A single, phosphate-repressible deoxyribonuclease, DNase A, secreted inAspergillus nidulans
- 27 Downloads
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 wordsAspergillus nidulans DNase A deoxyribonuclease secretion phosphate repression regulator genepalcA
Unable to display preview. Download preview PDF.
- Alberts, B., and Herrick, G. (1971). DNA-cellulose chromatography.Methods Enzymol. 21D198.Google Scholar
- 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