劈理(地质)
构象变化
生物
聚腺苷酸
抄写(语言学)
细胞生物学
生物物理学
分子生物学
核糖核酸
生物化学
基因
语言学
断裂(地质)
哲学
古生物学
作者
Huimin Zhang,Frank Rigo,Harold G. Martinson
出处
期刊:Molecular Cell
[Elsevier]
日期:2015-08-06
卷期号:59 (3): 437-448
被引量:43
标识
DOI:10.1016/j.molcel.2015.06.008
摘要
Transcription termination for genes encoding polyadenylated mRNAs requires a functional poly(A) signal (PAS) in the nascent pre-mRNA. Often called PAS-dependent termination, or PADT, it is widely assumed that the PAS requirement reflects an obligatory poly(A) site cleavage requirement for termination. Cleavage is thought to provide entry for a 5'-to-3' exonuclease that targets RNA polymerase II via the nascent transcript-i.e., the torpedo model. To assess the role of cleavage in PADT, we developed a PADT assay using HeLa nuclear extract. Here we examine the basal mechanism of PADT and show that cleavage at the poly(A) site is not required for PADT. Isolated elongation complexes undergo termination in a PAS-dependent manner when incubated in buffer, in the absence of extract, nucleotides, or cleavage at the poly(A) site. Thus, PADT-proficient complexes undergo a conformational change that triggers termination. PADT is inhibited by α-amanitin, which presumably blocks the required conformational change.
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