Essential role of Drosophila Hdac1 in homeotic gene silencing

Deacetylation of the N-terminal tails of core histones plays a crucial role in gene silencing. Rpd3 and Hda1 represent two major types of genes encodi ng trichostatin A-sensitive histone deacetylases. Although they have been w idely found, their cellular and developmental roles remain to be elucidated in metazoa. We show that Drosophila Hdac1, an Rpd3-type gene, interacts co operatively with Polycomb group repressors in silencing the homeotic genes that are essential for axial patterning of body segments. The biochemical c opurification and cytological colocalization of HDAC1 and Polycomb group re pressors strongly suggest that HDAC1 is a component of the silencing comple x for chromatin modification on specific regulatory regions of homeotic gen es.