Biochemical Genetics

, Volume 27, Issue 3–4, pp 153–166 | Cite as

A single, phosphate-repressible deoxyribonuclease, DNase A, secreted inAspergillus nidulans

  • E. Käfer
  • A. Tittler
  • M. J. Fraser


High levels of nuclease activities were identified in filtrates ofAspergillus cultures after growth in low- but not in high-phosphate media. Deoxyribonuclease activities, characterized extensively by column chromatography, showed a coincident single peak for ss- and ds-DNase which was distinct from the peak for RNase. Both ss-DNase and ds-DNase are endonucleolytic and showed the highest activity in the presence of Ca2+ and Mn2+ (atpH 8.0). They also showed identical heat sensitivities suggesting that a single, phosphate-repressible DNase was secreted. This enzyme, therefore, corresponds to the well-characterized extracellular DNase A ofNeurospora. However, theAspergillus DNase A did not cross-react with antisera to secretedNeurospora nucleases and showed different chromatographic properties, and active peptides of different sizes were visualized on DNA activity gels. The increasing derepression ofAspergillus DNase A by decreasing phosphate levels was similar to that of secreted alkaline phosphatase and these increases were both abolished by the regulatory mutantpalcA.

Key words

Aspergillus nidulans DNase A deoxyribonuclease secretion phosphate repression regulator genepalcA 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Alberts, B., and Herrick, G. (1971). DNA-cellulose chromatography.Methods Enzymol. 21D198.Google Scholar
  2. Bowman, B. J. (1983). Vanadate uptake inNeurospora crassa occurs via phosphate transport system II.J. Bacteriol. 153286.PubMedGoogle Scholar
  3. Caddick, M. X., and Arst, H. N., Jr. (1986). Structural genes for phosphatases inAspergillus nidulans.Genet. Res. 4783.PubMedGoogle Scholar
  4. Caddick, M. X., Brownlee, A. G., and Arst, H. N., Jr. (1986). Phosphatase regulation inAspergillus nidulans: responses to nutritional starvation.Genet. Res. 4793.PubMedGoogle Scholar
  5. Campbell, A. M., and Winder, F. G. (1983). Properties of deoxyribonuclease 4 fromAspergillus nidulans.Biochim. Biophys. Acta 746125.PubMedGoogle Scholar
  6. Dorn, G. (1965). Genetic analysis of the phosphatases inAspergillus nidulans.Genet. Res. 613.CrossRefGoogle Scholar
  7. Fraser, M. J. (1979). Alkaline deoxyribonucleases released fromNeurospora crassa mycelia: two activities not released by mutants with multiple sensitivities to mutagens.Nucleic Acids Res. 6231.PubMedGoogle Scholar
  8. Fraser, M. J., and Cohen, H. (1983). Intracellular localization ofNeurospora crassa endoexonuclease and its putative precursor.J. Bacteriol. 154460.PubMedGoogle Scholar
  9. Fraser, M. J., Tjeerde, R., and Matsumoto, K. (1976). A second form of the single-strand specific endonuclease ofNeurospora crassa which is associated with a double-strand exonuclease.Can. J. Biochem. 54971.PubMedCrossRefGoogle Scholar
  10. Fraser, M. J., Chow, T. Y.-K., Cohen, H., and Koa, H. (1986). An immunological study ofNeurospora nucleases.Biochem. Cell Biol. 64106.PubMedCrossRefGoogle Scholar
  11. Hasunuma, K., and Ishikawa, T. (1972). Properties of two nuclease genes inNeurospora crassa.Genetics 70371.PubMedGoogle Scholar
  12. Käfer, E., and DeMoss, J. A. (1973). Formation of hybrid anthranilate synthetasein vitro from components ofAspergillus andNeurospora.Biochem. Genet. 9203.CrossRefPubMedGoogle Scholar
  13. Käfer, E., and Witchell, G. R. (1984). Effects ofNeurospora nuclease halo (nuh) mutants on secretion of two phosphate-repressible alkaline deoxyribonucleases.Biochem. Genet. 22403.CrossRefPubMedGoogle Scholar
  14. Lowry, O. H. (1957). Micromethods for the assay of enzymes.Methods Enzymol. 4366.CrossRefGoogle Scholar
  15. Lowry, O. H., Rosebrough, N. J., Farr, A. L., and Randall, R. J. (1951). Protein measurement with the Folin phenol reagent.J. Biol. Chem. 193265.PubMedGoogle Scholar
  16. Mann, B. J., Akins, R. A., Lambowitz, A. M., and Metzenberg, R. L. (1988). The structural gene for a phosphorus-repressible phosphate permease inNeurospora crassa can complement a mutation in positive regulatory genenuc-1.Mol. Cell. Biol. 81376.PubMedGoogle Scholar
  17. May, G. S., Gambino, J., Weatherbee, J. A., and Morris, N. R. (1985). Identification and functional analysis of beta-tubulin genes by site specific integrative transformation inAspergillus nidulans.J. Cell Biol. 101712.CrossRefPubMedGoogle Scholar
  18. Metzenberg, R. L. (1979). Implications of some genetic control mechanisms inNeurospora.Microbiol. Rev. 43361.PubMedGoogle Scholar
  19. Metzenberg, R. L., and Chia, W. (1979). Genetic control of phosphorus assimilation inNeurospora crassa: Dose-dependent dominance and recessiveness in constitutive mutants.Genetics 93625.PubMedGoogle Scholar
  20. Osmani, S. A., Engle, D. B., Doonan, J. H., and Morris, N. R. (1988). Spindle formation and chromatin condensation in cells blocked at interphase by mutation of a negative cell cycle control gene.Cell 52241.CrossRefPubMedGoogle Scholar
  21. Ramotar, D., Auchincloss, A. H., and Fraser, M. J. (1987). Nuclear endo-exonuclease ofNeurospora crassa. Evidence for a role in DNA repair.J. Biol. Chem. 262425.PubMedGoogle Scholar
  22. Scott, B. R., and Käfer, E. (1982).Aspergillus nidulans—An organism for detecting a range of genetic damage. In deSerres, F. J., and Hollaender, A. (eds.),Chemical Mutagens, Principles and Methods for Their Detection, Vol. 7 Plenum Press, New York, pp. 447–479.Google Scholar

Copyright information

© Plenum Publishing Corporation 1989

Authors and Affiliations

  • E. Käfer
    • 1
  • A. Tittler
    • 1
  • M. J. Fraser
    • 2
  1. 1.Department of BiologyMcGill UniversityMontrealCanada
  2. 2.Department of BiochemistryMcGill UniversityMontrealCanada

Personalised recommendations