title: Global regulation of Hox gene expression in C. elegans by a SAM domain protein.
abstract: Polycomb group (PcG)-mediated repression of C. elegans Hox genes has not been demonstrated, and genes homologous to components of one of the PcG complexes (PRC1) have not been identified in the C. elegans genome. We find that a mechanism of general Hox gene repression exists in C. elegans, carried out in part by SOP-2, a protein related to, but not orthologous with, any PcG protein. sop-2 mutations lead to widespread ectopic expression of Hox genes and homeotic transformations. SOP-2 contains a SAM domain, a self-associating protein domain found in other repressors, including a core component of PRC1 and ETS transcription factors. Phylogenetic analysis indicates that this domain is more closely related to those of the ETS family than to those of PcG proteins. The results suggest that global repression of Hox genes has been taken over by a different branch of the SAM domain family during the evolution of nematodes.
authors.affiliation: Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA. zhangh@helix.mgh.harvard.edu
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Ricardo B R
authors.initials: RB
authors.lastname: Azevedo
authors.forename: Robyn
authors.initials: R
authors.lastname: Lints
authors.forename: Christina
authors.initials: C
authors.lastname: Doyle
authors.forename: Yingqi
authors.initials: Y
authors.lastname: Teng
authors.forename: Daniel
authors.initials: D
authors.lastname: Haber
authors.forename: Scott W
authors.initials: SW
authors.lastname: Emmons
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D005801:Genes, Homeobox; D007814:Larva; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D020161:Physical Chromosome Mapping; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D012097:Repressor Proteins / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D029742:Caenorhabditis elegans Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C475806:Sop-2 protein, C elegans