In vivo evidence that defects in the transcriptional elongation factors RPB2, TFIIS, and SPT5 enhance upstream poly(A) site utilization
In vivo evidence that defects in the transcriptional elongation factors RPB2, TFIIS, and SPT5 enhance upstream poly(A) site utilization
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DOI：
10.1128/mcb.23.21.7887-7901.2003
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发表时间：
2003-11-01
影响因子：
5.3
通讯作者：
Denis, CL
中科院分区：
文献类型：
--
作者：
Cui, YJ;Denis, CL
虽然许多蛋白质参与延伸过程，但这些因素中的大多数的作用机制仍然不清楚，主要是因为缺乏合适的体内模型系统。我们在酵母中发现了几个含有内部poly（A）位点的基因，其全长mRNA的形成因RNA聚合酶11亚基RPB 2、延伸因子SPT 5或TFIIS的突变而减少。RPB 2和SPT 5缺陷也促进了含有多个3' poly（A）信号序列的基因上游poly（A）位点的利用，支持了延伸在差异poly（A）位点选择中的作用。我们的数据表明，延伸缺陷会导致转录暂停或停滞增加，从而导致内部或上游poly（A）位点的利用增加。因此，如果基因含有内部poly（A）位点，则可以在体内观察到转录暂停或停滞，从而允许对延伸过程进行生物化学和遗传学研究。
While a number of proteins are involved in elongation processes, the mechanism for action of most of these factors remains unclear primarily because of the lack of suitable in vivo model systems. We identified in yeast several genes that contain internal poly(A) sites whose full-length mRNA formation is reduced by mutations in RNA polymerase 11 subunit RPB2, elongation factor SPT5, or TFIIS. RPB2 and SPT5 defects also promoted the utilization of upstream poly(A) sites for genes that contain multiple 3' poly(A) signaling sequences, supporting a role for elongation in differential poly(A) site choice. Our data suggest that elongation defects cause increased transcriptional pausing or arrest that results in increased utilization of internal or upstream poly(A) sites. Transcriptional pausing or arrest can therefore be visualized in vivo if a gene contains internal poly(A) sites, allowing biochemical and genetic study of the elongation process.