1887

Abstract

In , uninucleate haploid amoebae develop into macroscopic multinucleate plasmodia. Wild-type, sexual development is triggered when two amoebae carrying different alleles of fuse to form a zygote which develops into a diploid plasmodium. Mutations in the genetic region give rise to apogamic strains in which a single haploid amoeba can develop into a haploid plasmodium. An essential stage in both sexual and apogamic plasmodium formation is an extended cell cycle in uninucleate cells, which ends with the formation of a binucleate cell by mitosis without cytokinesis. Using a ‘brute force’ screening method, we have isolated mutants blocked in apogamic plasmodium development. Genetic analysis showed that the mutations we have identified were unlinked to , unlike mutations previously identified following an enrichment step. Most of the loci revealed by our screen were represented by only one allele, indicating that further screening should lead to the identification of additional genes required for plasmodium development. Phenotypic analysis showed that different mutants were blocked at different stages of plasmodium formation. Some of the mutations blocking apogamic development at an early stage, close to the start of the long cell cycle, failed to block sexual development in zygotes homozygous for the mutation. Since the two modes of plasmodium formation differ only in the initiation of development, these mutations presumably interfere with the initiation process. In the remaining mutants, in which both sexual and apogamic development were blocked, development first became abnormal towards the end of the long cell cycle. This suggested that the wild-type gene products were required by this time and was consistent with previous evidence that many changes in cellular organization and gene expression occur during the long cell cycle. Each of these mutants showed a different terminal phenotype and some aspects of plasmodium development occurred normally although others were blocked, suggesting that development involves multiple pathways rather than a dependent sequence of events. Phenotypic analysis of double mutants supported this conclusion and also revealed epistatic interactions, presumably due to blocks in the same pathway. In several of the mutants, terminally differentiated cells died by an apoptosis-like mechanism; since this was never observed in vegetative cells, it was presumably triggered by the failure of development. Phenotypic analyses of additional mutants will extend our understanding of the pathways involved in plasmodium development.

Loading

Article metrics loading...

/content/journal/micro/10.1099/13500872-141-4-799
1995-04-01
2021-10-22
Loading full text...

Full text loading...

/deliver/fulltext/micro/141/4/mic-141-4-799.html?itemId=/content/journal/micro/10.1099/13500872-141-4-799&mimeType=html&fmt=ahah

