Dynamic mRNA and miRNA expression analysis in response to intermuscular bone development of blunt snout bream (Megalobrama amblycephala)

Intermuscular bone (IB), which occurs only in the myosepta of lower teleosts, is attracting more attention because they are difficult to remove and make the fish unpleasant to eat. By gaining a better understanding of the genetic regulation of IB development, an integrated analysis of miRNAs and mRNAs expression profiling was performed on Megalobrama amblycephala. Four key development stages were selected for transcriptome and small RNA sequencing. A number of significantly differentially expressed miRNAs/genes associated with bone formation and differentiation were identified and the functional characteristics of these miRNAs/genes were revealed by GO function and KEGG pathway analysis. These were involved in TGF-beta, ERK and osteoclast differentiation pathways known in the literature to affect bone formation and differentiation. MiRNA-mRNA interaction pairs were detected from comparison of expression between different stages. The function annotation results also showed that many miRNA-mRNA interaction pairs were likely to be involved in regulating bone development and differentiation. A negative regulation effect of two miRNAs was verified through dual luciferase reporter assay. As a unique public resource for gene expression and regulation during the IB development, this study is expected to provide forwards ideas and resources for further biological researches to understand the IBs' development.