可变剪切整合子DSP1AS调控snRNA含量机制的研究

snRNA是真核生物必需的一类非编码RNA。snRNA含量随组织发育时期或部位的不同而呈现差异化，而且snRNA含量的差异化调控对组织发育十分重要。snRNA的转录及成熟过程已比较清楚，但snRNA组织差异化的调控机制则知之甚少。.我们之前发现DSP1与CPSF73-I结合并参与snRNA的转录及成熟。近期发现DSP1基因的可变剪切模式DSP1AS，其在花粉和胚胎中特异表达，同时在花粉和胚胎发育中有重要作用。DSP1AS不参与snRNA的转录及成熟，但调控相应组织snRNA含量的差异化。我们的数据显示DSP1AS在snRNA转录后期与DSP1竞争性结合CPSF73-I，使CPSF73-I从转录复合物中解离，进而促进转录复合物的解聚和后转录过程的终止，最终提高snRNA转录效率和含量。.本研究将拓展对snRNA合成及含量调控的认识，有助于揭示snRNA组织差异化的机制。

The contents level of snRNA known as critical non-coding RNA of eukaryotic cells had been found changed in associated with specific tissue or developmental events, and relatively higher in reproductive tissues of plant. Despite the detail about snRNAs biosynthesis including transcription and procession has been well characterized, the molecular mechanisms underlying regulation of snRNA contents level in specific tissue or developmental events is not currently well understood. .The Defective in snRNA Processing 1 (DSP1) component complex is responsible for snRNA transcription and maturation in plant, also is essential for pollen and embryo development. Here, we found a novel alternative splicing variant of DSP1 (DSP1AS) was indispensable for the development of pollen and embryo. Moreover, DSP1AS contributes to the higher snRNAs content in pollen by enhancing snRNA transcription. We reveal DSP1AS competes with DSP1 to bind CPSF73-I and releases CPSF73-I contained snRNA transcription complex from downstream of snRNA loci, thus promotes transcript termination. .Our research present a new alternative spliced integrator involves in elevating snRNA in pollen of Arabidopsis, provide a novel insight into the snRNAs content regulation.