Sox9a, not sox9b is required for normal cartilage development in zebrafish

摘要

Sox9 is a multifunctional gene and plays crucial roles in vertebrate development including chondrogensis. In teleost, due to the genome duplication event, there are two co-orthologs sox9a and sox9b . In this study, CRISPR/Cas9 technology was performed to disrupt the function of either sox9a or sox9b . All sox9a mutants ( sox9a Δ10 and sox9a Δ67) and sox9b mutants ( sox9b Δ11 and sox9b Δ20) lost HMG domain and Q/S domain, however, only sox9a mutant larvae had mis-shaped pectoral fins and lacked the scapulocoracoid cartilage. sox9b mutant larvae showed normal cartilages similar to wild type larvae. The results suggested that sox9a , not sox9b was required for cartilage development in zebrafish, which was different from the sox9b -mutant phenotype induced by N-ethyl-N-nitrosourea (ENU) treatment, gamma radiation treatment or morpholino injection. This study confirmed that ancestral sox9 gene functions partitioned between the two paralogs in zebrafish.