The human SRY protein is present in fetal and adult Sertoli cells and germcells

Sex determination in mammals is controlled by the Y chromosome located SRY gene. Despite recent advances towards understanding the mechanisms that reg ulate sex determination in mammals, the expression profile of the SRY prote in in human tissues is unknown. To localize the SRY protein and determine i ts cellular distribution, we prepared monoclonal antibodies (mAb) against t he recombinant SRY protein. One antibody, LSRY1.1, recognizes a SRY-specifi c epitope and was used to localize the protein in different cells and tissu es. The mAb recognizes a protein of 27 kDa in total lysates of HeLa SRYB3 c ells. Immunocytochemical staining showed a nuclear localization of the prot ein. Immunohistochemical studies performed on gonadal tissue of a fetus, a one month-old boy and an adult man, demonstrated the presence of SRY protei n in the nucleus of Sertoli and germ cells. In addition two 46,XX SRY(+) ma les had the SRY protein in their gonadal tissues. Ail other samples were ne gative, Including all female tissue studied and the testis of a 46,XX SRY(- ) male. The presence of SRY protein in fetal and adult gonadal tissues incl uding germ cells suggests that SRY may have other male-specific functions i n addition to sex determinism.