Molecular and functional characterization of the ovarian development associated transcription factor ZGLP1 in the marine fish four-eyed sleeper (Bostrychus sinensis)

Sex determination is a fundamental process governed by genetic hierarchies of transcription factors. Zinc finger GATA like protein-1 (ZGLP1) is an important female determining factor in mammals, but its function is remained unclear in teleost fish. Four-eyed sleeper ( Bostrychus sinensis ) is a commercial fish, exhibiting significant sexual dimorphism with males possessing significant advantages in body size and growth rate. Therefore, developing the sex control breeding strategy to produce all-male populations will be highly valuable. Previous finding indicated that B. sinensis Zglp1 ( BsZglp1 ) is an ovary-biased gene during early development in four-eyed sleeper, we further investigated its functional roles and regulatory interactions. BsZglp1 encodes a 523-amino-acid protein containing two zinc finger domains (ZNFs) and two nuclear localization signals (NLSs), which had a close relationship with other teleost Zglp1 orthologs. Expression analysis demonstrated that BsZglp1 was specifically localized to early oocytes. Overexpression of BsZglp1 in primary culture of testicular cells enhanced the expression of endogenous BsFoxl2 and BsCyp19a and suppressed the expression of BsDmrt1 and BsAmh , whereas knockdown of BsZglp1 in ovarian cells resulted in opposite effects. Functional assays revealed that BsZglp1 transcriptionally activated female-pathway genes ( BsFoxl2 and BsCyp19a ) by ZNF2 domain while repressed male-pathway genes ( BsDmrt1 and BsAmh ) by ZNF1. Furthermore, we found a reciprocal repression among BsZglp1 and BsDmrt1 as well as BsSox9 . Our results established BsZglp1 as a crucial regulator in four-eyed sleeper ovary development; it might promote ovarian differentiation and inhibit testicular differentiation by mutual antagonism with key male differentiation associated genes. These results suggested that BsZglp1 is a promising gene editing target for generating all-male populations in this commercially important species. • BsZglp1 is an oocyte specific transcription factor in four-eyed sleeper. • BsZglp1 is capable of activating transcription of BsFoxl2 and BsCyp19a . • BsZglp1 mutually antagonizes with testis differentiation genes BsDmrt1 and BsSox9. • BsZglp1 regulates female and male pathway genes through distinct Znf domains.