AUTHOR=Tang Meizhen , Lu Zhijie , Babu Sarath V , Yang Guang , Li Yanan , Xu Zizheng , Pan Gan , Qin Zhendong , Lin Li 

TITLE=The Regulatory Relationships Between the Gonad-Inhibiting Hormone and Insulin-Like Androgenic Gland Hormone-Binding Protein Genes in the Eyestalk-Androgenic Gland-Testis Axis of Macrobrachium rosenbergii

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.775191

DOI=10.3389/fmars.2021.775191

ISSN=2296-7745

ABSTRACT=Gonad-inhibiting hormone (GIH) belongs to a family of neuropeptides that are released from the eyestalks of male crustaceans and plays key roles in gonadal maturity, reproduction and molting. However, the detailed mechanisms underlying the effects of GIH on sexual regulation have yet to be elucidated. In the present study, we aimed to demonstrate how GIH can mediate the activity of the androgenic gland (AG). To do this, we cloned and characterized the GIH sequence from Macrobrachium rosenbergii (MrGIH). The open reading frame (ORF) of MrGIH was 360 bp and codes for a polypeptide of 119 amino acids and a putative protein of 13.56 KDa. Tissue analysis showed that MrGIH is widely expressed in a range of tissues but particularly, the eyestalk, intestine, and nerve cord. Following the dsRNA silencing of MrGIH for 24 h, the expression levels of MrGIH were down-regulated in both the eyestalk and AG when compared with the negative control, but significantly increased the expression of Macrobrachium rosenbergii insulin-like androgenic gland hormone-binding protein (MrIAGBP), thus suggesting that MrGIH is an inhibitory factor for MrIAGBP. In addition, we found that eyestalk removal on certain days led to increased expression levels of MrIAGBP expression. The expression levels of MrIAGBP peaked at 2 d in the AG after unilateral and bilateral eyestalk ablation, exhibiting a 7.27- and 6.03-fold increase, respectively. Immunohistochemistry assays further confirmed that MrGIH is an inhibitory factor that can negatively regulate gonadal development and maturation. Collectively, our findings provide new insights into the mechanisms that control the gonad-inhibiting signaling pathway during the sexual differentiation of male M. rosenbergii. Furthermore, our data provide options for a new means of controlling gender in M. rosenbergii and other decapodal crustaceans.