AUTHOR=Liu An , Liu Jing , Liu Fang , Huang Yiyue , Wang Guizhong , Ye Haihui 

TITLE=Crustacean Female Sex Hormone From the Mud Crab Scylla paramamosain Is Highly Expressed in Prepubertal Males and Inhibits the Development of Androgenic Gland

JOURNAL=Frontiers in Physiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.00924

DOI=10.3389/fphys.2018.00924

ISSN=1664-042X

ABSTRACT=<p>Recently, the crustacean female sex hormone (CFSH), which is considered a female-specific hormone, has been shown to play a crucial role in female phenotypes in crustaceans. In this study, two transcripts (<italic>Sp-CFSH1</italic> and <italic>Sp-CFSH2</italic>) encoding the same CFSH precursor were cloned from the mud crab <italic>Scylla paramamosain</italic>. Homology and phylogenetic analysis showed that CFSHs were homologous to interleukin-17 and highly conserved among brachyuran crabs. PCR analysis revealed that <italic>Sp-CFSH</italic> was expressed exclusively in the eyestalk ganglion of both prepubertal males and females, and surprisingly, the abundance of <italic>Sp-CFSH</italic> transcripts detected in the males were not significantly different from that of the females (<italic>P</italic> &gt; 0.05). In addition, mRNA <italic>in situ</italic> hybridization showed that <italic>Sp-CFSH</italic> was localized in the X-organ of the male eyestalk ganglion. During the development of the androgenic gland (AG), the level of <italic>Sp-IAG</italic> mRNA in AG remained at low levels from stages I to II (early stage) but had a significant increase at stage III (mature stage). In contrast, the level of <italic>Sp-CFSH</italic> transcripts in the eyestalk ganglion was high in the early stage but extremely low in the mature stage. To investigate the potential function of CFSH in male <italic>S. paramamosain</italic>, the recombinant protein (∼20 kDa) was expressed in <italic>Escherichia coli</italic> and was subsequently added to AG explants <italic>in vitro</italic>. It was demonstrated that recombinant <italic>Sp-CFSH</italic> protein significantly reduced the expression of <italic>Sp-IAG</italic> in the AG explants at a concentration of 10<sup>−6</sup> M (<italic>P &lt;</italic> 0.05). In conclusion, our study provides the first piece of evidence that shows CFSH from the eyestalk ganglion acts as a negative regulator inhibiting the development of AG in crustaceans.</p>