Probing RNA-protein interactions in the early embryo

In recent years, advances in ultra-low input genome-wide methods have enabled systematic analyses of mRNA abundance, and of chromatin organization, throughout early development in a variety of model systems.

Here, we extend these efforts to the study of RNA binding protein (RBP) function in early mouse embryos, adapting REMORA based on fusing an RNA-editing enzyme to an RBP of interest – for use in early embryos. We benchmark our approach for several well-studied RBPs, successfully recovering expected features of their RNA cargos, and overall surveyed the RNA cargos for 17 RBPs of interest for early gene regulation. Analysis of changes in mRNA metabolism following knockdowns of the RBPs surveyed here allowed us to define direct regulatory functions for a subset of RBPs in the early mammalian embryo, including an unanticipated role for the RNA export factor Alyref in control of 3’ polyadenylation sites.