Clone of Decoding the post-transcriptional regulatory code during embryogenesis
Speaker: Antonio J. Giráldez, PhD - Genetics Department, Yale University School of Medicine. New Haven CT (USA)
Organizer: IRB Barcelona
Date: Tuesday, March 21st 11.00h.
Place: Auditorium, Parc Científic de Barcelona, Spain
Host: Marco Milán - IRB Barcelona
Post-transcriptional regulation plays a fundamental role in shaping gene expression after fertilization across animals, a period where the embryo is acquiring totipotency. To understand the post-transcriptional regulatory code that shapes mRNA decay and translation regulation during this maternal to zygotic transition we have combined three approaches: i) RESA, a novel RNA Element Selection Assay which quantifies the regulatory activity of sequences in the 3’UTR and the CDS throughout the trasncriptome in vivo. ii) Interactome capture, to identify the proteins involved and iii) Parallel iClip for 30 RNAbinding proteins to define their regulatory targets and motifs during development.
These approaches have provided three major insights into the regulatory landscape during embryogenesis. First, we have identified that individual codons shape mRNA stability through deadenylation, an effect that is conserved from drosophila to mammals during the maternal-to-zygotic transition. Second, we have identified common regulatory sequences in the 3’UTR and the CDS that have antagonistic effects in mRNA stability. We find that overall, 3’UTR regions confer stability, with the most prominent exception of miRNA target sites. In contrast, coding sequences confer destabilization. We identified that sequence bias composition explains part of this regulation, but in addition, we identified motifs that are associated with increased and decreased stability of the mRNA in vivo. Finally, to define the set of regulatory proteins in vivo, we have undertaken interactome capture identifying 170 proteins that are associated with mRNAs during this transition. Parallel iClip analysis for 30 of these proteins revealed a binding map and their regulatory motifs in vivo. Comparing the iClip analysis with the identification of regulatory motifs in vivo revealed a combinatorial code that mediate mRNA stability and decay during the maternal to zygotic transition.
Extraordinary Cell and Developmental Biology Seminar