Developmental phenotypes of yap, taz and grb10a, grb10b zebrafish mutants

Yes Associated Protein (YAP) and its paralog Transcription co-Activator with PDZ domain (TAZ) are the effectors of the growth restricting hippo pathway. Their roles in organ growth, stem cell maintenance and cancer pathophysiology are well studied. However, the roles of YAP and TAZ in early development are not well understood. In this study we characterised double yap-/-:taz-/- zebrafish mutants using various method including expression studies by in situ hybridisation and immunostaining. We showed defective floor plate formation in the double mutant. The neural crest cells were decreased and their pigment derivatives in the trunk were almost absent while in the head specification and/or migration of a subset of cranial neural crest was defective. Novel roles for yap and taz in the floor plate induction and neural crest cells specification are proposed in this study.
Growth factor Receptor Bound Protein 10 is an imprinted gene that is known to function as a growth repressor in mouse and mammalian cells cultures by antagonising insulin signalling. The role of Grb10 in early development is not known. In this project, we characterised two grb10 zebrafish mutants: grb10a and grb10b. Zebrafish has two copies of Grb10. In this project, we found no evidence of a visible phenotype in the single grb10a or grb10b mutants. Further study of the double mutant, to eliminate redundancy effect, showed no detectable embryonic phenotype.