IDENTIFICATION AND CHARACTERIZATION OF GENES THAT ARE REQUIRED FOR THE ACCELERATED DEGRADATION OF MESSENGER-RNAS CONTAINING A PREMATURE TRANSLATIONAL TERMINATION CODON
IDENTIFICATION AND CHARACTERIZATION OF GENES THAT ARE REQUIRED FOR THE ACCELERATED DEGRADATION OF MESSENGER-RNAS CONTAINING A PREMATURE TRANSLATIONAL TERMINATION CODON
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DOI：
10.1101/gad.9.4.423
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发表时间：
1995-02-15
影响因子：
10.5
通讯作者：
PELTZ, SW
中科院分区：
文献类型：
--
作者：
CUI, Y;HAGAN, KW;PELTZ, SW
在原核生物和真核生物中，基因中的无义突变可以提高从该基因转录的mRNA的衰变率，这种现象被描述为无义介导的mRNA衰变。在酵母中，UPF 1和UPF 3基因的产物是这种衰变途径所必需的，在这份报告中，我们专注于鉴定和表征无义mRNA快速衰变所需的其他因素。我们目前的证据表明，UPF 2基因的产品是一个新的因素参与这一衰变途径。UPF 2基因的突变或其从染色体上的缺失导致含无义mRNA的稳定化，而野生型转录物的衰减不受影响。分离UPF 2基因，并表征其转录物，我们的研究结果表明，UPF 2基因编码一个推定的126.7 kD蛋白质，其羧基端（-D-E）（n）具有酸性区域。在许多核仁和转录激活蛋白中发现。UPF 2转录物的长度为3600个核苷酸，并且在其5'端附近含有内含子。UPF 2基因不适合营养生长，但发现upf 2 Delta菌株对翻译延伸抑制剂放线菌酮比UPF 2（+）更敏感。对其他参与无义介导的mRNA衰变的等位基因的遗传分析显示，UPF 2基因与先前鉴定的sua 1等位基因是等位的，sua 1等位基因是先前显示的框外ATG插入的抑制因子，其减少了CYC 1基因的正常ATG的翻译起始。此外，我们证明了另一个抑制这种cyc 1突变，sua 6，是等位基因upf 3，以前确定的病变参与无义介导的mRNA衰变。
In both prokaryotes and eukaryotes nonsense mutations in a gene can enhance the decay rate of the mRNA transcribed from that gene, a phenomenon described as nonsense-mediated mRNA decay. In yeast, the products of the UPF1 and UPF3 genes are required for this decay pathway, and in this report we focus on the identification and characterization of additional factors required for rapid decay of nonsense-containing mRNAs. We present evidence that the product of the UPF2 gene is a new factor involved in this decay pathway. Mutation of the UPF2 gene or deletion of it from the chromosome resulted in stabilization of nonsense-containing mRNAs, whereas the decay of wild-type transcripts was not affected, The UPF2 gene was isolated, and its transcript was characterized, Our results demonstrate that the UPF2 gene encodes a putative 126.7-kD protein with an acidic region at its carboxyl terminus (-D-E)(n) found in many nucleolar and transcriptional activator proteins. The UPF2 transcript is 3600 nucleotides in length and contains an intron near its 5' end. The UPF2 gene is dispensable for vegetative growth, but upf2 Delta strains were found to be more sensitive to the translational elongation inhibitor cycloheximide than UPF2(+). A genetic analysis of other alleles proposed to be involved in nonsense-mediated mRNA decay revealed that the UPF2 gene is allelic to the previously identified sua1 allele, a suppressor of an out-of-frame ATG insertion shown previously to reduce translational initiation from the normal ATG of the CYC1 gene. In addition, we demonstrate that another suppressor of this cyc1 mutation, sua6, is allelic to upf3, a previously identified lesion involved in nonsense-mediated mRNA decay.