RAE28, BMI1, and M33 are members of heterogeneous multimeric mammalian Polycomb group complexes

Biochem Biophys Res Commun. 1998 Apr 17;245(2):356-65. doi: 10.1006/bbrc.1998.8438.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carrier Proteins*
  • Cells, Cultured
  • Embryo, Mammalian / metabolism
  • Gene Expression Regulation, Developmental / genetics
  • Homeodomain Proteins / chemistry*
  • Immunohistochemistry
  • Mice
  • Nuclear Proteins / chemistry
  • Polycomb Repressive Complex 1
  • Polycomb-Group Proteins
  • Precipitin Tests
  • Protein Conformation
  • Repressor Proteins / chemistry*
  • Transcription Factors / chemistry


  • Carrier Proteins
  • Cbx2 protein, mouse
  • Homeodomain Proteins
  • Nuclear Proteins
  • Phc1 protein, mouse
  • Polycomb-Group Proteins
  • Repressor Proteins
  • Transcription Factors
  • Polycomb Repressive Complex 1