Developmental functions ofrapgef1bin neural crest specification and presomitic mesoderm patterning

Abstract

Rapgef1, a cell fate determinant and effector of multiple signaling events is essential for mammalian embryonic development. Here, we investigated the developmental role of rapgef1 using zebrafish embryos as a model. We show that rapgef1 is maternally expressed and alternately spliced isoforms of its two paralogs rapgef1a and rapgef1b show development and tissue-specific expression. CRISPR-Cas9 and morpholino-based targeting of rapgef1b resulted in developmental defects in the embryonic brain and somites. The rapgef1b morphants showed altered expression of lineage determinants of the cranial neural crest. Transcriptome and in-depth gene expression analysis of morphants revealed fresh insights into the developmental functions of rapgef1b in presomitic mesoderm, and somitogenesis. During early embryonic mitoses, the morphants showed mitotic defects such as diffused spindle poles and chromosome mis-congression. Our results demonstrate that rapgef1b is required for normal embryonic mitoses, cranial neural crest specification, somitogenesis, and myogenesis during embryonic development.