Multiple Approaches to Study of Steroidogenic Factor 1 : Identification of a Novel Regulatory Element and Identification of Novel Target Genes
Steroidogenic Factor 1 (SF-1) is an essential component of the hypothalamic-pituitary-adrenal-gonadal axis. SF-1 knockout (KO) mice lack adrenals, gonads, the ventromedial hypothalamic nucleus (VMH), and pituitary gonadotropes. SF-1 is a transcription factor implicated in the regulation of many genes important in endocrine function. Research into the regulation of SF-1 expression, mostly focused on the proximal promoter, has been unable to fully explain the expression pattern of SF-1. I used DNase hypersensitivity mapping to search for novel regulatory regions of the SF-1 genomic region. One region between the 6th and 7th exons of SF-1 had tissue specific DNase I hypersensitivity. Analysis of this region revealed high conservation with the human genomic sequence and a smaller region that was also highly conserved in the chicken genomic sequence. Transient transfection assays and electrophoretic mobility shift assays have been employed to investigate this conserved element for enhancer activity. Numerous genes are target genes of SF-1, yet loss of known target genes fail to explain why the adrenals, gonads and VMH fail to develop in SF-1 KO mice. I used an SF-1/eGFP transgene as a reporter in both WT and KO E16.5 embryos. eGFP+ cells from the developing VMH of these mice were collected through the use of FACS. Several potential target genes of SF-1 have been identified and analysis of these genes is an ongoing project.