Comparative transcriptome analysis between muscle and swim bladder reveals key genes regulating collagen deposition in zebrafish

Abstract

Collagens are the most abundant extracellular matrix (ECM) proteins, which play important role in maintaining muscle texture of fish. Appropriate enhancement of tissue collagen deposition would improve quality of fish products. However, the regulatory mechanism of tissue collagen deposition remains poorly understood in fish. Here, we reported a comparative investigation on collagen deposition, transcriptional profile of collagen and their regulatory genes between muscle and swim bladder in zebrafish. Moreover, the function of key regulatory genes was investigated in vitro. Results indicated that collagen content in swim bladder was much higher than that in muscle. Transcriptome analysis identified 7351 differentially expressed genes and enrichment of ECM-related functional terms. The expression level of 26 collagen genes was significantly higher in swim bladder, including 5 of 8 highly-expressed genes (col1a1a, col1a2, etc.). Besides, most putative collagen regulatory genes (20/24) have higher expression level in swim bladder. Protein-protein interaction network analysis indicated that mmp2, p3h, ctgfa, serpinh1a have close interaction with col1 genes (col1a1a, col1a2). Over-expression of ctgfa and serpinh1a significantly promoted transcription of col1 genes and increased collagen I content in zebrafish fibroblast. It’s concluded that transcriptional signature of collagen genes varies between tissues and is differentially regulated by collagen regulators. Our data provides novel insights into the regulatory mechanism of tissue collagen metabolism and key molecular targets for regulating collagen deposition in fish during aquaculture practice.