Abstract
RAD55 belongs to a group of genes required for resistance to ionizing radiation, RAD50-RAD57, which are thought to define a pathway of recombinational repair. Since all four alleles of RAD55 are temperature conditional (cold sensitive) for their radiation phenotype, we investigated the phenotype produced by null mutations in the RAD55 gene, constructed in vitro and transplaced to the yeast chromosome. The X-ray sensitivity of these null mutant strains was surprisingly suppressed by increased temperature, osmotic strength of the growth medium and heterozygosity at the mating-type locus. These first two properties, temperature conditionality and osmotic remediability, are commonly associated with missense mutations; these rad55 null mutants are unique in that they exhibit these properties although the mutant gene cannot be expressed. X-ray-induced mitotic recombination was also cold sensitive in rad55 mutant diploids. Although mitotic growth was unaffected in these strains, meiosis was a lethal event at both high and low temperatures. Whereas the phenotype of rad55 null mutants is consistent with a role of RAD55 in recombination and recombinational repair, there is evidence for considerable RAD55-independent recombination, at least in mitotic cells, which is influenced by temperature and MAT . We discuss models for the role of RAD55 in recombination to explain the unusual properties of rad55 mutants.
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Selected References
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- Baker B. S., Carpenter A. T., Esposito M. S., Esposito R. E., Sandler L. The genetic control of meiosis. Annu Rev Genet. 1976;10:53–134. doi: 10.1146/annurev.ge.10.120176.000413. [DOI] [PubMed] [Google Scholar]
- Brendel M., Haynes R. H. Interactions among genes controlling sensitivity to radiation and alkylation in yeast. Mol Gen Genet. 1973 Sep 12;125(3):197–216. doi: 10.1007/BF00270743. [DOI] [PubMed] [Google Scholar]
- Broach J. R., Strathern J. N., Hicks J. B. Transformation in yeast: development of a hybrid cloning vector and isolation of the CAN1 gene. Gene. 1979 Dec;8(1):121–133. doi: 10.1016/0378-1119(79)90012-x. [DOI] [PubMed] [Google Scholar]
- Clark A. J., Sandler S. J., Willis D. K., Chu C. C., Blanar M. A., Lovett S. T. Genes of the RecE and RecF pathways of conjugational recombination in Escherichia coli. Cold Spring Harb Symp Quant Biol. 1984;49:453–462. doi: 10.1101/sqb.1984.049.01.051. [DOI] [PubMed] [Google Scholar]
- Game J. C., Mortimer R. K. A genetic study of x-ray sensitive mutants in yeast. Mutat Res. 1974 Sep;24(3):281–292. doi: 10.1016/0027-5107(74)90176-6. [DOI] [PubMed] [Google Scholar]
- Guthrie C., Nashimoto H., Nomura M. Structure and function of E. coli ribosomes. 8. Cold-sensitive mutants defective in ribosome assembly. Proc Natl Acad Sci U S A. 1969 Jun;63(2):384–391. doi: 10.1073/pnas.63.2.384. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ito H., Fukuda Y., Murata K., Kimura A. Transformation of intact yeast cells treated with alkali cations. J Bacteriol. 1983 Jan;153(1):163–168. doi: 10.1128/jb.153.1.163-168.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kassir Y., Simchen G. Regulation of mating and meiosis in yeast by the mating-type region. Genetics. 1976 Feb;82(2):187–206. doi: 10.1093/genetics/82.2.187. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lemontt J. F. Genetic and physiological factors affecting repair and mutagenesis in yeast. Basic Life Sci. 1980;15:85–120. doi: 10.1007/978-1-4684-3842-0_7. [DOI] [PubMed] [Google Scholar]
- SCHERAGA H. A., NEMETHY G., STEINBERG I. Z. The contribution of hydrophobic bonds to the thermal stability of protein conformations. J Biol Chem. 1962 Aug;237:2506–2508. [PubMed] [Google Scholar]