A 1-megadalton ESC/E(Z) complex from Drosophila that contains polycomblike and RPD3.
Polycomb group (PcG) proteins are required to maintain stable repression of the homeotic genes and others throughout development. The PcG proteins ESC and E(Z) are present in a prominent 600-kDa complex as well as in a number of higher-molecular-mass complexes. Here we identify and characterize a 1-MDa ESC/E(Z) complex that is distinguished from the 600-kDa complex by the presence of the PcG protein Polycomblike (PCL) and the histone deacetylase RPD3. In addition, the 1-MDa complex shares with the 600-kDa complex the histone binding protein p55 and the PcG protein SU(Z)12. Coimmunoprecipitation assays performed on embryo extracts and gel filtration column fractions indicate that, during embryogenesis E(Z), SU(Z)12, and p55 are present in all ESC complexes, while PCL and RPD3 are associated with ESC, E(Z), SU(Z)12, and p55 only in the 1-MDa complex. Glutathione transferase pulldown assays demonstrate that RPD3 binds directly to PCL via the conserved PHD fingers of PCL and the N terminus of RPD3. PCL and E(Z) colocalize virtually completely on polytene chromosomes and are associated with a subset of RPD3 sites. As previously shown for E(Z) and RPD3, PCL and SU(Z)12 are also recruited to the insertion site of a minimal Ubx Polycomb response element transgene in vivo. Consistent with these biochemical and cytological results, Rpd3 mutations enhance the phenotypes of Pcl mutants, further indicating that RPD3 is required for PcG silencing and possibly for PCL function. These results suggest that there may be multiple ESC/E(Z) complexes with distinct functions in vivo.
Tie
Feng
F
Department of Genetics, Case Western Reserve University, Cleveland, Ohio 44106, USA.
Prasad-Sinha
Jayashree
J
Birve
Anna
A
Rasmuson-Lestander
Asa
A
Harte
Peter J
PJ
D000818:Animals; D030801:Animals, Genetically Modified; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004330:Drosophila / Q000196:embryology / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D005260:Female; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D011495:Histone-Lysine N-Methyltransferase; D018398:Homeodomain Proteins; D046911:Macromolecular Substances; D008297:Male; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D063150:Polycomb Repressive Complex 1; D063151:Polycomb Repressive Complex 2; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; C066770:Pc protein, Drosophila; C095065:Pcl protein, Drosophila; D012097:Repressor Proteins; C543390:Su(z)12 protein, Drosophila; D014157:Transcription Factors; C066177:Ubx protein, Drosophila; C083329:E(z) protein, Drosophila; D011495:Histone-Lysine N-Methyltransferase; D063151:Polycomb Repressive Complex 2; C543389:esc protein, Drosophila; D063150:Polycomb Repressive Complex 1; C512966:HDAC1 protein, Drosophila; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases