The RNA processing exosome is linked to elongating RNA polymerase II in Drosophila
The RNA processing exosome is linked to elongating RNA polymerase II in Drosophila
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DOI：
10.1038/nature01181
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发表时间：
2002-12-26
期刊：
影响因子：
64.8
通讯作者：
Lis, JT
中科院分区：
文献类型：
--
作者：
Andrulis, ED;Werner, J;Lis, JT
RNA聚合酶II延伸复合物含有几种促进转录延伸并催化前体信使RNA（pre-mRNAs）加工的因子（1-3）。保守的延伸因子Spt 6被快速和稳健地募集到活性转录位点（4，5）。在这里，我们表明果蝇Spt 6（dSpt 6）与外泌体共纯化，外泌体是一种3'至5'外切核糖核酸酶的复合物，其涉及结构RNA的加工和不适当加工的前mRNA的降解（6-10）。果蝇核提取物的免疫沉淀分析表明，外泌体也与延伸因子dSpt 5和RNA聚合酶II。在体内，外泌体亚基与dSpt 6在正常发育过程中在多线染色体上的转录活性位点共定位，并且在基因诱导时被强烈招募到热休克位点。在更高的分辨率下，染色质免疫沉淀分析表明外泌体被招募到热休克基因的转录活性单位。这些数据为外泌体介导的前mRNA监视伴随转录延伸的假设提供了物理基础。
The RNA polymerase II elongation complex contains several factors that facilitate transcription elongation and catalyse the processing of precursor messenger RNAs (pre-mRNAs)(1-3). The conserved elongation factor Spt6 is recruited rapidly and robustly to sites of active transcription(4,5). Here we show that Drosophila Spt6 (dSpt6) co-purifies with the exosome, a complex of 3' to 5' exoribonucleases that is implicated in the processing of structural RNA and in the degradation of improperly processed pre-mRNA(6-10). Immunoprecipitation assays of Drosophila nuclear extracts show that the exosome also associates with the elongation factor dSpt5 and RNA polymerase II. In vivo, exosome subunits colocalize with dSpt6 at transcriptionally active loci on polytene chromosomes during normal development and are strongly recruited to heat-shock loci on gene induction. At higher resolution, chromatin immunoprecipitation analysis shows that the exosome is recruited to transcriptionally active units of heat-shock genes. These data provide a physical basis for the hypothesis that exosome-mediated pre-mRNA surveillance accompanies transcription elongation.