Characterization and sexual dimorphic expression of Cytochrome P450 genes in gonads of the sea urchin (Mesocentrotus nudus)

Sea urchin (Mesocentrotus nudus) is a commercially significant mariculture species, with its gonads being the exclusive edible parts for humans. Identifying sex-related genes is an effective approach for elucidating the underlying molecular mechanisms of gonad development in sea urchins. Some cytochrome P450 (CYP) superfamily members play critical roles in sex differentiation, steroid hormone biosynthesis, and ovarian steroidogenesis. In the present study, we identified 83 CYPs assigned to 17 families from the gonadal transcriptomic data of M. nudus, with most CYPs clustering within the CYP 2 family branches. Furthermore, we identified 11 gender-biased CYPs, including CYP 17A1, CYP 2, CYP 3A24, CYP 4V2, and CYP 46A1, as well as 11 CYPs related to steroid hormone biosynthesis, including CYP 1A1, CYP 1A5, CYP 3, and CYP 17A1. The expression patterns of those candidate sex-related CYP genes were also analyzed. The findings lay the foundation for further investigating the role of CYPs in the endogenous synthesis of sex steroids, offering valuable insights into the molecular mechanisms underlying sex differentiation in sea urchins.