Skip to main content
PMC home page
Genetics logoLink to Genetics
. 1994 Jul;137(3):723–730. doi: 10.1093/genetics/137.3.723

Superoxide Dismutase (Sod-1) Null Mutants of Neurospora Crassa: Oxidative Stress Sensitivity, Spontaneous Mutation Rate and Response to Mutagens

P Chary 1, D Dillon 1, A L Schroeder 1, D O Natvig 1
PMCID: PMC1206032  PMID: 8088518

Abstract

Enzymatic superoxide-dismutase activity is believed to be important in defense against the toxic effects of superoxide. Although superoxide dismutases are among the best studied proteins, numerous questions remain concerning the specific biological roles of the various superoxide-dismutase types. In part, this is because the proposed damaging effects of superoxide are manifold, ranging from inactivation of certain metabolic enzymes to DNA damage. Studies with superoxide-deficient mutants have proven valuable, but surprisingly few such studies have been reported. We have constructed and characterized Neurospora crassa mutants that are null for sod-1, the gene that encodes copper-zinc superoxide dismutase. Mutant strains are sensitive to paraquat and elevated oxygen concentrations, and they exhibit an increased spontaneous mutation rate. They appear to have near wild-type sensitivities to near- and far-UV, heat shock and γ-irradiation. Unlike the equivalent Saccharomyces cerevisiae mutant and the sodA sodB double mutant of Escherichia coli, they do not exhibit aerobic auxotrophy. These results are discussed in the context of an attempt to identify consensus phenotypes among superoxide dismutase-deficient mutants. N. crassa sod-1 null mutant strains were also employed in genetic and subcellular fractionation studies. Results support the hypothesis that a single gene (sod-1), located between Fsr-12 and leu-3 on linkage group I, is responsible for most or all CuZn superoxide dismutase activity in this organism.

