MURDOCK, C*; WIBBELS, T: Steroidogenic factor-1 mRNA levels in the embryonic adrenal/kidney/gonadal complexes of Trachemys scripta

The red eared slider turtle, Trachemys scripta, has been the focus of many temperature-dependent sex determination (TSD) studies in the past. Many of these previous studies have suggested that endogenous estrogen production during development is a key event in the sex determination process. Due to these findings, the expression patterns of steroidogenic enzymes involved in estrogen biosynthesis are of particular interest. Steroidogenic factor-1 (SF-1) has been shown to regulate the transcription of the P450 hydroxylases (including aromatase) involved in steroidogenesis and, therefore, is a potential factor in the TSD cascade. The cDNA for T. scripta SF-1 was previously cloned in our laboratory and the sequence data were used so that an RNA competitor molecule for SF-1 could be produced. This RNA competitor was then used to develop a quantitative competitive RT-PCR for SF-1. These quantitative competitive RT-PCRs were performed on total RNA isolated from embryonic adrenal/kidney/gonadal complexes taken at both male- and female-producing temperatures at stages 15, 17, 19, 21, and at hatching. The results provide an overview of the pattern of SF-1 expression during TSD in T. scripta.