Gene assignment, expression, and homology of human tropomodulin.
Tropomodulin is a newly characterized pointed end capping protein for actin filaments. It binds specifically to the N terminus of tropomyosin and blocks the elongation and depolymerization of tropomyosin-coated actin filaments. A 1.9-kb human tropomodulin cDNA clone was used to map its gene by fluorescence in situ hybridization. The tropomodulin gene was assigned to human chromosome 9q22.2-q22.3, a region that is also known to contain several other genes and disease loci and is proximal to the loci for gelsolin and alpha-fodrin. The gene for tropomodulin is expressed in major human tissues at different levels in the following order: heart and skeletal muscle much greater than that in brain, lung, and pancreas, which is greater than that in placenta, liver, and kidney. Human tropomodulin and a 64-kDa autoantigen in Graves disease (1D) are related: tropomodulin has 42 and 41% identity with the Graves protein in the N-terminal (69 residue) and C-terminal (194 residue) regions, respectively. The insertion of several homologous repeats in the midsection of the Graves protein, together with the extension of a proline-rich C terminus, accounts for the differences in length between the Graves protein (572 residues) and tropomodulin (359 residues). The significant sequence identity indicates that these two genes are evolved from a common ancestral gene.
Sung
L A
LA
Department of Bioengineering and Center for Molecular Genetics, University of California at San Diego, La Jolla, California, 92093-0412, USA.
Fan
Y
Y
Lin
C C
CC
D000595:Amino Acid Sequence; D001324:Autoantigens / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics*; D002874:Chromosome Mapping; D002899:Chromosomes, Human, Pair 9; D006111:Graves Disease / Q000276:immunology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D051348:Tropomodulin
D001324:Autoantigens; D002352:Carrier Proteins; D008840:Microfilament Proteins; C495829:TMOD1 protein, human; D051348:Tropomodulin