Full Text

The Full Text of this article is available as a PDF (4.2 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Beauchamp C., Fridovich I. Superoxide dismutase: improved assays and an assay applicable to acrylamide gels. Anal Biochem. 1971 Nov;44(1):276–287. doi: 10.1016/0003-2697(71)90370-8. [DOI] [PubMed] [Google Scholar]
  2. Biliński T., Krawiec Z., Liczmański A., Litwińska J. Is hydroxyl radical generated by the Fenton reaction in vivo? Biochem Biophys Res Commun. 1985 Jul 31;130(2):533–539. doi: 10.1016/0006-291x(85)90449-8. [DOI] [PubMed] [Google Scholar]
  3. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1006/abio.1976.9999. [DOI] [PubMed] [Google Scholar]
  4. Carlioz A., Touati D. Isolation of superoxide dismutase mutants in Escherichia coli: is superoxide dismutase necessary for aerobic life? EMBO J. 1986 Mar;5(3):623–630. doi: 10.1002/j.1460-2075.1986.tb04256.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Chang E. C., Kosman D. J. O2-dependent methionine auxotrophy in Cu,Zn superoxide dismutase-deficient mutants of Saccharomyces cerevisiae. J Bacteriol. 1990 Apr;172(4):1840–1845. doi: 10.1128/jb.172.4.1840-1845.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Chary P., Hallewell R. A., Natvig D. O. Structure, exon pattern, and chromosome mapping of the gene for cytosolic copper-zinc superoxide dismutase (sod-1) from Neurospora crassa. J Biol Chem. 1990 Nov 5;265(31):18961–18967. [PubMed] [Google Scholar]
  7. Cramer C. L., Ristow J. L., Paulus T. J., Davis R. H. Methods for mycelial breakage and isolation of mitochondria and vacuoles of Neurospora. Anal Biochem. 1983 Feb 1;128(2):384–392. doi: 10.1016/0003-2697(83)90390-1. [DOI] [PubMed] [Google Scholar]
  8. Drake J. W. A constant rate of spontaneous mutation in DNA-based microbes. Proc Natl Acad Sci U S A. 1991 Aug 15;88(16):7160–7164. doi: 10.1073/pnas.88.16.7160. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Farr S. B., D'Ari R., Touati D. Oxygen-dependent mutagenesis in Escherichia coli lacking superoxide dismutase. Proc Natl Acad Sci U S A. 1986 Nov;83(21):8268–8272. doi: 10.1073/pnas.83.21.8268. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Farr S. B., Kogoma T. Oxidative stress responses in Escherichia coli and Salmonella typhimurium. Microbiol Rev. 1991 Dec;55(4):561–585. doi: 10.1128/mr.55.4.561-585.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Gralla E. B., Kosman D. J. Molecular genetics of superoxide dismutases in yeasts and related fungi. Adv Genet. 1992;30:251–319. doi: 10.1016/s0065-2660(08)60322-3. [DOI] [PubMed] [Google Scholar]
  12. Hartman P. S., Eisenstark A. Synergistic killing of Escherichia coli by near-UV radiation and hydrogen peroxide: distinction between recA-repairable and recA-nonrepairable damage. J Bacteriol. 1978 Feb;133(2):769–774. doi: 10.1128/jb.133.2.769-774.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Hassan H. M., Fridovich I. Regulation of the synthesis of superoxide dismutase in Escherichia coli. Induction by methyl viologen. J Biol Chem. 1977 Nov 10;252(21):7667–7672. [PubMed] [Google Scholar]
  14. Henry L. E., Cammack R., Schwitzguebel J. P., Palmer J. M., Hall D. O. Intracellular localization, isolation and characterization of two distinct varieties of superoxide dismutase from Neurospora crassa. Biochem J. 1980 May 1;187(2):321–328. doi: 10.1042/bj1870321. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Hughes K., Case M. E., Geever R., Vapnek D., Giles N. H. Chimeric plasmid that replicates autonomously in both Escherichia coli and Neurospora crassa. Proc Natl Acad Sci U S A. 1983 Feb;80(4):1053–1057. doi: 10.1073/pnas.80.4.1053. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Kolmark H. G. Protection by endogenous anoxia against the mutagenic and lethal effects of x-rays in Neurospora crassa. Mutat Res. 1965 Jun;2(3):222–228. doi: 10.1016/0027-5107(65)90032-1. [DOI] [PubMed] [Google Scholar]
  17. Liu X. F., Elashvili I., Gralla E. B., Valentine J. S., Lapinskas P., Culotta V. C. Yeast lacking superoxide dismutase. Isolation of genetic suppressors. J Biol Chem. 1992 Sep 15;267(26):18298–18302. [PubMed] [Google Scholar]
  18. Phillips J. P., Campbell S. D., Michaud D., Charbonneau M., Hilliker A. J. Null mutation of copper/zinc superoxide dismutase in Drosophila confers hypersensitivity to paraquat and reduced longevity. Proc Natl Acad Sci U S A. 1989 Apr;86(8):2761–2765. doi: 10.1073/pnas.86.8.2761. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Plesofsky-Vig N., Brambl R. Heat shock response of Neurospora crassa: protein synthesis and induced thermotolerance. J Bacteriol. 1985 Jun;162(3):1083–1091. doi: 10.1128/jb.162.3.1083-1091.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Rosen D. R., Siddique T., Patterson D., Figlewicz D. A., Sapp P., Hentati A., Donaldson D., Goto J., O'Regan J. P., Deng H. X. Mutations in Cu/Zn superoxide dismutase gene are associated with familial amyotrophic lateral sclerosis. Nature. 1993 Mar 4;362(6415):59–62. doi: 10.1038/362059a0. [DOI] [PubMed] [Google Scholar]
  21. Scott M. D., Meshnick S. R., Eaton J. W. Superoxide dismutase amplifies organismal sensitivity to ionizing radiation. J Biol Chem. 1989 Feb 15;264(5):2498–2501. [PubMed] [Google Scholar]
  22. Selker E. U., Cambareri E. B., Jensen B. C., Haack K. R. Rearrangement of duplicated DNA in specialized cells of Neurospora. Cell. 1987 Dec 4;51(5):741–752. doi: 10.1016/0092-8674(87)90097-3. [DOI] [PubMed] [Google Scholar]
  23. Stadler D., Macleod H., Dillon D. Spontaneous mutation at the mtr locus of Neurospora: the spectrum of mutant types. Genetics. 1991 Sep;129(1):39–45. doi: 10.1093/genetics/129.1.39. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Totter J. R. Spontaneous cancer and its possible relationship to oxygen metabolism. Proc Natl Acad Sci U S A. 1980 Apr;77(4):1763–1767. doi: 10.1073/pnas.77.4.1763. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Vollmer S. J., Yanofsky C. Efficient cloning of genes of Neurospora crassa. Proc Natl Acad Sci U S A. 1986 Jul;83(13):4869–4873. doi: 10.1073/pnas.83.13.4869. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Genetics are provided here courtesy of Oxford University Press

RESOURCES