title: The C. elegans HP1 homologue HPL-2 and the LIN-13 zinc finger protein form a complex implicated in vulval development.
abstract: HP1 proteins are essential components of heterochromatin and contribute to the transcriptional repression of euchromatic genes via the recruitment to specific promoters by corepressor proteins including TIF1 and Rb. The Caenorhabditis elegans HP1 homologue HPL-2 acts in the "synMuv" (synthetic multivulval) pathway, which defines redundant negative regulators of a Ras signaling cascade required for vulval induction. Several synMuv genes encode for chromatin-associated proteins involved in transcriptional regulation, including Rb and components of the Mi-2/NuRD and TIP60/NuA4 chromatin remodeling complexes. Here, we show that HPL-2 physically interacts in vitro and in vivo with the multiple zinc finger protein LIN-13, another member of the synMuv pathway. A variant of the conserved PXVXL motif found in many HP1-interacting proteins mediates LIN-13 binding to the CSD of HPL-2. We further show by in vivo localization studies that LIN-13 is required for HPL-2 recruitment in nuclear foci. Our data suggest that the LIN-13/HPL-2 complex may physically link a subset of the Rb related synMuv proteins to chromatin.
authors.affiliation: Laboratoire de Biologie Moleculaire de la Cellule, Ecole Normale Supérieure de Lyon, 69007 Lyon, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Coustham
authors.forename: Cécile
authors.initials: C
authors.lastname: Bedet
authors.forename: Karine
authors.initials: K
authors.lastname: Monier
authors.forename: Sonia
authors.initials: S
authors.lastname: Schott
authors.forename: Marianthi
authors.initials: M
authors.lastname: Karali
authors.forename: Francesca
authors.initials: F
authors.lastname: Palladino
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000502:physiology*; D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology*; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000502:physiology*; D017124:Conserved Sequence; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D014844:Vulva / Q000196:embryology*
chemical_list: D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D002868:Chromosomal Proteins, Non-Histone; C514742:HPL-2 protein, C elegans; C514743:LIN-13 protein, C elegans; D000090266:Chromobox Protein Homolog 5