1887

Abstract

The virally encoded K28 killer toxin of kills sensitive cells by a receptor-mediated process. DNA synthesis is rapidly inhibited, cell viability is lost more slowly and cells eventually arrest, apparently in the S phase of the cell cycle with a medium-sized bud, a single nucleus in the mother cell and a pre-replicated (1n) DNA content. Cytoplasmic microtubules appear normal, and no spindle is detectable. Arrest of a sensitive haploid yeast strain by α-factor at START gave complete protection for at least 4 h against a toxin concentration that killed non-arrested cells at the rate of one log each 2.5 h. Cells released from α-factor arrest were killed by toxin at a similar rate; arrest occurred with medium-sized buds within the same cell cycle. Cells arrested by hydroxyurea, with unreplicated DNA, or by the spindle poison methylbenzimidazol-2yl-carbamate, with unseparated chromosomes, both arrest at the checkpoint at the G2/M boundary; these arrested cells were not protected against toxin, losing about one log of viability every 4 h. Following release from the cell cycle block, a majority of these toxin-exposed cells progressed through the cell cycle and arrested in the following S-phase, again with medium-sized buds. Killing by K28 toxin apparently requires entry into the nuclear division and bud cycles, but can result from inhibition of either early or late events in these cycles. Morphogenesis in moribund cells is uniformly blocked in early S-phase with an immature bud. Toxin action causes either independent blockage of both DNA synthesis and the budding cycle, or inhibits some unknown step required for both events.

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/content/journal/micro/10.1099/00221287-142-9-2655
1996-09-01
2021-07-24
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References

  1. Bakalinsky A. T., Snow R. 1990; Conversion of wine strains of Saccharomyces cerevisiae to heterothallism. Appl Environ Microbiol 56:849–857
    [Google Scholar]
  2. Baum P., Yip C., Goetsch L., Byers B. 1988; A yeast gene essential for regulation of spindle pule duplication. Mol Cell Biol 8:5386–5397
    [Google Scholar]
  3. Bostian K. A., Elliot Q., Bussey H., Burn V., Smith A., Tipper D. J. 1984; Sequence of the preprotoxin dsRNA gene of type 1 killer yeast: multiple processing events produce a two component toxin. Cell 36:741–751
    [Google Scholar]
  4. Bussey H. 1991; K1 killer toxin: a pore-forming protein from veasr. Mol Microbiol 5:2339–2343
    [Google Scholar]
  5. Butler A. R., White J. H., Stark M. J. R. 1991; Analysis of the response of Saccharomyces cerevisiae cells to Kluyveramyces iactis toxin. J Gen Microbiol 151:l749–1757
    [Google Scholar]
  6. Dignard D., Whiteway M., Germain D., Tessier D., Thomas D. Y. 1991; Expression in yeast of a cDNA copy of the K2 killer toxin gene. Mol Gen Genet 227:127–136
    [Google Scholar]
  7. Foiani M., Marini F., Gamba D., Lucchini G., Plevani P. 1994; The B subunit of the DNA polymerase α-primase complex in Saccharomyces cerevisiae executes an essential function at the initial stage of DNA replication. Mol Cell Biol 14:923–933
    [Google Scholar]
  8. Foiani M., Liberi G., Lucchini G., Plevani P. 1995; Cell cycle-dependent phosphorylation and dephosphorylation of the yeast DNA polymerase α-primase B subunit. Mol Cell Biol 15:883–891
    [Google Scholar]
  9. Hanes S. D., Burn V. E., Sturley S. L., Tipper D. J., Bostian K. A. 1986; Expression of a cDNA derived from the yeast killer preprotoxin gene: implications for processing and immunity. Proc Natl Acad Set USA 83:1675–1679
    [Google Scholar]
  10. Hutchins K., Bussey H. 1983; Cell wall receptor of yeast killer toxin: involvement of l,6-β-d-glucan. J Bacteriol 154:161–169
    [Google Scholar]
  11. Martinac B., Zhu H., Kubalski A., Zhou X., Culbertson M., Bussey H., King C. 1990; Yeast K1 killer toxin forms ion channels in sensitive yeast spheroplasts and in artificial liposomes. Proc Natl Acad Sci USA 876228–6232
    [Google Scholar]
  12. Murray A. W., Hunt T. 1993 The Cell Cycle New York: W. H. Freeman;
    [Google Scholar]
  13. Pfeiffer P., Radler F. 1982; Purification and characterization of extracellular and intracellular killer toxin of Saccharomyces cerevisiae strain 28. J Gen Microbiol 128:2699–2706
    [Google Scholar]
  14. Pringle J. R., Preston R. A., Adams A. E. M., Haarer B. K., Jones E. W. 1991; Immunofluorescence methods for yeast. Methods Enzymol 194:565–602
    [Google Scholar]
  15. Schmitt M. J. 1995; Cloning and expression of a cDNA copy of the viral K28 killer toxin gene in yeast. Mol Gen Genet 246:236–246
    [Google Scholar]
  16. Schmitt M. J., Compain P. 1995; Kilier toxin resistant kre12 mutants of Saccharomyces cerevisiae: genetic and biochemical evidence for a secondary K1 membrane receptor. Arch Microbiol 164:435–443
    [Google Scholar]
  17. Schmitt M. J., Radler F. 1987; Mannoprotein of the yeast cell wall as primary receptor for the killer toxin of Saccharomyces cerevisiae strain 28. J Gen Microbiol 133:3347–3354
    [Google Scholar]
  18. Schmitt M. J., Radler F. 1988; Molecular structure of the cell wall receptor for killer toxin K28 in Saccharomyces cerevisiae. . J Bacteriol 170:2192–2196
    [Google Scholar]
  19. Schmitt M. J., Tipper D. J. 1990; K28, a unique doublestranded RNA killer virus of Saccharomyces cerevisiae. . Mol Cell Biol 10:4807–4815
    [Google Scholar]
  20. Schmitt M. J., Tipper D. J. 1995; Sequence of the M28 dsRNA: preprotoxin is processed to an α/β-heterodimeric protein toxin. Virology 213:341–351
    [Google Scholar]
  21. Schmitt M. J., Brendel M., Schwarz R., Radler F. 1989; Inhibition of DN A synthesis in Saccharomyces cerevisiae by yeast killer toxin K28. J Gen Microbiol 135:1529–1535
    [Google Scholar]
  22. Tipper D. J., Schmitt M. J. 1991; Yeast dsRNA viruses: replication and killer phenotypes. Mol Microbiol 5:2331–2338
    [Google Scholar]
  23. Weinert T. A., Hartwell L. H. 1990; Characterization of KAD9 of Saccharomyces cerevisiae and evidence that its function acts posttranslationally in cell cycle arrest after DNA damage. Mol Cell Biol 10:6554–6564
    [Google Scholar]
  24. Wickner R. B. 1992; Double-stranded and single-stranded RNA viruses of Saccharomyces cerevisiae. . Annu Rev Microbiol 46:347–375
    [Google Scholar]
  25. Wickner R. B. 1993; Double-stranded RNA virus replication and packaging. J Biol Chem 268:3797–3800
    [Google Scholar]
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