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Abstract：
Alternative polyadenylation (APA) is a widespread post-transcriptional modification method that changes the 3\' ends of transcripts by altering poly(A) site usage. However, the longitudinal transcriptomic 3\' end profile and its mechanism of action are poorly understood. We applied diurnal time-course poly(A) tag sequencing (PAT-seq) for Arabidopsis and identified 3284 genes that generated both rhythmic and arrhythmic transcripts. These two classes of transcripts appear to exhibit dramatic differences in expression and translation activisty. The asynchronized transcripts derived by APA are embedded with different poly(A) signals, especially for rhythmic transcripts, which contain higher AAUAAA and UGUA signal proportions. The Pol II occupancy maximum is reached upstream of rhythmic poly(A) sites, while it is present directly at arrhythmic poly(A) sites. Integrating H3K9ac and H3K4me3 time-course data analyses revealed that transcriptional activation of histone markers may be involved in the differentiation of rhythmic and arrhythmic APA transcripts. These results implicate an interplay between histone modification and RNA 3\'-end processing, shedding light on the mechanism of transcription rhythm and alternative polyadenylation.
摘要：
选择性聚腺苷酸化（APA）是一种广泛的转录后修饰方法，通过改变poly（A）位点的使用来改变转录本的3'末端。然而,纵向转录组3'端谱及其作用机制知之甚少。我们对拟南芥应用了昼夜时程poly（A）标签测序（PAT-seq），并鉴定了产生节律和心律失常转录本的3284个基因。这两类转录本似乎在表达和翻译活动方面表现出巨大的差异。由APA衍生的异步转录本嵌入不同的poly（A）信号，尤其是有节奏的成绩单，其中包含较高的AAUAAA和UGUA信号比例。在有节奏的聚（A）站点的上游达到了PolII的最大占有率，而它直接存在于心律失常聚（A）位点。整合H3K9ac和H3K4me3时程数据分析显示，组蛋白标志物的转录激活可能参与节律性和心律失常性APA转录本的分化。这些结果暗示了组蛋白修饰和RNA3'端加工之间的相互作用，阐明转录节律和选择性聚腺苷酸化的机制。
