Summary
We have mapped 17 extragenic suppressors of benA 33, a heat-sensitive β-tubulin mutation of Aspergillus nidulans, to the tubA α tubulin locus. Fifteen of these tubA mutations cause cold sensitivity in a genetic background with benA 33 and appear to cause lethality in a background with the wild-type benA allele. We examined the microtubule-mediated processes, nuclear division and nuclear migration, in seven different cold-sensitive double mutants, each carrying benA 33 and a different cold-sensitive tubA allele. Nuclear division and migration were inhibited at a restrictive temperature in each case, suggesting that cold sensitivity is due to the inhibition of microtubule function at low temperatures. A single allele, tubA4, suppressed the heat sensitivity conferred by benA33 but did not confer cold sensitivity in a benA33 background, however in a wildtype benA background, tubA4 conferred supersensitivity to antimicrotubule agents and weak cold sensitivity. TubA4 did not suppress the heat sensitivity conferred by two other benA alleles. The cold sensitivity conferred by tubA4 was suppressed by the microtubule stabilizing agent deuterium oxide, and the suppression of heat sensitivity conferred by four other tubA mutations was reversed by deuterium oxide. These results suggest that these mutations may affect hydrophobic interactions between α-and β-tubulin.
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Abraham I, Marcus M, Cabral F, Gottesman MM (1983) Mutations in α-and β-tubulin affect spindle formation in Chinese hamster ovary cells. J Cell Biol 97:1055–1061
Cabral F, Abraham I, Gottesman MM (1981) Isolation of a taxolresistant Chinese hamster ovary cell mutant that has an alteration in α-tubulin. Proc Natl Acad Sci USA 78:4388–4391
Cabral F, Abraham I, Gottesman MM (1982) Revertants of a Chinese hamster ovary cell mutant with an altered β-tubulin: Evidence that the altered tubulin confers both colcemid resistance and temperature sensitivity on the cell. Mol Cell Biol 2:720–729
Gambino J, Bergen LG, Morris NR (1984) Effects of mitotic and tubulin mutations on microtubule architecture in actively growing protoplasts of Aspergillus nidulans. J Cell Biol 99:830–838
Hiraoka Y, Toda T, Yanagida M (1984) The NAD 3 gene of fission yeast encodes β-tubulin: A cold-sensitive nda3 mutation reversibly blocks spindle formation and chromosome movement in mitosis. Cell 39:349–358
Itoh TJ, Sato H (1984) The effects of Deuterium Oxide (2H2O) on the polymerization of tubulin in vitro. Biochim Biophys Acta 800:21–27
Jarvik J, Botstein D (1975) Conditional-lethal mutations that suppress genetic defects in morphogenesis by altering structural proteins. Proc Natl Acad Sci USA 72:2738–2742
Morris NR, Lai MH, Oakley CE (1979) Identification of a gene for α-tubulin in Aspergillus nidulans. Cell 16:437–442
Neff NF, Thomas JH, Grisafi P, Botstein D (1983) Isolation of the β-tubulin gene from yeast and demonstration of its essential function in vivo. Cell 33:211–219
Oakley BR, Morris NR (1980) Nuclear movement is β-tubulin dependent in Aspergillus nidulans. Cell 19:255–262
Oakley BR, Morris NR (1981) A β-tubulin mutation in Aspergillus nidulans that blocks microtubule function without blocking assembly. Cell 24:837–845
Oakley BR, Oakley CE, Kniepkamp KS, Rinehart JE (1985) Isolation and characterization of cold-sensitive mutations at the benA, β-tubulin, locus of Aspergillus nidulans. Mol Gen Genet 201:56–64
Raff EC (1984) Genetics of microtubule systems. J Cell Biol 99:1–10
Schiff PB, Horwitz SB (1980) Taxol stabilizes microtubules in mouse fibroblast cells. Proc Natl Acad Sci USA 77:1561–1565
Sheir-Neiss G, Lai M, Morris, NR (1978) Identification of a gene for β-tubulin in Aspergillus nidulans. Cell 15:639–647
Thomas JH, Novick P, Botstein D (1984) Genetics of the yeast cytoskeleton. In: Borisy GG, Cleveland DW, Murphy DB (eds) Molecular biology of the cytoskeleton. Cold Spring Harbor Press, Cold Spring Harbor, New York, pp 153–174
Thomas JH, Neff NF, Botstein D (1985) Isolation and characterization of mutations in the β-tubulin gene of Saccharomyces cerevisiae. Genetics 112:715–734.
Toda T, Adachi Y, Hiraoka Y, Yanagida M (1984) Identification of the pleiotropic cell cycle gene NDA2 as one of two different α-tubulin genes in Schizosaccharomyces pombe. Cell 37:233–242
Weatherbee JA, Morris NR (1984) Aspergillus contains multiple tubulin genes. J Biol Chem 259:15452–15459
Weil CF, Oakley CE, Oakley BR (1986) Isolation of mip (microtubule interacting protein) mutations of Aspergillus nidulans. Mol Cell Biol 6:2963–2968
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Communicated by C.P. Hollenberg
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Oakley, B.R., Oakley, C.E. & Rinehart, J.E. Conditionally lethal tubA α-tubulin mutations in Aspergillus nidulans . Mole Gen Genet 208, 135–144 (1987). https://doi.org/10.1007/BF00330434
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DOI: https://doi.org/10.1007/BF00330434