Nascent-seq 表明果蝇中转录过程中广泛存在的前体 mRNA 剪接。
Nascent-seq indicates widespread cotranscriptional pre-mRNA splicing in Drosophila.
机构信息
Howard Hughes Medical Institute, National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts 02454, USA.
出版信息
Genes Dev. 2011 Dec 1;25(23):2502-12. doi: 10.1101/gad.178962.111.
To determine the prevalence of cotranscriptional splicing in Drosophila, we sequenced nascent RNA transcripts from Drosophila S2 cells as well as from Drosophila heads. Eighty-seven percent of the introns assayed manifest >50% cotranscriptional splicing. The remaining 13% are cotranscriptionally spliced poorly or slowly, with ∼3% being almost completely retained in nascent pre-mRNA. Although individual introns showed slight but statistically significant differences in splicing efficiency, similar global levels of splicing were seen from both sources. Importantly, introns with low cotranscriptional splicing efficiencies are present in the same primary transcript with efficiently spliced introns, indicating that splicing is intron-specific. The analysis also indicates that cotranscriptional splicing is less efficient for first introns, longer introns, and introns annotated as alternative. Finally, S2 cells expressing the slow RpII215(C4) mutant show substantially less intron retention than wild-type S2 cells.
为了确定果蝇中转录共剪接的普遍性，我们对果蝇 S2 细胞和果蝇头部的新生 RNA 转录本进行了测序。检测到的 87%的内含子表现出>50%的转录共剪接。其余 13%的内含子剪接不良或缓慢，其中约 3%的内含子在新生前体 mRNA 中几乎完全被保留。虽然单个内含子的剪接效率略有但具有统计学意义的差异，但来自两种来源的剪接效率都相似。重要的是，具有低转录共剪接效率的内含子与有效剪接的内含子存在于同一初级转录本中，表明剪接是内含子特异性的。该分析还表明，第一内含子、较长的内含子和被注释为替代的内含子的转录共剪接效率较低。最后，表达慢剪接 RpII215(C4)突变体的 S2 细胞显示出的内含子保留明显少于野生型 S2 细胞。
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