Alternative splicing of DSP1 enhances snRNA accumulation by promoting transcription termination and recycle of the processing complex.
Alternative splicing of DSP1 enhances snRNA accumulation by promoting transcription termination and recycle of the processing complex.
复制标题
DSP1 的选择性剪接通过促进转录终止和加工复合物的循环来增强 snRNA 的积累。
DOI：
10.1073/pnas.2002115117
复制
发表时间：
2020
影响因子：
11.1
通讯作者：
Liu Yunfeng
中科院分区：
文献类型：
--
作者：
Wang Weili;Pu Xuepiao;Yang Siyu;Feng Yujie;Lin Chan;Li Mu;Li Xi;Li Huali;Meng Chunmei;Xie Qingjun;Yu Bin;Liu Yunfeng
核小RNA（Small nuclear RNA，snRNA）是剪接体的基本组成部分，在剪接过程中起着重要作用。它们的生物发生是受时空调控的。然而，相关机制仍然知之甚少。缺陷型snRNA加工蛋白（Defective in snRNA processing，DSP 1）是DSP 1复合体的重要组成部分，它通过对一级snRNA转录本（presnRNA）的共转录内切酶切割，催化植物snRNA 3′端成熟。在这里，我们发现DSP 1在花粉和胚胎中进行选择性剪接，产生两种剪接变体，DSP 1 α和DSP 1 β。与DSP 1 α不同，DSP 1 β不需要presnRNA 3′-末端切割。相反，它与DSP 1 α竞争与DSP 1复合物的催化亚基CPSF 73-I的相互作用，CPSF 73-I促进从snRNA位点的3′端有效释放CPSF 73-I和DNA依赖性RNA聚合酶II（Pol II），从而促进snRNA转录终止，导致花粉中snRNA水平增加。总之，这项研究揭示了空间调节snRNA积累的机制。
Small nuclear RNAs (snRNAs) are the basal components of the spliceosome and play crucial roles in splicing. Their biogenesis is spatiotemporally regulated. However, related mechanisms are still poorly understood. Defective in snRNA processing (DSP1) is an essential component of the DSP1 complex that catalyzes plant snRNA 3′-end maturation by cotranscriptional endonucleolytic cleavage of the primary snRNA transcripts (presnRNAs). Here, we show thatDSP1is subjected to alternative splicing in pollens and embryos, resulting in two splicing variants,DSP1α andDSP1β. Unlike DSP1α, DSP1β is not required for presnRNA 3′-end cleavage. Rather, it competes with DSP1α for the interaction with CPSF73-I, the catalytic subunit of the DSP1 complex, which promotes efficient release of CPSF73-I and the DNA-dependent RNA polymerease II (Pol II) from the 3′ end of snRNA loci thereby facilitates snRNA transcription termination, resulting in increased snRNA levels in pollens. Taken together, this study uncovers a mechanism that spatially regulates snRNA accumulation.