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Searching for sex determining genes regulated by SOX9
Author(s) -
Kelly Sabine,
Harley Vincent R
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a78-a
Subject(s) - sox9 , testis determining factor , gonadal ridge , biology , gene , transactivation , gonad , sex reversal , sexual differentiation , genetics , gene expression , embryonic stem cell , y chromosome , endocrinology
The human embryonic genital ridge is initially bipotential with the transcription factor SOX9 (SRY related HMG box 9) being necessary and sufficient for its differentiation into a testis. SOX9 has two testis gene targets, Anti Mullerian Hormone and Vanin1 . However, these targets are not essential for human testis formation. Therefore SOX9 must regulate other genes that are essential for testis formation and that these target genes may be ‘new’ sex determining genes. It is hypothesized that other human SOX9 target genes exist which are upregulated in the XY gonad and which cause sex reversal when mutated. The aim of this study is to identify new target genes of SOX9 which are involved in sex determination. To identify novel target genes, SOX9 was overexpressed in human NT2/D1 embryonal testicular cells to mimic SOX9 upregulation which occurs during early male sex determination prior to testis cord formation. A panel of male and female‐specific genital ridge expressed genes was screened by RT‐PCR for gene expression changes in cells overexpressing SOX9. Three male specific genes were elevated. Double immunohistochemistry and image analysis showed that protein levels encoded by these genes were elevated in SOX9 transfected cells, thus validating the RNA results. RNA levels of Sox9 target genes will be measured in gonads from sex reversed XY Sox9 knockout and XX Sox9 transgenic mice. Bioinformatic analysis of target gene regulatory regions reveal conserved SOX binding sites and transactivation studies using luciferase reporter constructs bearing these regions are in progress. These studies indicate three new SOX9 target genes which all show elevated mRNA gene expression and protein expression in response to SOX9 overexpression. Research Support: NHMRC (Aust), Monash University Scholarship