title: Nidogen is nonessential and not required for normal type IV collagen localization in Caenorhabditis elegans.
abstract: Nidogen (entactin) can form a ternary complex with type IV collagen and laminin and is thought to play a critical role in basement membrane assembly. We show that the Caenorhabditis elegans nidogen homologue nid-1 generates three isoforms that differ in numbers of rod domain endothelial growth factor repeats and are differentially expressed during development. NID-1 appears at the start of embryonic morphogenesis associated with muscle cells and subsequently accumulates on pharyngeal, intestinal, and gonad primordia. In larvae and adults NID-1 is detected in most basement membranes but accumulates most strongly around the nerve ring and developing gonad. NID-1 is concentrated under dense bodies, at the edges of muscle quadrants, and on the sublateral nerves that run under muscles. Two deletions in nid-1 were isolated: cg119 is a molecular null, whereas cg118 produces truncated NID-1 missing the G2 collagen IV binding domain. Neither deletion causes overt abnormal phenotypes, except for mildly reduced fecundity. Truncated cg118 NID-1 shows wild-type localization, demonstrating that the G2 domain is not necessary for nidogen assembly. Both nid-1 mutants assemble type IV collagen in a completely wild-type pattern, demonstrating that nidogen is not essential for type IV collagen assembly into basement membranes.
authors.affiliation: Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Kang
authors.forename: J M
authors.initials: JM
authors.lastname: Kramer
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D005298:Fertility / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D024510:Muscle Development; D009132:Muscles / Q000378:metabolism; D009154:Mutation
chemical_list: D008562:Membrane Glycoproteins; C029967:nidogen; D003094:Collagen