title: Tissue expression of four troponin I genes and their molecular interactions with two troponin C isoforms in Caenorhabditis elegans.
abstract: Gene duplication is a major genetic event that can produce multiple protein isoforms. Comparative sequence and functional analysis of related gene products can provide insights into protein family evolution. To characterize the Caenorhabditis elegans troponin I family, we analyzed gene structures, tissue expression patterns and RNAi phenotypes of four troponin I isoforms. Tissue expression patterns were determined using lacZ/gfp/rfp reporter gene assays. The tni-1, tni-2/unc-27 and tni-3 genes, each encoding a troponin I isoform, are uniquely expressed in body wall, vulval and anal muscles but at different levels; tni-4 was expressed solely in the pharynx. Expressing tni-1 and -2 gene RNAi caused motility defects similar to unc-27 (e155) mutant, a tni-2 null allele. The tni-3 RNAi expression produced egg laying defects while the tni-4 RNAi caused arrest at gastrulation. Overlay analyses were used to assay interactions between the troponin I and two troponin C isoforms. The three body wall troponin I isoforms interacted with body wall and pharyngeal troponin C isoforms; TNI-4 interacted only with pharyngeal troponin C. Our results suggest the body wall genes have evolved following duplication of the pharynx gene and provide important data about gene duplication and functional differentiation of nematode troponin I isoforms.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
authors.forename: Razia
authors.initials: R
authors.lastname: Ruksana
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kuroda
authors.forename: Hiromi
authors.initials: H
authors.lastname: Terami
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Bando
authors.forename: Shun
authors.initials: S
authors.lastname: Kitaoka
authors.forename: Tomohide
authors.initials: T
authors.lastname: Takaya
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Sakube
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kagawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D020033:Protein Isoforms; D034622:RNA Interference; D017385:Sequence Homology; D019209:Troponin C / Q000235:genetics / Q000378:metabolism*; D019210:Troponin I / Q000235:genetics* / Q000378:metabolism
chemical_list: D020033:Protein Isoforms; D019209:Troponin C; D019210:Troponin I