Insight into the Regulatory Relationships between the Insulin-Like Androgenic Gland Hormone Gene and the Insulin-Like Androgenic Gland Hormone-binding Protein Gene in Giant Freshwater Prawns ().

Giant freshwater prawns () are commonly found throughout the world. The size of the male giant freshwater prawn is much larger than that of the female. Therefore, understanding the molecular mechanism that underlies the sexual differentiation of is of both commercial and scientific importance. Insulin-like androgenic gland hormone (IAG) plays a key role in the differentiation of sex in . Although IAG has been investigated, the regulatory relationship between IAG and its binding protein partner, the insulin-like androgenic gland hormone-binding protein (IAGBP), has not been studied in . Here, we cloned and characterized the from () for the very first time. Transcriptomic analysis showed that mRNA was detected in a wide array of tissues with the highest expression found in the androgenic gland. The importance of in male development was further demonstrated by an increase in transcripts during the development of the androgenic gland and was only highly transcribed in the androgenic gland of . Interestingly, we found that the gene expression started during the 20th-day larva after hatching stage (LH20), followed (20th-day post-larval stage, PL20) by a gradual elevation of levels. The levels of both genes peaked at the adult stage. The relationship between - and - was further analyzed using RNA interference. The injection of double-stranded RNA (dsRNA) significantly reduced the transcription of , while the amount of mRNA and the translation of IAGBP protein was significantly reduced by the injection of - dsRNA. These results revealed that IAGBP is involved in IAG signaling. Furthermore, our data supports the hypothesis that (IAG and IAGBP)-IAG receptor signaling schemes exist in . Our results will provide important information for the further study of determining the sex of .