Sex‐specific expression of SOX9 during gonadogenesis in the amphibian Xenopus tropicalis

Abstract

To investigate the role of SOX9 gene in amphibian gonadogenesis, we analyzed its expression during male and female gonadogenesis in Xenopus tropicalis. The results showed that in both sexes SOX9 mRNA and protein were first detectable after metamorphosis when the gonads were well differentiated and remained present until the adult stage. In the testis, SOX9 expression was restricted to the nucleus of Sertoli-like cells, similarly to what has been observed in other vertebrates suggesting a conserved role in vertebrate testicular differentiation. In the ovary, in sharp contrast with what has been observed in all vertebrates examined so far, the SOX9 protein was localized in the cytoplasm of previtellogenic oocytes before being translocated into the nucleus of vitellogenic oocytes suggesting an unexpected role during oogenesis. These results suggest that the SOX9 gene may not be a sex-determining gene in X. tropicalis and may play different functions in testicular and ovarian differentiation. Developmental Dynamics 237:2996 -3005, 2008.

Dimorphic Expression of Various Transcription Factor and Steroidogenic Enzyme Genes during Gonadal Ontogeny in the Air-Breathing Catfish, <i>Clarias gariepinus</i>

“…In catfish female gonads, it was localized in the cytoplasm of the oocytes as reported earlier by Raghuveer and Senthikumaran [2010b]. In other teleosts, Sox9 protein was also detected in gonads of both males and females [Chiang et al, 2001;Yokoi et al, 2002;El Jamil et al, 2008]. Although its role is well defined in testis, it is not yet clear what exactly it does in ovary.…”

Sexing Frogs by Real-Time PCR: Using Aromatase <b><i>(cyp19) </i></b>as an Early Ovarian Differentiation Marker

“…In this frog species, both genetic and phenotypic sex can be determined [Miura et al, 1998], and gene expression levels in differentiating GMCs can be studied separately in genetic males and females. GMC gene expression patterns during sex differentiation have only been studied in a few other frog species, including Xenopus laevis [Semba et al, 1996;Koyano et al, 1997;Takase et al, 1999;Nakajima et al, 2000;Kawano et al, 2001;Lutz et al, 2001;Akatsuka et al, 2005;Osawa et al, 2005;Yoshimoto et al, 2006Yoshimoto et al, , 2008Urbatzka et al, 2007Urbatzka et al, , 2010Okada et al, 2009], Silurana ( Xenopus) tropicalis [El Jamil et al, 2008a;Duarte-Guterman and Trudeau, 2011], Engystomops ( Physalaemus) pustulosus [Duarte-Guterman et al, 2012] or Lithobates catesbeianus (formerly Rana catesbeiana ) [Mayer et al, 2002]. In these reports, 3 genes have consistently exhibited sexually dimorphic expression patterns in gonads of adult frogs and differentiating tadpoles.…”

Reprogramming of gene expression following nuclear transfer to theXenopusoocyte

“…Of particular interest is the question as to whether oocyte reactivates embryonic genes using a similar transcription factor set than those used in induced pluripotency. Indeed the oocyte contains large amounts of such transcription factors of the POU (Whitfield et al, 1993) and SRY-box (Sox) family (El Jamil et al, 2008) that could participate in gene reactivation. Alternatively gene reactivation could rely mainly on the oocyte specific components of the basal transcription machinery (TBP2, ALF) (D'Alessio et al, 2009).…”