Identification and expression of HDAC4 targeted by miR-1 and miR-133a during early development in Paralichthys olivaceus

Histone deacetylase 4, which is a class II histone deacetylase, plays a critical role in development, differentiation of muscle, cell proliferation and metabolism. In our study, we obtained the full-length HDAC4 cDNA, which included the coding region of 3171 bp, a 180 bp 5′untranslated region (UTR) and a 760 bp 3′UTR. The deduced HDAC4 protein contained all known functional domains identified in other organisms. The phylogenetic analysis indicated that Paralichthys olivaceus HDAC4 had the highest identity with the Takifugu rubripes. Tissue distribution analysis indicated that HDAC4 is abundantly expressed in muscle, and its levels are significantly higher in muscle than in other tissues (P < 0.01). HDAC4 mRNA levels at 3 dph (days post hatching) and 36 dph were higher than that in other stages. Exogenous thyroid hormones either directly or indirectly promoted the expression of HDAC4 mRNA during metamorphosis, indicating that HDAC4 might directly or indirectly be regulated by thyroid hormone during muscle development in metamorphosis. To identify the miRNAs targeting HDAC4, we performed a luciferase reporter assay and verified that HDAC4 is a common target gene of miR-1 and miR-133a indicating that HDAC4 might be involved in a signal pathway of microRNA regulating muscle development.