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Complementation relationships of Neurospora am mutants in relation to their formation of abnormal varieties of glutamate dehydrogenase

Published online by Cambridge University Press:  14 April 2009

J. R. S. Fincham  and
D. R. Stadler
J. R. S. Fincham
Affiliation:
John Innes Institute, Bayfordbury, Hertford, Herts.
D. R. Stadler
Affiliation:
John Innes Institute, Bayfordbury, Hertford, Herts.
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Six new am mutants of Neurospora, am14–am19, with defective formation of NADP-linked glutamate dehydrogenase, were isolated following treatment of conidia with nitrous acid. This brings the number of genetically distinct and viable am mutants to sixteen. Heterocaryon-compatible isolates of each of the new mutants were tested for complementation with each of the mutants previously known. A number of new complementary combinations were found which add to the complexity of the complementation map which, however, remains linear.

The mutants which show complementation are am1, am2, am3, am7, am14 and am19. It has proved possible to isolate an altered form of glutamate dehydrogenase from each of these except am14, which appears to produce no protein fractionating like the normal enzyme. Among the non-complementing mutants, am4 produces an easily-isolated inactive form of glutamate dehydrogenase. These results agree with the immunochemical findings of Roberts & Pateman (1964).

Of the mutationally altered forms of the enzyme, the am1, am2, am3 and am7varieties are electrophoretically identical or closely similar to the normal protein, while the am4 and am19 varieties move faster towards the anode at pH 8·5, am19being the faster of the two. The am19 protein, like the am2 and am3 proteins previously reported on, can be activated to give some enzyme activity, but the activity obtained is much lower for this mutant than for am2 or am3.

All the complementary pairs of mutants, including those involving am19, form active enzyme varieties which have very close to normal electrophoretic properties. In several cases the complementation enzyme is less stable to heat than the wild-type enzyme.

Type
Research Article
Information
Genetics Research , Volume 6 , Issue 1 , February 1965 , pp. 121 - 129
Copyright
Copyright © Cambridge University Press 1965

References

REFERENCES

De Serres, F. J. (1962). Heterocaryon-incompatibility factor interaction in tests between Neurospora mutants. Science, 138, 1342–1343.CrossRefGoogle ScholarPubMed
Fincham, J. R. S. (1950). Mutants of Neurospora deficient in animating ability. J. biol. Chem. 182, 61–73.Google Scholar
Fincham, J. R. S. (1958). On the nature of the glutamic dehydrogenase produced by interallelic complementation at the am locus of Neurospora crassa. J. gen. Microbiol. 21, 600–611.Google Scholar
Fincham, J. R. S. (1959). The role of chromosomal loci in enzyme formation. Proc. X Int. Congr. Genet. I, 355–363. Toronto: University Press.Google Scholar
Fincham, J. R. S. (1962). Genetically determined multiple forms of glutamic dehydrogenase in Neurospora crassa. J. Mol. Biol. 4, 257–274.Google Scholar
Fincham, J. R. S. & Coddington, A. (1963 b). The mechanism of complementation between am mutants of Neurospora crassa. Cold Spr. Harb. Symp. quant. Biol. 28, 517–527.Google Scholar
Fincham, J. R. S. & Coddington, A. (1963 a). Complementation at the am locus of Neurospora crassa: a reaction between different mutant forms of glutamate dehydrogenase. J. Mol. Biol. 6, 361–373.CrossRefGoogle Scholar
Garen, A. & Garen, S. (1963). Complementation in vivo between structural mutants of alkaline phosphatase from E. coli. J. Mol. Biol. 7, 13–22.CrossRefGoogle ScholarPubMed
Kaplan, S., Ensign, S., Bonner, D. M. & Mills, S. E. (1964). Gene products of CRM-mutants at the td locus. Proc. nat. Acad. Sci., Wash., 51, 372–378.Google Scholar
Lowry, O. H., Rosebrough, N. J., Farr, N. J. & Randall, R. J. (1951). Protein measurement with the Folin phenol reagent. J. biol. Chem. 193, 265.Google Scholar
Markert, C. L. & Møller, F. (1959). Multiple forms of enzymes: tissue ontogenetic, and species specific patterns. Proc. nat. Acad. Sci., Wash., 45, 753.CrossRefGoogle ScholarPubMed
Ornstein, L. & Davis, B. J. (1961). Disc Electrophoresis. Preprint distributed by Kodak Ltd., Kirby, Liverpool, U.K.Google Scholar
Roberts, D. B. & Pateman, J. A. (1964). Immunological studies of animation deficient strains of Neurospora crassa. J. gen. Microbiol. 34, 295–306.Google Scholar
Siddiqi, O. (1962). Mutagenic action of nitrous acid on Aspergillus nidulans. Genet. Res. 3, 303.Google Scholar
Schlesinger, M. & Levinthal, C. (1963). Hybrid protein formation of E. coli alkaline phosphatase leading to in vitro complementation. J. Mol. Biol. 1, 1–12.Google Scholar
Sundaram, T. K. & Fincham, J. R. S.A mutant enzyme in Neurospora crassa interconvertible between electrophoretically distinct active and inactive forms. J. Mol. Biol., in the press.Google Scholar
Suyama, Y. & Bonner, D. M. (1964). Complementation between trytophan synthetase mutants of Neurospora crassa. Biochem. biophys. Acta, 81, 565–575.Google Scholar
Vogel, H. J. (1958). A convenient growth medium for Neurospora (Medium N). Microbial Genet. Bull. 13, 42.Google Scholar
Westergaard, M. & Mitchell, H. K. (1947). Neurospora. V. A synthetic medium favouring sexual reproduction. Amer. J. Bot. 34, 573.CrossRefGoogle Scholar