Knockdown of two splice variants of Ca2+/calmodulin-dependent protein kinase Iδ causes developmental abnormalities in zebrafish, Danio rerio

► The functional roles of CaMKIδ in vivo have not been fully clarified yet. ► In this study, we cloned and characterized two splice variants of zebrafish CaMKIδ. ► Both isoforms showed a different temporal and spatial expression pattern in zebrafish. ► The knockdown of the zCaMKIδ genes resulted in an increase of abnormal embryos with small heads. ► This phenotype was rescued by coinjection with recombinant zCaMKIδ but not with kinase-dead mutant.