Steroids, aromatase and sex differentiation of the newt Pleurodeles waltlKuntz S. · Chardard D. · Chesnel A. · Grillier-Vuissoz I. · Flament S.
EA 3442 Génétique, Signalisation, Différenciation, Université Henri Poincaré, Nancy (France)
In the newt Pleurodeles waltl, genetic sex determination obeys female heterogamety (female ZW, male ZZ). In this species as in most of non-mammalian vertebrates, steroid hormones play a key role in sexual differentiation of gonads. In that context, male to female sex reversal can be obtained by treatment of ZZ larvae with estradiol. Male to female sex reversal has also been observed following treatment of ZZ larvae with testosterone, a phenomenon that was called the “paradoxical effect”. Female to male sex reversal occurs when ZW larvae are reared at 32°C during a thermosensitive period (TSP) that takes place from stage 42 to stage 54 of development. Since steroids play an important part in sex differentiation, we focussed our studies on the estrogen-producing enzyme aromatase during normal sex differentiation as well as in experimentally induced sex reversal situations. Our results based on treatment with non-aromatizable androgens, aromatase activity measurements and aromatase expression studies demonstrate that aromatase (i) is differentially active in ZZ and ZW larvae, (ii) is involved in the paradoxical effect and (iii) might be a target of temperature. Thus, the gene encoding aromatase might be one of the master genes in the process leading to the differentiation of the gonad in Pleurodeles waltl.
© 2003 S. Karger AG, Basel
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Supported by grants of the Université Henri Poincaré (BQR), of the Ligue Contre le Cancer, comités de la Meurthe et Moselle, de la Meuse et des Vosges and of the Association pour la Recherche sur le Cancer. S.K. is recipient of a grant from the French Ministère de la Recherche.
Received 30 May 2003;
revision accepted 23 June 2003.
Number of Print Pages : 6
Number of Figures : 3, Number of Tables : 0, Number of References : 28
Cytogenetic and Genome Research
Formerly ‘Cytogenetics and Cell Genetics’
Vol. 101, No. 3-4, Year 2003 (Cover Date: 2003)
Journal Editor: H.P. Klinger, Bronx, N.Y.; M. Schmid, Würzburg
ISSN: 1424–8581 (print), 1424–859X (Online)
For additional information: http://www.karger.com/journals/cgr