Homeotic gene silencing via chromatin modification. D. Huang. Inst Molecular Biol, Academia Sinica, Taipei, Taiwan, Republic of China.

   Homeotic genes located in the Bithorax and Antennapedia complexes specify the axial patterning of body segments. The expression domain of each homeotic gene is restricted to specific parasegments through development and requires two large groups of regulatory genes acting in an antagonistic manner. Among them, Polycomb (Pc), polyhomeotic and Posterior sex combs encode proteins that are constituents of large protein complex targeted to specific regulatory regions to silence homeotic genes via chromatin modification. We now present evidence to show that HDAC1, a Rpd3-like gene, interacts significantly with Pc to silence homeotic genes including Sex combs reduced, Ultrabithorax and Abdominal B. In addition, we have also found that HDAC1 copurify with Pc. These results strongly suggest that HDAC1 plays an important role in the Pc complex to silence homeotic genes.