References

  1. Anderson R. W. 1979; Complementation of amoebal-plasmodial transition mutants in Phjsarum polycephalum . Genetics 91: 409– 419
    [Google Scholar]
  2. Anderson R. W., Dee J. 1977; Isolation and analysis of amoebal–plasmodial transition mutants in the myxomycete Phjsarum polycephalum . Genet Res Camb 29: 21–34
    [Google Scholar]
  3. Anderson R. W., Holt C. E. 1981; Revertants of selfing (gad) mutants in Phjsarum polycephalum . Dev Genet 2: 253– 267
    [Google Scholar]
  4. Anderson R. W., Hutchins G., Gray A., Price J., Anderson S. E. 1989; Regulation of development by the matA complex locus in Physarum polycephalum . J Gen Microbiol 135: 1347–1359
    [Google Scholar]
  5. Bailey J., Anderson R. W., Dee J. 1987; Growth and differentiation in relation to the cell cycle in Physarum polycephalum . Protoplasma 141: 101–111
    [Google Scholar]
  6. Bailey J., Anderson R. W., Dee J. 1990; Cellular events during sexual development from amoeba to plasmodium in the slime mould Phjsarum polycephalum . J Gen Microbiol 135:739–751
    [Google Scholar]
  7. Bailey J., Solnica-Krezel L., Anderson R. W., Dee J. 1992a; A developmental mutation (npfL1) resulting in cell death in Phjsarum polycephalum . J Gen Microbiol 138: 2575–2588
    [Google Scholar]
  8. Bailey J., Solnica-Krezel L., Lohman K., Dee J., Anderson R. W., Dove W. F. 1992b; Cellular and molecular analysis of plasmodium development in Physarum . Cell Biol Int Rep 16: 1083–1090
    [Google Scholar]
  9. Birkett C. R., Foster K. E., Johnson L., Gull K. 1985; Use of monoclonal antibodies to analyze the expression of a multi-tubulin family. FEBS Lett 187:211–218
    [Google Scholar]
  10. Blindt A. B., Chainey A. M., Dee J., Gull K. 1986; Events in the amoebal–plasmodial transition of Physarum polycephalum studied by enrichment for committed cells. Protoplasma 132: 149–159
    [Google Scholar]
  11. Burland T. G., Chainey A. M., Dee J., Foxon J. L. 1981; Analysis of development and growth in a mutant of Physarum polycephalum with defective cytokinesis. Dev Biol 85:26–38
    [Google Scholar]
  12. Burland T. G., Schedl T., Gull K., Dove W. F. 1984; Genetic analysis of resistance to benzidimazoles in Physarum: differential expression of β -tubulin genes. Genetics 108:123–141
    [Google Scholar]
  13. Burland T. G., Paul E. C. A., Oetliker M., Dove W. F. 1988; A gene encoding the major beta-tubulin of the mitotic spindle in Physarum polycephalum plasmodia. Mol Cell Biol 8:1275–1281
    [Google Scholar]
  14. Burland T. G., Bailey J., Adam L., Mukhopadhyay M. J., Dove W. F., Pallotta D. 1992a; Transient expression in Physarum of a chloramphenicol acetyltransferase gene under the control of actin gene promoters. Curr Genet 21:393–398
    [Google Scholar]
  15. Burland T. G., Bailey J., Dove W. F., Mukhopadhyay M. J., Pallotta D. 1992b; Methods for transient and stable expression of heterologous genes in Physarum . Cell Biol Int Reps 16:1111–1117
    [Google Scholar]
  16. Burland T. G., Bailey J., Pallotta D., Dove W. F. 1993; Stable, selective, integrative DNA transformation in Physarum . Gene 132:207–212
    [Google Scholar]
  17. Collett J. I., Holt C. E., Huttermann A. 1983; Plasmodium formation in Physarum polycephalum: cytological events and their timing relative to commitment. Cell Biol Int Rep 7:819–825
    [Google Scholar]
  18. Cooke D. J., Dee J. 1974; Plasmodium formation without change in nuclear DNA content in Physarum polycephalum . Genet Res 23: 307–317
    [Google Scholar]
  19. Davidow L. S., Holt C. E. 1977; Mutants with decreased differentiation to plasmodia in Physarum polycephalum . Mol & Gen Genet 155: 291–300
    [Google Scholar]
  20. Dee J. 1986 The culture of Physarum amoebae in axenic media. In The Molecular Biology of Physarum polycephalum pp 255–270 Edited by Dove W. F., Dee J., Hatano S., Haugli F. B., Wolfarth-Bottermann K.-E. New York: Plenum Press;
    [Google Scholar]
  21. Dee J. 1987; Genes and development in Physarum polycephalum . Trends Genet 3:208–213
    [Google Scholar]
  22. Diggins M., Dove W. F. 1987; Distribution of acetylated α- tubulin in Physarum polycephalum . J Cell Biol 104:303–309
    [Google Scholar]
