Differential 3' Processing of Specific Transcripts Expands Regulatory and Protein Diversity Across Neuronal Cell Types

Alternative polyadenylation (APA) regulates mRNA translation, stability, and protein localization. However, it is unclear to what extent APA regulates these processes uniquely in specific cell types. Using a new technique, cTag-PAPERCLIP, we discovered significant differences in APA between the principal types of mouse cerebellar neurons, the Purkinje and granule cells, as well as between proliferating and differentiated granule cells. Transcripts that differed in APA in these comparisons were enriched in key neuronal functions and many differed in coding sequence in addition to 3'UTR length. Overall design: Examination of Pabpc1-GFP bound RNA in cerebellar granule in Purkinje cells and cerebellar granule cells during development using a cTag-PAPERCLIP. RNA-seq of RNA from cerebellar granule cells at two developmental timepoints to compare with cTag-PAPERCLIP data.可变聚腺苷酸化（Alternative polyadenylation, APA）可调控mRNA的翻译、稳定性与蛋白质定位。然而目前尚不明确，APA在多大程度上仅在特定细胞类型中特异性调控上述过程。本研究借助新型技术cTag-PAPERCLIP，发现小鼠小脑神经元的两类主要类型——浦肯野细胞与颗粒细胞之间，以及增殖态与分化态颗粒细胞之间，APA存在显著差异。在上述比较中APA模式存在差异的转录本，显著富集于关键神经元功能相关通路中，且其中多数除3'非翻译区（3'UTR）长度发生改变外，其编码序列亦存在差异。实验整体设计：借助cTag-PAPERCLIP技术，检测发育过程中小脑浦肯野细胞及颗粒细胞内与Pabpc1-GFP结合的RNA；对两个发育时间点的小脑颗粒细胞总RNA进行RNA测序，以与cTag-PAPERCLIP实验数据开展对比分析。