Dictyostelium discoideum strain M28, which has been used widely in genetic studies, was found to carry a radiation-sensitive mutation. This allele, termed rad-100, was recessive in heterozygous diploids and mapped in linkage group III. Complementation analysis and survival studies on strains carrying rad-100 suggested that this allele defines a new radiation-sensitive locus in D. discoideum, and this locus has been designated radE. radE strains were moderately sensitive to ultraviolet light (D10 90 J m−2) and slightly sensitive to 137Cs gamma rays (D10 255 krad). radE strains also exhibited increased sensitivity to killing by N-methyl-N′-nitro-N-nitrosoguanidine but not by other alkylating agents such as ethyl methanesulphonate or methyl methanesulphonate. The frequency of spontaneous methanol-resistant (acrA) mutants was approximately the same in cultures of radE and radE+ strains. However, when amoebae of these strains were irradiated with ultraviolet light, the frequency of induced mutants was significantly lower in cultures of the radE strain. Furthermore, when amoebae of wild-type strain NC4 were plated in the presence of caffeine after ultraviolet-irradiation, the survival curves were very similar to the curves obtained for amoebae of radE strains in the presence or in the absence of caffeine. These results suggest that the radE100 mutation and caffeine interfere with an error-prone DNA repair pathway in D. discoideum.
CoukellM.B.,
RoxbyN.M.1977; Linkage analysis of
developmental mutations in aggregation-deficient mutants of
Dictyostelium discoideum.
. Molecular and General Genetics 151:275–288
CoxB.S.,
ParryJ.M.1968; The isolation,
genetics and survival characteristics of ultraviolet light-sensitive
mutants in yeast. Mutation Research 6:37–55
FabreF.1972; Relation between repair mechanisms
and induced mitotic recombination after UV irradiation, in the yeast
Schizosaccharomyces pombe. Effects of
caffeine. Molecular and General
Genetics 117:153–166
HannanM.A.,
NasimA.1977; Caffeine enhancement
of radiation killing in different strains of Saccharomyces
cerevisiae.
. Molecular and General
Genetics 158:111–116
KatzE.R.,
SussmanM.1972; Parasexual
recombination in Dictyostelium discoideum: selection
of stable diploid heterozygotes and stable haploid
segregants. Proceedings of the National
Academy of Sciences of the United States of America 69:495–498
KihlmanB.A.,
SturelidS.,
Hartley-AspB.,
NilssonK.1974; The
enhancement by caffeine of the frequencies of chromosomal aberrations
induced in plant and animal cells by chemical and physical
agents. Mutation Research 26:105–122
LiwerantI.J.,
Pereira Da SilvaL.H.1975; Comparative mutagenic effects of
ethyl methane sulfonate,
N-methyl-N′-nitro-N-nitrosoguanidine,
ultraviolet radiation and caffeine on Dictyostelium
discoideum.
. Mutation
Research 33:135–146
McCormickJ.J.,
MarksC.,
RuschH.P.1972; DNA repair after
ultraviolet irradiation in synchronous plasmodia of Physarum
polycephalum.
. Biochimica et
biophysica acta 287:246–255
MossesD.,
WilliamsK.L.,
NewellP.C.1975; The use of
mitotic crossing-over for genetic analysis in Dictyostelium
discoideum: mapping of linkage group II. Journal of General Microbiology 90:247–259
NewellP.C.,
HendersonR.F.,
MossesD.,
RatnerD.I.1977; Sensitivity to Bacillus
subtilis: a novel system for selection of heterozygous
diploids of Dictyostelium
discoideum.
. Journal of General
Microbiology 100:207–211
RatnerD.I.,
NewellP.C.1979; Linkage analysis in
Dictyostelium discoideum using multiply marked
tester strains: establishment of linkage group VII and the
reassessment of earlier linkage data. Journal
of General Microbiology 109:225–236
SussmanM.,
SussmanR.R.1962; Ploidal inheritance
in Dictyostelium discoideum: stable haploid, stable
diploid and metastable strains. Journal of
General Microbiology 28:417–420
Van De PutteP.,
Van
SluisC.A.,
Van Dille-wijnJ.,
RorschA.1965; The localization of genes
controlling radiation sensitivity in Escherichia
coli.
. Mutation Research 2:97–110
WelkerD.L.,
DeeringR.A.1976; Genetic analysis of
radiation-sensitive mutations in the slime mould
Dictyostelium discoideum.
. Journal of General Microbiology 91:1–10
WelkerD.L.,
DeeringR.A.1978; Genetics of
radiation sensitivity in the slime mould Dictyostelium
discoideum.
. Journal of General
Microbiology 109:11–23
WilliamsK.L.,
KessinR.H.,
NewellP.C.1974; Parasexual
genetics in Dictyostelium discoideum: mitotic
analysis of acriflavin resistance and growth in axenic
medium. Journal of General
Microbiology 84:59–69