  23. Diggins-Gilicinski M., Solnica-Krezel L., Burland T. G., Paul E. C. A., Dove W. F. 1989; The localization of the divergent β 2-tubulin isotype in the microtubular arrays of Physarum polycephalum . J Cell Sci 94:217–226
    [Google Scholar]
  24. Green L. L., Dove W. F. 1984; Tubulin proteins and RNA during the myxamoeba–flagellate transformation of Physarum polycephalum . Mol Cell Biol 4:1706–1711
    [Google Scholar]
  25. Havercroft J. C., Gull K. 1983; Demonstration of different patterns of microtubule organization in Physarum polycephalum myxamoebae and plasmodia using immunofluorescence microscopy. Eur J Cell Biol 32: 67–74
    [Google Scholar]
  26. Honey N. K., Poulter R. T. M., Teale D. M. 1979; Genetic regulation of differentiation in Physarum polycephalum . Genet Res 34: 131–142
    [Google Scholar]
  27. Honey N. K., Poulter R. T. M., Aston R. J. 1982; Non-selfing mutants from selfing (Het) strains of Physarum polycephalum . Genet Rer 39: 261–273
    [Google Scholar]
  28. Kawano S., Kuroiwa W., Anderson R. W. 1987; A third multiallelic mating-type locus in Physarum polycephalum . J Gen Microbiol 133: 2539– 2546
    [Google Scholar]
  29. Nusslein-Volhard C., Wieschaus E. 1980; Mutations affecting segment number and polarity in Drosophila . Nature 287:795–801
    [Google Scholar]
  30. Mullins M. C., Nusslein-Volhard C. 1993; Mutational approaches to studying embryonic pattern formation in the zebrafish. Curr Opin Genes Dev 3:648–654
    [Google Scholar]
  31. Pallotta D. J., Youngman P. J., Shinnick T. M., Holt C. E. 1979; Kinetics of mating in Physarum polycephalum . Mycologia 71:68–84
    [Google Scholar]
  32. Piperno G., Fuller M. T. 1985; Monoclonal antibodies specific for an acetylated α-tubulin in mammalian cells in culture. J Cell Biol 101:2085–2094
    [Google Scholar]
  33. Poulter R. T. M. 1969 Senescence in the myxomycete Physarum polycephalum PhD thesis, University of Leicester; UK:
    [Google Scholar]
  34. Sasse R., Glyn M. C. P., Birkett C. R., Gull K. 1987; Acetylated α-tubulin in Physarum: immunological characterization of the isotype and its usage in particular microtubular organelles. J Cell Biol 104:41–49
    [Google Scholar]
  35. Solnica-Krezel L., Dove W. F., Burland T. G. 1988; Activation of a β 2-tubulin gene during early development of the plasmodium in Physarum polycephalum . J Gen Microbiol 134: 1323–1331
    [Google Scholar]
  36. Solnica-Krezel L., Diggins-Gilicinski M., Burland T. G., Dove W. F. 1990; Variable pathways for developmental changes in composition and organization of microtubules in Physarum polycephalum . J Cell Sci 96: 383–393
    [Google Scholar]
  37. Solnica-Krezel L., Burland T. G., Dove W. F. 1991; Variable pathways for developmental changes in mitosis and cytokinesis in Physarum polycephalum . J Cell Biol 113: 591–604
    [Google Scholar]
  38. Sweeney G. E., Watts D. I., Turnock G. 1987; Differential gene expression during the amoebal–plasmodial transition in Physarum . Nucleic Acids Res 15: 933– 945
    [Google Scholar]
  39. Uyeda T. Q., Kohama K. 1987; Myosin switching during amoebo-plasmodial differentiation of slime mold, Physarum polycephalum . Exp Cell Res 169: 74–84
    [Google Scholar]
  40. Vaux D. L., Haecker G., Strasser A. 1994; An evolutionary perspective on apoptosis. Cell 76: 777–779
    [Google Scholar]
  41. Walden P. D., Blindt A. B., Birkett C. R., Cox R. A., Gull K. 1989; Recognition of specific Physarum α-tubulin isotypes by a monoclonal antibody. Eur J Biochem 185: 383–389
    [Google Scholar]
  42. Wheals A. E. 1973; Developmental mutants in a homothallic strain of Physarum polycephalum . Genet Res 21: 79– 86
    [Google Scholar]
  43. Wyllie A. H. 1988; Apoptosis. ISI Atlas Sci Immunol 1:192–196
    [Google Scholar]
  44. Youngman P. J., Adler P. N., Shinnick T. M., Holt C. E. 1977; An extracellular inducer of asexual plasmodial development in Physarum polycephalum . Proc Natl Acad Sci USA 74: 1120–1124
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/13500872-141-4-799
Loading
/content/journal/micro/10.1099/13500872-141-4-799
Loading

Data & Media loading...

Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error