A novel superoxide dismutase gene encoding membrane-bound and extracellular isoforms by alternative splicing in Caenorhabditis elegans.
We have identified a novel Cu/Zn superoxide dismutase gene (termed SOD-4) in Caenorhabditis elegans. Characterization of its complementary DNA revealed that the gene encodes two isoforms by alternative splicing, SOD4-1 and SOD4-2 which differ in their C-terminal exons. Their predicted amino acid sequences include a consensus signal peptide at their N-termini and are homologous to the extracellular-types of Cu/Zn superoxide dismutase in mammals. In addition, SOD4-2 possesses a putative transmembrane domain at the C-terminal region. When transiently expressed in Chinese hamster ovary cells, both types were found in the membranes and SOD4-1 also in the culture fluid. It is, therefore, indicated that SOD4-1 is an extracellular form and SOD4-2 a membrane-bound form, the latter representing a novel type of SOD. In C. elegans, SOD4-2 mRNA was found to be preferentially expressed in eggs.
Fujii
M
M
Department of Biochemistry, Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan.
Ishii
N
N
Joguchi
A
A
Yasuda
K
K
Ayusawa
D
D
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D017173:Caenorhabditis elegans / Q000201:enzymology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002462:Cell Membrane / Q000201:enzymology; D006224:Cricetinae; D007527:Isoenzymes / Q000235:genetics*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013482:Superoxide Dismutase / Q000235:genetics*
D029742:Caenorhabditis elegans Proteins; D007527:Isoenzymes; C113846:SOD-4 protein, C elegans; D013482:Superoxide Dismutase