THE MALELESS PROTEIN ASSOCIATES WITH THE X-CHROMOSOME TO REGULATE DOSAGE COMPENSATION IN DROSOPHILA

The maleless (mle) gene is one of four known regulatory loci required for increased transcription (dosage compensation) of X-linked genes in D. melanogaster males. A predicted mle protein (MLE) contains seven short segments that define a superfamily of known and putative RNA and DNA helicases. MLE, while present in the nuclei of both male and female cells, differs in its association with polytene X chromosomes in the two sexes. MLE is associated with hundreds of discrete sites along the length of the X chromosome in males and not in females. The predominant localization of MLE to the X chromosome in males makes it a strong candidate to be a direct regulator of dosage compensation.