title: Half-calmodulin is sufficient for cell proliferation. Expressions of N- and C-terminal halves of calmodulin in the yeast Saccharomyces cerevisiae.
abstract: Calmodulin (CaM) has been shown to be an essential component for progression of nuclear division in the yeast Saccharomyces cerevisiae (Ohya, Y., and Anraku, Y. (1989) Curr. Genet. 15, 113-120). To define the functional domain of the molecule required for cell proliferation, we constructed plasmids expressing a series of N- and C-terminal halves of the CaM under the control of the galactose-inducible GAL1 promoter. These plasmids were introduced into a cmd1-disrupted yeast haploid strain, and the growth properties of the cells depending on the half-CaMs were examined. Plasmids expressing the N-terminal half (Ser1-Leu76) and the C-terminal half (Leu85-Cys147), which each maintain two complete EF-hand structures, complemented the growth defect of the cmd1 null mutation, whereas those expressing shorter regions of C- and N-terminal CaM did not. The half-CaMs that complemented the cmd1 null mutation were found to be approximately 6-fold overexpressed relative to expression of native CaM by the wild-type CMD1 gene. The levels of expression of the half CaMs with the true CMD1 promoter were not sufficient for complementation. These results demonstrate that half-CaMs (either the N- or the C-terminal) are capable of supporting growth of yeast cells when they are suitably overproduced. Cells depending solely on half-CaMs all showed a temperature-sensitive growth phenotype, suggesting that half-CaMs cannot carry out all the cellular functions of the complete CaM molecule.
authors.affiliation: Department of Biology, Faculty of Science, University of Tokyo, Japan.
authors.forename: G H
authors.initials: GH
authors.lastname: Sun
authors.forename: Y
authors.initials: Y
authors.lastname: Ohya
authors.forename: Y
authors.initials: Y
authors.lastname: Anraku
mesh_terms: D001483:Base Sequence; D002147:Calmodulin / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D002455:Cell Division; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D004171:Diploidy; D005690:Galactose / Q000378:metabolism; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D005947:Glucose / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D015345:Oligonucleotide Probes; D010641:Phenotype; D010957:Plasmids; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D013172:Spores, Fungal / Q000502:physiology
chemical_list: D002147:Calmodulin; D015345:Oligonucleotide Probes; D005947:Glucose; D005690:Galactose