The Polycomb group loci in Drosophila encode chromatin proteins required for repression of homeotic loci in embryonic development. We show that mouse Polycomb group homologues, RAE28, BMI1 and M33, have overlapping but not identical expression patterns during embryogenesis and in adult tissues. These three proteins coimmunoprecipitate from embryonic nuclear extracts. Gel filtration analysis of embryonic extracts indicates that RAE28, BMI1 and M33 exist in large multimeric complexes. M33 and RAE28 coimmunoprecipitate and copurify as members of large complexes from F9 cells, which express BMI1 at very low levels, suggesting that different Polycomb group complexes can form in different cells. RAE28, BMI1 and M33 interact homotypically, and both RAE28 and M33 interact with BMI1, but not with each other. The domains required for interaction were localized. Together, these studies indicate that murine Polycomb group proteins are developmentally regulated and function as members of multiple, heterogeneous complexes.
|Original language||English (US)|
|Number of pages||10|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Apr 17 1998|
Bibliographical noteFunding Information:
We thank Kazuki Sato for providing BMI1 peptide and Shinobu Fujita for information on modi®ed DAB procedure. H.W.B. was supported by the Medical Research Council of Canada, the National Cancer Institute of Canada, and the Natural Sciences and Engineering Research Council. K.S. was supported by Monbusho International Scienti®c Research Program (08044283) and Grant-in-Aid for Scienti®c Research (07457040) from The Ministry of Education, Science, Sports and Culture of Japan.