Find in Library

Insulin-like growth factor 1 (IGF1) plays an important regulatory role in the regulation of growth, differentiation, and anabolism in a variety of cells. In this study, the full-length cDNA of the <i>IGF1</i> gene was cloned from <i>Hyriopsis cumingii</i>, named <i>HcIGF1</i>. The expression level of <i>HcIGF1</i> in six tissues (adductor muscle, foot, hepatopancreas, gill, mantle, and gonad) was determined. In addition, the localization of <i>HcIGF1</i> in the mantle was analyzed by in situ hybridization, and finally the function of <i>HcIGF1</i> was explored by RNA interference and prokaryotic expression. The results showed that the amino acid sequence contained a typical IIGF structural domain. The phylogenetic tree showed that HcIGF1 clustered with other marine bivalve sequences. Quantitative real-time PCR and in situ hybridization analysis showed that <i>HcIGF1</i> was expressed in all tissues. The highest expression was in the foot and the lowest was in the mantle. In the mantle tissue, the hybridization signal was mainly concentrated in the outer mantle. After RNA interference, the expression of <i>IGF1</i> was found to be significantly decreased (<i>p</i> < 0.05), and its related genes <i>IGF1R</i>, <i>AKT1</i>, and <i>cyclin D2</i> were downregulated, while <i>MAPK1</i> were upregulated. The recombinant HcIGF1 protein was purified and its growth-promoting effect was investigated. The results showed that the recombinant HcIGF1 protein could significantly promote the proliferative activity of the mantle cells of mussels, with the best proliferative effect at 12.5 μg/mL. The results of this study provide a new method to solve the problem of weak proliferation of shellfish cells in vitro and lay the foundation for further understanding of the growth regulation mechanism of <i>H. cumingii</i>, as well as a better understanding of the physiological function of IGF1 in mollusks.