THE HUMAN TESTIS-DETERMINING FACTOR SRY - A NEW MEMBER OF THE HMG BOXPROTEIN FAMILY

The product of the sex-determining gene SRY is a member of the HMG box containing protein superfamily. The HMG box is a DNA-binding domain o f about 80 amino acids shared by many proteins with diverse functions. It seems that the functions of the full length protein are restricted to the HMG box but their molecular basis remains to be determined. We have summarized here the properties of this binding domain described so far in the literature and, using a synthetic peptide mimicking the DNA binding domain (SRY80), we have confirmed the existence of DNA min or groove contacts with this domain. Using intrinsic fluorescence of t he tryptophane, the interaction between SRY80 and the putative target sequence AACAAAT was also quantified. In conclusion, we also consider the possible putative action of SRY to fullfil its role in sex determi nation.