Multi-level transcriptional regulation of embryonic sex determination and dosage compensation by the X-signal element .

The nuclear hormone receptor is known to be an embryonic X-signal element that represses , the sex-switch gene that is the master regulator of sex determination and dosage compensation. Several prior studies on function have suggested that may have additional downstream roles beyond the regulation of expression. In this study we characterize some of these additional roles of in regulating the dual processes of sex determination and dosage compensation during embryogenesis. Our study reveals that acts on many of the downstream targets of in a -independent manner. Further analysis of these shared but independently regulated downstream targets uncovered that mediates the expression of hermaphrodite- and male-biased genes during embryogenesis. We validated binding on one of these downstream targets, the male-developmental gene . Our data suggests a model where exhibits multi-level direct transcriptional regulation on several targets, including and genes downstream of to reinforce the appropriate expression of sex-biased transcripts in XX embryos. Furthermore, we found that double mutants show defects in dosage compensation. Our study provides evidence that misregulation of , one of the components of the dosage compensation complex, and the subsequent misregulation of H4K20me1 enrichment on the X chromosomes, may contribute to this defect.