MOLECULAR CHARACTERIZATION OF A SCLEROSTIN HOMOLOGUE IN BARBEL STEED (HEMIBARBUS LABEO) AND ITS RELATIONSHIP WITH INTERMUSCULAR BONE DEVELOPMENT

Previous studies have demonstrated that sclerostin (SOST) binds to and antagonizes the activity of bone morphogenetic proteins (BMPs). Because of the potential role of BMPs in intermuscular bone (IB) development, we explored the relationship between SOST and IB development. In this study, we identified a cDNA sequence encoding a SOST homologue in barbel steed (Hemibarbus labeo). Sequence analysis revealed that the SOST protein is composed of a signal peptide and a mature peptide which contained a C-terminal cystine knot-like domain. Phylogenetic tree analysis indicated that barbel steed SOST was closely related to goldfish (Carassius auratus) SOST. Expression of SOST transcripts were detected in all the tested tissues, with the highest transcript levels being found in the gill. in situ RNA hybridization results showed that SOST mRNA was obviously distributed in the myosepta. RT-qPCR showed that the transcript levels of the SOST gene significantly changed during the four developmental stages of IBs. This timing overlapped with IB formation, providing support for a role of SOST in IB development.