Role of Cyp19a1 in the female pathway of a freshwater turtle species(Mauremys reevesii)with temperature-dependent sex determination

摘要

The molecular mechanisms underpinning temperature-dependent sex determination(TSD)in reptiles have attracted great biological interest for many years.However,which genetic factors are essential for TSD remain elusive,especially regarding female sex determination.Cytochrome P450 family 19 subfamily A member 1(Cyp19a1)encodes the endoplasmic reticulum enzyme aromatase,which participates in the catalytic conversion of androgens to estrogens,and is implicated in sexual differentiation in many species.However,whether Cyp19a1 plays a critical role in determining gonadal sexual fate in TSD species remains to be elucidated.In the current study,Cyp19a1 exhibited a temperature-dependent and sexually dimorphic expression pattern,preceding gonadal sex differentiation in a TSD turtle species(Mauremys reevesii).Sexual phenotype of the turtles was successfully reversed by aromatase inhibitor treatment at the female-producing temperature(FPT).Furthermore,exogenous estradiol(E2)treatment led to complete male-to-female sex reversal at the male-producing temperature(MPT),accompanied by rapid up-regulation of Cyp19a1.Thus,Cyp19a1 appears to be essential for female sex determination in M.reevesii,suggesting a vital role in the female TSD pathway.