Dimorphic expression of dmrt1 and cyp19a1 (ovarian aromatase) during early gonadal development in pejerrey, Odontesthes bonariensis.

JUAN IGNACIO FERNANDINO; RICARDO HATTORI; TAKAHIRO SHINODA; HIROYUKI KIMURA; PABLO STROBL MAZZULLA; CARLOS AUGUSTO STRÜSSMANN; GUSTAVO M SOMOZA

Sexual Development

Karger

Año: 2008 vol. 2 p. 316 - 324

1661-5425

The pejerrey (Odontesthes bonariensis) is a teleost fish with strong temperature-dependent sex determination (TSD).  Several studies have shown that dmrt1 and gonadal aromatase (cyp19a1) are implicated in the sex differentiation process in teleosts but little is known on the expression balance and endocrine regulation of these two genes during TSD.  This study was designed to clarify the expression patterns of both genes during gonadal sex differentiation of pejerrey reared at female-, male- and mixed-sex- producing temperatures (FPT, MPT and MixPT respectively).  The expression of dmrt1 was found to be significantly higher during gonadal sex differentiation at MPT compared to FPT.  Conversely, cyp19a1 expression clearly increased during differentiation at FPT but not at MPT.  The expression of both genes at MixPT showed a dimorphic profile with individual values resembling either those at the MPT or FPT.  Administration of exogenous 17â-estradiol down- and up-regulated the expression of dmrt1 and cyp19a1, respectively, regardless of temperature, and rescued the female phenotype at the MPT.  However, treatment with the aromatase inhibitor Fadrozole caused masculinization without changing the pattern of gene expression.  These results are strong evidence of the involvement of both genes in the gonadal differentiation process of pejerrey.  The involvement of estradiol is discussed.