title: Multiple effects of mutation on expression of alternative cell surface protein genes in Tetrahymena thermophila.
abstract: Genes at the SerH locus of the ciliated protist Tetrahymena thermophila specify the major (H) surface protein on cells grown at 20-36 degrees. Alternative proteins L, T, S and I are expressed under different conditions of temperature and culture media. Mutants unable to express SerH genes were examined for expression of these proteins, also called immobilization or i-antigens, at both H and non-H conditions. In all instances, one or more i-antigens were expressed in the absence of H, and, in most instances, expression of i-antigens under non-H conditions was also affected. Examples of the latter include both the continued expression of H-replacement antigens and the inability to express certain other i-antigens. Such multiple effects were observed in mutants with trans-acting (rseA, rseB, rseC, RseD) and cis-acting (H1-1 and H1-2) mutations, but not in mutants in which SerH is affected developmentally (B2092, B2101, B2103, B2107). These interactions suggest that the wild-type genes identified by mutation exert both positive and negative effects in the regulation of i-antigen gene expression.
authors.affiliation: Department of Biology, Cleveland State University, Ohio 44115.
authors.forename: D L
authors.initials: DL
authors.lastname: Smith
authors.forename: F P
authors.initials: FP
authors.lastname: Doerder
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics*; D000954:Antigens, Surface / Q000235:genetics*; D015153:Blotting, Western; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000235:genetics*; D005796:Genes / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D015800:Protozoan Proteins / Q000235:genetics*; D013696:Temperature; D016808:Tetrahymena thermophila / Q000235:genetics* / Q000276:immunology
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D015800:Protozoan Proteins; C043323:immobilization antigens