The DECD box putative ATPase Sub2p is an early mRNA export factor
The DECD box putative ATPase Sub2p is an early mRNA export factor
复制标题
DOI：
10.1016/s0960-9822(01)00529-2
复制
发表时间：
2001-10-30
期刊：
影响因子：
9.2
通讯作者：
Libri, D
中科院分区：
文献类型：
--
作者：
Jensen, TH;Boulay, J;Libri, D
核mRNA代谢依赖于转录、加工和核输出之间的相互作用。RNA聚合酶II转录物在核内经历主要重排，其包括mRNA前体结构的改变以及在跨核膜运输之前添加甚至去除蛋白质。这种mRNP重塑步骤被认为需要RNA解旋酶/ATP酶的活性。一种这样的蛋白质，DECD盒RNA依赖性ATP酶Sub 2 p/UAP 56，参与剪接体组装的早期和晚期步骤[1-4]。在这里，我们报告了一个更一般的功能酿酒酵母Sub 2 p的mRNA核输出。我们观察到一个快速和戏剧性的核积累的聚（A）（+）RNA的菌株携带突变等位基因sub 2。引人注目的是，一个无内含子的转录本，HSP 104，也积累在细胞核中，这表明Sub 2 p的功能不限于剪接事件。HSP 104转录本定位于单个核焦点中，这被认为是在其转录位点处或附近。有趣的是，Sub 2 p显示出与RNA聚合酶II相关的DNA/DNA：RNA解旋酶Rad 3 p以及核RNA外泌体组分Rrp 6p的强遗传和功能相互作用，其独立地涉及mRNA在转录位点的保留[5]。综上所述，我们的数据表明，Sub 2 p功能在mRNA输出过程的早期步骤。
Nuclear mRNA metabolism relies on the interplay between transcription, processing, and nuclear export. RNA polymerase II transcripts experience major rearrangements within the nucleus, which include alterations in the structure of the mRNA precursors as well as the addition and perhaps even removal of proteins prior to transport across the nuclear membrane. Such mRNP-remodeling steps are thought to require the activity of RNA helicases/ATPases. One such protein, the DECD box RNA-dependent ATPase Sub2p/UAP56, is involved in both early and late steps of spliceosome assembly [1-4]. Here, we report a more general function of Saccharomyces cerevisiae Sub2p in mRNA nuclear export. We observe a rapid and dramatic nuclear accumulation of poly(A)(+) RNA in strains carrying mutant alleles of sub2. Strikingly, an intronless transcript, HSP104, also accumulates in nuclei, suggesting that Sub2p function is not restricted to splicing events. The HSP104 transcripts are localized in a single nuclear focus that is suggested to be at or near their site of transcription. Intriguingly, Sub2p shows strong genetic and functional interactions with the RNA polymerase II-associated DNA/DNA:RNA helicase Rad3p as well as the nuclear RNA exosome component Rrp6p, which was independently implicated in the retention of mRNAs at transcription sites [5]. Taken together, our data suggest that Sub2p functions at an early step in the mRNA export process.