title: mab-7 encodes a novel transmembrane protein that orchestrates sensory ray morphogenesis in C. elegans.
abstract: The tapered sensory rays of the male Caenorhabditis elegans are important for successful male/hermaphrodite copulation. A group of ram (ray morphology abnormal) genes encoding modifying enzymes and transmembrane protein have been reported as key regulators controlling ray morphogenesis. Here we report the characterization of another component essential for this morphogenetic process encoded by mab-7. This gene is active in the hypodermis, structural cells, the body seam and several head neurons. It encodes a novel protein with a hydrophobic region at the N-terminus, an EGF-like motif, an ShKT motif and a long C-terminal tail. All these domains are shown to be critical to MAB-7 activity except the EGF-like domain, which appears to be regulatory and dispensable. MAB-7 is shown to be a type II membrane protein, tethered on the cell surface by the N-terminal transmembrane domain with the remainder of the protein exposed to the extracellular matrix. Since ectopic mab-7 expression in any ray cell or even in touch neurons of non-ray lineage can rescue the mutant phenotype, mab-7 is probably acting non-autonomously. It may facilitate intercellular communication among ray cells to augment normal ray morphogenesis.
authors.affiliation: Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors.forename: S W
authors.initials: SW
authors.lastname: Tsang
authors.forename: C Q
authors.initials: CQ
authors.lastname: Nguyen
authors.forename: D H
authors.initials: DH
authors.lastname: Hall
authors.forename: K L
authors.initials: KL
authors.lastname: Chow
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000825:Animal Structures / Q000196:embryology* / Q000648:ultrastructure; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000235:genetics / Q000648:ultrastructure; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019070:Cell Lineage; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D005816:Genetic Complementation Test; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009024:Morphogenesis; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D017434:Protein Structure, Tertiary; D013623:Tail / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; C525193:Mab-7 protein, C elegans; D008565:Membrane Proteins