Maintenance of gonadal differentiation into testis in the absence of SRY expression in mammals- A review

Abstract

Expression of the SRY gene by somatic cells induces the differentiation of primordial germ cells and cells of uncommitted gonad into male gametes (Testis). If expression of Sex Determining Region of Y-chromosome (SRY) gene is impaired the primordial germ cells and cells of uncommitted gonad differentiate into female (ovary). In male pathway the SRY gene is seen to up-regulates SRY-Box 9 (Sox9). Although this gene is limited to a certain period of time, there are other factors which regulate Sox9 such as Fibroblast Growth Factor 9 (Fgf9) and prostaglandin D2 (Pgd2). Furthermore, factors such as Fibroblast Growth Factor 9 (Fgf9), Pgd2, Steroidogenic factor 1 (Sf1), Sox8, Neurotrophin 3 (NTF3), homolog of Drosophila polycomb genes (M33), Anti-Mullerian Hormone (AMH) and Double sex and mab-3 related transcription factor 1 (DRMT1) are responsible for male sex determination. The female pathway is rather a default with factors like R-Spondin 1(Rspo1), Wnt Family Member 4 (Wnt4), anti-testis gene (DAX1), Forkhead Box L2 (FOXL2) and Sox3 being involved. The present review paper describes the differentiation of the primordial germ cells and cells in uncommitted gonad into male gametes in the absence of SRY gene expression.

Key words: Ovary, Sex determination, SRY gene, Testis