Abstract
It has been shown previously that the radiation sensitivity of LexA− strains of Escherichia coli K-12 can be suppressed by thermosensitive mutations (designated tsl) that are closely linked to the lexA locus. These are thought to be intragenic suppressors that reduce the activity of the diffusible product that gives rise to the LexA−phenotype (Mount et al., 1973). When a recA mutation is crossed into a suppressed tsl − strain, the extreme radiation sensitivity usually conferred by a recA mutation is considerably reduced without any detectable change in genetic recombination deficiency. Suppression of UV sensitivity depends upon the activity of the uvrA + product. We propose that at least part of the radiation sensitivity of a recA − strain is due to a DNA repair defect that is different from inability to perform genetic exchanges and depends upon the presence of the lexA + product. We hypothesize that the lexA + product is a repressor of the synthesis of repair enzymes. In recA + cells with DNA lesions, repressor is inactivated leading to enzyme induction but this does not occur in recA − cells. tsl mutations inactivate repressor leading to constitutive enzyme synthesis and bypassing the need for recA + product to inactivate the lexA + product.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Adler, H. I. and Hardigree, A. A. (1964). J. Bacteriol. 87, 220–226.
Bridges, B. A. (1973). Genetics 73 (suppl), 123–129.
Brooks, K. and Clark, A. J. (1967). J. Virol. 1, 283–293.
Castellazzi, M., George, J. and Buttin, G. (1972). Mol. Gen. Genet. 119, 153–174.
Clark, A. J. (1973). Ann Rev. Genet. 7, 67–86.
Defais, M., Faguet, P. and Radman, M. (1971). Virology 43, 495–503.
Donch, J. J. and Greenberg, J. (1974). Mol. Gen. Genet. 128, 277–281.
Ganesan, A. K. and Smith, K. C. (1968). Cold Spring Harbor Symp. Quant. Biol. 33, 235–242.
Howard-Flanders, P., Simson, E. and Theriot, L. (1964). Genetics 49, 237–246.
Howard-Flanders, P., Theriot, L. and Stedeford, J. B. (1969). J. Bacteriol. 97, 1134–1141.
Moody, E. E. M., Low, K. B. and Mount, D. W. (1973). Mol. Gen. Genet. 121, 197–205.
Mount, D. W., Low, K. B. and Edmiston, S. J. (1972). J. Bacteriol. 112, 886–893.
Mount, D. W., Walker, A. C. and Kosel, C. (1973). J. Bacteriol. 116, 950–956.
Radman, M. (1974). In Molecular and Environmental Aspects of Mutagenesis (Miller, M., ed.), Thomas, Springfield (in press).
Rupp, W. D., and Howard-Flanders, P. (1968). J. Mol. Biol. 31, 291–304.
Rupp, W. D., Wilde, C. E., Reno, D. L. and Howard-Flanders, P. (1971). J. Mol. Biol. 61, 25–44.
Sedgwick, S. G. and Bridges, B. A. (1972). Mol. Gen. Genet. 119, 93–102.
Smith, D. C. and Meun, D. H. C. (1970). J. Mol. Biol. 51, 459–472.
Taylor, A. L. and Trotter, C. D. (1970). Bacteriol. Rev. 36, 504–524.
Witkin, E. M. and George D. L. (1973). Genetics 73 (suppl.), 91–108.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1975 Plenum Press, New York
About this chapter
Cite this chapter
Mount, D.W., Walker, A.C., Kosel, C. (1975). Indirect Suppression of Radiation Sensitivity of a recA − Strain of Escherichia coli K12. In: Hanawalt, P.C., Setlow, R.B. (eds) Molecular Mechanisms for Repair of DNA. Basic Life Sciences. Springer, Boston, MA. https://doi.org/10.1007/978-1-4684-2895-7_51
Download citation
DOI: https://doi.org/10.1007/978-1-4684-2895-7_51
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4684-2897-1
Online ISBN: 978-1-4684-2895-7
eBook Packages: Springer Book Archive