Sexually dimorphic expression of co-repressor Sin3A in mouse kidneys

Using Western blot analysis we found transcriptional co-repressor Sin3A to be expressed at a higher level in male mouse kidney than in females. HDAC1 (histone deacetylase 1) protein, another co-repressor forming complexes with Sin3A, was not higher in males. No sex differences in Sin3A expression were found after gonadectomy, suggesting that gonadal secretions in adulthood cause the sex difference in kidney expression of Sin3A. In contrast, HDAC1 levels were higher in castrated gonadal males than in females, which presumably reflects a long-lasting differentiating effect of testicular secretions in early development on this protein in kidneys. In gonadectomized mice in which sex chromosome complement (XX vs. XY) is independent of gonadal type (testes vs. ovaries), there was no difference in the level of Sin3A or HDAC1 expression in kidney in XX or XY mice of the same gonadal sex.