title: Hox gene expression in a single Caenorhabditis elegans cell is regulated by a caudal homolog and intercellular signals that inhibit wnt signaling.
abstract: In Caenorhabditis elegans males, a row of epidermal precursor cells called seam cells generates a pattern of cuticular alae in anterior body regions and neural sensilla called rays in the posterior. The Hox gene mab-5 is required for two posterior seam cells, V5 and V6, to generate rays. In mab-5 mutant males, V5 and V6 do not generate sensory ray lineages but instead generate lineages that lead to alae. Here we show that two independent regulatory pathways can activate mab-5 expression in the V cells. First, the caudal homolog pal-1 turns on mab-5 in V6 during embryogenesis. Second, a Wnt signaling pathway is capable of activating mab-5 in the V cells during postembryonic development; however, during normal development Wnt signaling is inhibited by signals from neighboring V cells. The inhibition of this Wnt signaling pathway by lateral signals between the V cells limits the number of rays in the animal and also determines the position of the boundary between alae and rays.
authors.affiliation: Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143-0554, USA. hunter@biosun.harvard.edu
authors.forename: C P
authors.initials: CP
authors.lastname: Hunter
authors.forename: J M
authors.initials: JM
authors.lastname: Harris
authors.forename: J N
authors.initials: JN
authors.lastname: Maloof
authors.forename: C
authors.initials: C
authors.lastname: Kenyon
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D047108:Embryonic Development; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D005801:Genes, Homeobox / Q000235:genetics*; D006023:Glycoproteins / Q000235:genetics; D015801:Helminth Proteins / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics; D007763:Lac Operon / Q000235:genetics; D008297:Male; D009154:Mutation / Q000235:genetics; D010375:Pedigree; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics; D051153:Wnt Proteins; D029961:Zebrafish Proteins
chemical_list: D029742:Caenorhabditis elegans Proteins; C117259:Egl-20 protein, C elegans; D006023:Glycoproteins; D015801:Helminth Proteins; D018398:Homeodomain Proteins; C081538:Mab-5 protein, C elegans; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D051153:Wnt Proteins; D029961:Zebrafish Proteins; C068665:pal-1 protein, C elegans