Mutations affecting the initiation of plasmodial development in Physarum polycephalum

Gorman, Jessica A.; Dove, William F.; Shaibe, Eva

doi:10.1002/dvg.1020010106

Cited by 20 publications

(10 citation statements)

References 30 publications

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“…The progeny of only a minority of the Het~ mutants had the rapid-selfing phenotypes, whereas the progeny of the majority only selfed rarely or apparently not at all. Adler & Holt (1977) and Gorman et al (1979) report similar results with other selfing mutants. Most of the original Het~ mutations may not have resulted in a rapid selfing phenotype.…”

Section: Discussionsupporting

confidence: 89%

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Selfing mutants from heterothallic strains ofPhysarum polycephalum

1981

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Plasmodial formation in the myxomycete Physarum polycephalum is controlled by a mating type (mt) locus, with heterothallic amoebae normally being unable to form plasmodia in pure clones. We report the isolation by mutagenesis of selfing mutants from heterothallic strains, and their analysis. Various amoebal strains of different mating types were mutagenized with a range of mutagens, and a number of selfing mutants (designated Het~) were isolated. A specific sensitivity of mt 2 amoebae to mutagenesis by NMG was observed. This sensitivity segregated as a single locus closely linked or allelic to the mt 2 locus. When the Hetc lones were incubated at 30 °C, selfing was greatly inhibited. This property was used to determine the mt specificities of four Het~ clones. The process of plasmodial induction in pure clones of CL was also studied using the 30 °C temperature effect.

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Section: Discussionsupporting

confidence: 89%

“…As these mutants have lost their heterothallic controls over plasmodial formation, they are designated as Het~. A preliminary report of this work has been made in abstract (Poulter, Honey & Teale, 1977), and similar results have also been reported by Adler & Holt (1977) and Gorman, Dove & Shaibe (1979).…”

Section: Introductionsupporting

confidence: 64%

Selfing mutants from heterothallic strains ofPhysarum polycephalum

1981

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“…Although selfing normally occurs in heterothallic strains only very rarely, certain mutations can bring about selfing phenotypes similar to that of matAh amoebae Gorman, Dove & Shaibe, 1979;Honey, Poulter & Winter, 1981). We term such mutations gad, for greater asexual differentiation.…”

Section: Introductionmentioning

confidence: 97%

Map and function ofgadmutations inPhysarum polycephalum

1983

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Amoebae and plasmodia are alternate vegetative forms in the life cycle of the acellular slime mould Physarum polycephalum. Haploid amoebae carrying heterothallic alleles of the matA (or mt) locus ordinarily form plasmodia only by crossing, but occasionally give rise to mutants that form plasmodia by selfing as well as by crossing. Twelve independently isolated mutants of this type have been studied. Eight carry mutations (termed gad or greater asexual differentiation mutations) within approximately 02 map units of matA. Another mutation (gad-12) is linked neither to matA nor to any of 9 other markers tested. The remaining three mutations are linked to matA and map as follows: matA-05 units -gad-4-4 units -gad-6 -8 units -gad-11. One mutation, gad-11, has been tested in strains carrying each of the five matA alleles (matAl, 2, 3, 4, and h) available in a common genetic background; the mutation is expressed with all five alleles. The mutation npfFl (formerly aptAl), which was isolated as a suppressor of selfing in Colonia (mat Ah) amoebae, suppresses the action of each of the 12 gad mutations. The similarly isolated mutation npfAl is also epistatic to eight of the mutations, but permits selfing with gad-5, 6, 12 and 13. For double mutant strains containing gad-12 and gad-1,2, 4,6 or 11, the selfing behaviour of each double mutant differs from that of either single mutant. Mixtures of gad~ npfFl with gad + npf* amoebae readily form plasmodia, a result suggesting that gad mutations are dominant or semi-dominant. We conclude that the commitment of a cell to differentiate into a plasmodium is under the control of a complex group of genes linked to matA.

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“…These mutations, designated gad (greater asexual differentiation) or alc (amoeba-less life cycle), allow haploid amoebae to self at high frequency. All but one of 29 gad mutations showed an absence of recombination with matA when small numbers of progeny were tested (typically 20-60;Adler & Holt, 1977;Gorman et al, 1979). Shinnick et al (1983) subjected eleven of the matA-linked mutations to more detailed analysis and again found no evidence of recombination between matA and eight of the mutations; it was concluded that each of these mutations lay within about 0.2 cM of matA.…”

Section: Introductionmentioning

confidence: 99%

“…Using such temperatures to inhibit selfing, it has been shown that gadA mutants retain the ability to cross with non-mutant strains. The mutants usually show the same mating specificities in these crosses as their parents, crossing only with strains carrying nonparental matA alleles (Adler & Holt, 1977;Gorman et al, 1979;Honey e? al., 1981).…”

Section: Introductionmentioning

confidence: 99%

Regulation of Development by the matA Complex Locus in Physarum polycephalum

et al. 1989

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1347 ~The transformation of uninucleate amoebae of Physarum polycephalum into multinucleate plasmodia is under the control of a multiallelic mating-type locus, matA. Plasmodium formation usually occurs only when amoebal fusion brings together two different matA alleles within a single cell; such plasmodium formation is termed crossing. Mutations (gadA) in the matA locus permit haploid amoebae to self, that is to form plasmodia in clonal cultures without amoebal fusion. By constructing diploid amoebae heterozygous for gadA alleles, it was shown that the mutant alleles gadA.5 and gadAl1 I were each dominant to gadA+. Non-selfing revertants of gadA mutants may be generated as a result of further mutations (npf) within the matA locus. Sixty-one revertants of this type were studied, derived from three matA3 gadA mutants. Some revertants were able to cross with a matA3 gadA+ tester strain. These 'class I' revertants failed to cross with one another or with similar revertants of two matA2 gadA mutants; they appear all to lack a single gene function (npfC+) that is necessary in plasmodium development. Other revertants failed to cross with the matA3 gadA+ tester. These 'class 11' revertants also failed to cross with one another, but showed several different patterns of crossing when mixed with other strains. The behaviour of some of the class I1 revertants suggests that they lack a further gene function (npfB+) necessary in plasmodium development. The gadA mutations may affect a cisacting regulator of npfB+.

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Mutations affecting the initiation of plasmodial development in Physarum polycephalum

Cited by 20 publications

References 30 publications

Selfing mutants from heterothallic strains ofPhysarum polycephalum

Selfing mutants from heterothallic strains ofPhysarum polycephalum

Map and function ofgadmutations inPhysarum polycephalum

Regulation of Development by the matA Complex Locus in Physarum polycephalum

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