title: The mab-21 gene of Caenorhabditis elegans encodes a novel protein required for choice of alternate cell fates.
abstract: The gene mab-21, which encodes a novel protein of 386 amino acids, is required for the choice of alternate cell fates by several cells in the C. elegans male tail. Three cells descended from the ray 6 precursor cell adopt fates of anterior homologs, and a fourth, lineally unrelated hypodermal cell is transformed into a neuroblast. The affected cells lie together in the lateral tail epidermis, suggesting that mab-21 acts as part of a short-range pattern-formation mechanism. Each of the changes in cell fate brought about by mab-21 mutants can be interpreted as a posterior-to-anterior homeotic transformation. mab-21 mutant males and hermaphrodites have additional pleiotropic phenotypes affecting movement, body shape and fecundity, indicating that mab-21 has functions outside the tail region of males. We show that the three known alleles of mab-21 are hypomorphs of a new gene. Mosaic analysis revealed that mab-21 acts cell autonomously to specify the properties of the sensory ray, but non-autonomously in the hypodermal versus neuroblast cell fate choice. Presence of cell signalling in the choice of the neuroblast fate was confirmed by cell ablation experiments. Mutations in mab-21 were shown previously to be genetic modifiers of the effects of HOM-C/Hox gene mutations on ray identity specification. The results presented here support the conclusion that mab-21 acts as part of a mechanism required for correct cell fate choice, possibly involving the function of HOM-C/Hox genes in several body regions.
authors.affiliation: Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Chow
authors.forename: D H
authors.initials: DH
authors.lastname: Hall
authors.forename: S W
authors.initials: SW
authors.lastname: Emmons
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics; D003001:Cloning, Molecular; D019084:Fluorescent Antibody Technique, Indirect; D017238:Genes, Helminth; D005801:Genes, Homeobox; D015801:Helminth Proteins / Q000235:genetics*; D008297:Male; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics; D009030:Mosaicism; D009420:Nervous System / Q000196:embryology*; D015398:Signal Transduction / Q000235:genetics; D013623:Tail / Q000196:embryology* / Q000648:ultrastructure
chemical_list: D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; C098124:Mab-21 protein, C elegans