PgmNr D1523: Highly sensitive measurement of poly(A) tail by TAIL-seq2 reveals dynamic gene regulation via cytoplasmic polyadenylation during oogenesis.

Authors:
Ahyeon Son 1,2 ; Jaechul Lim 1,2 ; Mihye Lee 1,2 ; Hyeshik Chang 1,2 ; V. Narry Kim 1,2


Institutes
1) Center for RNA Research, Institute for Basic Science, Seoul, KR; 2) School of Biological Sciences, Seoul National University, Seoul, KR.


Keyword: next-generation sequencing

Abstract:

The tail of eukaryotic mRNA is subject to intensive modifications and critically influences mRNA stability and translatability. To investigate RNA tails at the genomic scale, we previously developed a method called TAIL-seq, but its low sensitivity precluded its applications to minute amounts of biological materials. In this study, we present a new version of TAIL-seq (TAIL-seq2) by incorporating splint ligation, which strongly enhances the sequencing depth for mRNAs (~1000 fold compared to that of the previous version). The improved method enabled us to investigate the regulation of poly(A) tail in oocytes and embryos. We discover that the cytoplasmic polyadenylation takes place mainly during late oogenesis in Drosophila, prior to fertilization. Mutation of wispy, a noncanonical poly(A) polymerase, abolishes polyadenylation, indicating that Wispy is likely to be the major, if not the sole, poly(A) polymerase in oocytes. Only ~5% of maternal transcripts (~143 genes) escape from cytoplasmic polyadenylation. By comparing with ribosome profiling data, we further find that mRNAs with elongated poly(A) tail become translationally active upon egg activation. Thus, the dynamic control of poly(A) tail in maturing oocytes pre-shapes the translatomic landscape of initiating embryos.



Flybase Genetic Index:
1. FlyBase gene symbol: wisp; FBgn: FBgn0260780