Abstract

The androgenic gland (AG) is a male-specific endocrine organ that controls the primary and secondary sexual characteristics in male crustaceans. More evidence indicates that the insulin-like androgenic gland hormone gene (IAG) is the key male sexual differentiation factor, particularly the application of RNA interference (RNAi) technology onIAG. In this study, the full-length cDNA ofIAG(termedPcIAG) was isolated from the red swamp crayfish,Procambarusclarkii. Tissue distribution analysis showed that in addition to its expression in the AG of maleP. clarkii,PcIAGwas widely expressed in female tissues and other male tissues. The PcIAG protein was detected in the reproductive and nervous systems of adult maleP. clarkii. Additionally, RNAi results showed that thePcIAGexpression could be silenced efficiently, and the male sperm maturation and release possibly present a transient adverse interference at lower doses (0.1 μg/g and 1 μg/g) of PcIAG–dsRNA (PcIAGdouble-stranded RNA). Dramatically, the expression level ofPcIAGincreased sharply shortly after the injection of higher doses (5 μg/g and 10 μg/g) of PcIAG–dsRNA, which might accelerate the maturation and release of sperm. Moreover, the expression ofPcSxl(P. clarkii Sex-lethal) was detected by Quantitative Real-Time PCR (qPCR) after the injection of PcIAG–dsRNA to explore whether thePcIAGgene regulates thePcSxlgene, and we found that thePcIAGdid not directly regulatePcSxlinP. clarkii. The study could help accelerate the progress ofPcIAGfunctional research and provide a useful reference for the single-sex selective breeding ofP. clarkii.Keywords:IAG;sexual differentiation;RNAi;Procambarus clarkii;Sxl