摘要
Natural antisense transcripts （NAT） and alternative polyadenylation （APA） of messenger RNA （mRNA） are important contributors of transcriptome complexity, each playing a critical role in multiple biological processes. However, whether they have crosstalk and function collaboratively is unclear. We discovered that APA enriched in human sense-antisense （S-AS） gene pairs, and finally focused on RNASEH2C-KAT5 S-AS pair for further study. In cis but not in trans over-expression of the antisense KAT5 gene promoted the usage of distal polyA （pA） site in sense gene RNASEH2C, which generated longer 3＇ untranslated region （3＇UTR） and produced less protein, accompanying with slowed cell growth. Mechanistically, elevated Pol II occupancy coupled with SRSF3 could explain the higher usage of distal pA site. Finally, NAT-mediated downregulation of sense gene＇s protein level in RNASEH2C.KAT5 pair was specific for human rather than mouse, which lacks the distal pA site of RNASEH2C. We provided the first evidence to support that certain gene affected phenotype may not by the protein of its own, but by affecting the expression of its overlapped gene through APA, implying an unexpected view for understanding the link between genotype and phenotype.
Natural antisense transcripts （NAT） and alternative polyadenylation （APA） of messenger RNA （mRNA） are important contributors of transcriptome complexity, each playing a critical role in multiple biological processes. However, whether they have crosstalk and function collaboratively is unclear. We discovered that APA enriched in human sense-antisense （S-AS） gene pairs, and finally focused on RNASEH2C-KAT5 S-AS pair for further study. In cis but not in trans over-expression of the antisense KAT5 gene promoted the usage of distal polyA （pA） site in sense gene RNASEH2C, which generated longer 3＇ untranslated region （3＇UTR） and produced less protein, accompanying with slowed cell growth. Mechanistically, elevated Pol II occupancy coupled with SRSF3 could explain the higher usage of distal pA site. Finally, NAT-mediated downregulation of sense gene＇s protein level in RNASEH2C.KAT5 pair was specific for human rather than mouse, which lacks the distal pA site of RNASEH2C. We provided the first evidence to support that certain gene affected phenotype may not by the protein of its own, but by affecting the expression of its overlapped gene through APA, implying an unexpected view for understanding the link between genotype and phenotype.
基金
We thank Drs. Li Jin, Feng Qian, Jun Zhu and Hongjie Yao for constructive suggestions of this manuscript. The vectors of CRISPR/ Cas9 are the generous gifts from Drs. Yangming Wang and Yong- ming Wang. This work was supported by the National Basic Research Program （973 Program） （Nos. 2013CB530700 and 2015CB943000 to T. N.） and National Natural Science Foundation of China （Grant Nos. 31471192 and 31521003 to T. N.）.
