title: Recruitment of Drosophila Polycomb-group proteins by Polycomblike, a component of a novel protein complex in larvae.
abstract: Polycomb-group (PcG) proteins are highly conserved epigenetic transcriptional repressors that play central roles in numerous examples of developmental gene regulation. Four PcG repressor complexes have been purified from Drosophila embryos: PRC1, PRC2, Pcl-PRC2 and PhoRC. Previous studies described a hierarchical recruitment pathway of PcG proteins at the bxd Polycomb Response Element (PRE) of the Ultrabithorax (Ubx) gene in larval wing imaginal discs. The DNA-binding proteins Pho and/or Phol are required for target site binding by PRC2, which in turn is required for chromosome binding by PRC1. Here, we identify a novel larval complex that contains the PcG protein Polycomblike (Pcl) that is distinct from PRC1 and PRC2 and which is also dependent on Pho and/or Phol for binding to the bxd PRE in wing imaginal discs. RNAi-mediated depletion of Pcl in larvae disrupts chromosome binding by E(z), a core component of PRC2, but Pcl does not require E(z) for chromosome binding. These results place the Pcl complex (PCLC) downstream of Pho and/or Phol and upstream of PRC2 and PRC1 in the recruitment hierarchy.
authors.affiliation: Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA.
authors.forename: Urmi
authors.initials: U
authors.lastname: Savla
authors.forename: Judith
authors.initials: J
authors.lastname: Benes
authors.forename: Junyu
authors.initials: J
authors.lastname: Zhang
authors.forename: Richard S
authors.initials: RS
authors.lastname: Jones
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000502:physiology*; D002843:Chromatin / Q000302:isolation & purification; D002850:Chromatography, Gel; D002875:Chromosomes / Q000502:physiology; D004330:Drosophila / Q000235:genetics / Q000254:growth & development*; D029721:Drosophila Proteins / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D016678:Genome; D007814:Larva; D063150:Polycomb Repressive Complex 1; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D014921:Wings, Animal / Q000196:embryology / Q000254:growth & development
chemical_list: D002843:Chromatin; D029721:Drosophila Proteins; C066770:Pc protein, Drosophila; C095065:Pcl protein, Drosophila; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1