DEV2011 Lecture Notes - Lecture 13: Dax1, Sertoli Cell, Sox9
Document Summary
Sex determination is the initial event that determines whether the gonads will develop as testes or ovaries. Xy system in mammals: sex is determined by presence of y. female is the default sex; due to the absence of the y. The combination of sex chromosomes that determine the sex of an offspring; in humans the sex chromosomes of a normal female are xx and the sex chromosomes of a normal male are xy. Sry is a sex-determining gene on the y chromosome. Sry initiates testis differentiation by activating male-specific transcription factors that allow these bipotential cells to differentiate and proliferate. Sry accomplishes this by upregulating sox9, a transcription factor with a dna-binding site very similar to. Sox9 in turn upregulates fibroblast growth factor 9 (fgf9), which is necessary for proper sertoli cell differentiation. Sox9 can also upregulate itself by binding to its own enhancer region (positive feedback loop).