们显示是NMD所需的。据预测，SMG-7编码一种新的蛋白质，该蛋白质含有酸性羧基末端和两个可能的三肽重复序列。我们提供的证据表明，smg-7与先前表征的基因lin-45共转录，并表明smg-7的无效等位基因赋予NMD的温度敏感性缺陷。
Eukaryotic mRNAs that contain premature stop codons are degraded more rapidly than their wild-type counterparts, a phenomenon termed “nonsense-mediated mRNA decay” (NMD) or “mRNA surveillance.” Functions of six previously described Caenorhabditis elegans genes, smg-1 through smg-6, are required for NMD. Whereas nonsense mutant mRNAs are unstable in smg(+) genetic backgrounds, such mRNAs have normal stability in smg(–) backgrounds. Previous screens for smg mutations have likely not identified all genes involved in NMD, but efforts to identify additional smg genes are limited by the fact that almost 90% of smg mutations identified in genome-wide screens are alleles of smg-1, smg-2, or smg-5. We describe a modified screen for smg mutations that precludes isolating alleles of smg-1, smg-2, and smg-5. Using this screen, we have identified and cloned smg-7, a previously uncharacterized gene that we show is required for NMD. smg-7 is predicted to encode a novel protein that contains an acidic carboxyl terminus and two probable tetratricopeptide repeats. We provide evidence that smg-7 is cotranscribed with the previously characterized gene lin-45 and show that null alleles of smg-7 confer a temperature-sensitive defect in NMD.