DMRT1 prevents female reprogramming in the postnatal mammalian testis

The presence or absence of the Y-chromosome gene Sry determines whether precursor cells differentiate into testicular Sertoli cells or ovarian granulosa cells in the mammalian fetus. Loss of the transcription factor FOXL2 in the adult ovary can lead to transdifferentiation of granulosa cells into Sertoli cells, but in males the sex-determining decision was thought to be stable. This study shows that this is not the case: adult mouse testicular cells become ovarian cells if the Dmrt1 gene is lost. In the absence of transcription factor DMRT1, FOXL2 is activated and Sertoli cells are reprogrammed as granulosa cells.