Summary
The mechanism of the inhibition and of the recovery of DNA synthesis in E. coli following UV-irradiation was analysed in several mutants defective in repair or in the regulation of the RecA-LexA dependent SOS response. Several lines of evidence indicated that inhibition is not an inducible function and is probably due to the direct effect of lesions in the template blocking replisome movement.
Recovery of DNA synthesis after UV was largely unaffected by mutations in the uvrA, recB or umuC genes. Resumption of DNA synthesis does however require protein synthesis and the regulatory action of recA. Experiments with a recA constitutive mutant and recA 200 (temperature sensitive RecA) demonstrated that RecA protein itself is directly required but is not sufficient for recovery of DNA synthesis. We therefore propose that recovery of DNA synthesis depends upon the concerted activity of RecA and the synthesis of an inducible Irr (induced replisome reactivation) factor under RecA control. We suggest that the mechanism of recovery involves the action of Irr and RecA to promote movement of replisomes past non-instructive lesions, uncoupled from polymerisation and/or that Irr and RecA are required to promote re-initiation of a stalled replication complex downstream of a UV-lesion subsequent to such an uncoupling step.
Similar content being viewed by others
References
Billen D (1969) Replication of the bacterial chromosome: location of new initiation sites after irradiation. J Bacteriol 97:1169–1175
Burton P (1981) Two pathways for division inhibition in E. coli. B.Sc. (Medical School) University of Leicester
Burton P, Holland IB (1983) Two pathways of division inhibition in UV-irradiated E. coli. Mol Gen Genet 190:309–314
Caillet-Fauquet P, Defais M, Radman M (1977) Molecular mechanisms of induced mutagenesis: replication in vivo of bacteriophage ϕx174 single-stranded, ultraviolet light irradiated DNA in intact and irradiated host cells. J Mol Biol 117:95–112
Castellazzi M, George J, Buttin G (1972) Prophage induction and cell division in E. coli. I Further characterisation of the thermosensitive mutation tif-1 whose expression mimics the effect of UV irradiation. Mol Gen Genet 119:139–152
Cooper PK (1982) Characterisation of long patch excision repair of DNA in ultraviolet-irradiated E. coli: An inducible function under Rec-Lex control. Mol Gen Genet 185:189–197
Dannenberg R, Mosig G (1983) Early intermediates in bacteriophage T4 replication and recombination. J Virol 45:813–831
Darby V, Holland IB (1979) A kinetic analysis of cell division, and induction and stability of RecA protein in UV-irradiated lon + and lon - strains of E. coli K12. Mol Gen Genet 176:121–128
Doudney CO (1972) Chloramphenical effects on DNA replication in UV-damaged bacteria. Mut Res 17:1–12
Doudney CO (1973) Rifamycin limitation of DNA synthesis in ultraviolet damaged bacteria: Evidence for postirradiation replication synchrony. Biochem Biophys Acta 312:243–247
Elledge S, Walker GC (1983) Proteins required for ultraviolet light and chemical mutagenesis. J Mol Biol 164:175–192
Glickman BW, Guijt N, Morand P (1977) The genetic characterisation of lexB30, lexB33 and lexB35 mutations of E. coli: location and complementation pattern for UV resistance. Mol Gen Genet 157:83–89
Huisman O, D'Ari R, Gottesman S (1984) Cell division control in E. coli: Specific induction of the SOS function SfiA protein in sufficient to block septation. Proc Natl Acad Sci (USA) 81:4490–4495
Jonczyk P, Ciesla Z (1979) DNA synthesis in UV irradiated E. coli K12 strains carrying dnaA mutations. Mol Gen Genet 171:53–58
Kato T, Shinoura Y (1977) Isolation and characterisation of mutants of E. coli deficient in induction of mutations by ultraviolet light. Mol Gen Genet, 156:121–131
Kogoma T, Lark KG (1975) Characterisation of the replication of E. coli DNA in the absence of protein synthesis: stable DNA replication. J Mol Biol 94:243–256
Kogoma T, Torrey TA, Connaughton MJ (1979) Induction of UV resistant DNA replication in E. coli: Induced stable DNA replication as an SOS function. Mol Gen Genet 176:1–9
Kogoma T., Von Meyenburg K (1983) The origin of replication, oriC and the dnaA protein are dispensible in stable DNA replication (sdrA) mutants of E. coli K12. EMBO J 2:463–468
Lloyd RG, Low B, Godson N, Birge H (1974) Isolation and characterisation of an E. coli K12 mutant with a temperature sensitive Rec- phenotype. J Bacteriol 120:407–415
Luder A, Mosig G (1982) Two alternative mechanisms for DNA replication forks in bacteriophage T4: Priming by RNA polymerase and by recombination. Proc Natl Acad Sci (USA) 79:1101–1105
McEntee K, Weinstock GM, Lehman IR (1980) RecA protein catalysed strand assimilation: Stimulation by E. coli single stranded DNA binding protein. Proc Natl Acad Sci (USA) 77:857–861
Miller JH (1972) Experiments in Molecular Genetics. Cold Spring Harbor Laboratory, Cold Spring Harbor N. Y.
Mizusawa S, Gottesman S (1983) Protein degradation in E. coli: the lon gene controls the stability of SulA protein. Proc Natl Acad Sci (USA) 80:358–362
Moore PD, Bose KK, Rabkin SD, Strauss BS (1981) Sites of termination of in vitro DNA synthesis on UV and N-acetylamino-fluorene — treated Φx174 templates by pro- and eukaryote DNA polymerases. Proc Natl Acad Sci (USA) 70:110–114
Morand P, Blanco M, Devoret R (1977) Characterisation of lexB mutations of E. coli K12. J Bacteriol 131:572–582
Mount DW (1977) A mutant of E. coli showing constitutive expression of the lysogenic induction and error prone DNA repair pathways. Proc Natl Acad Sci (USA) 78:6236–6240
Mount DW, Low KB, Edmiston SJ (1972) Dominant mutations (lex) in Escherichia coli K12 which affect radiation sensitivity and frequency of ultraviolet light-induced mutations. J Bacteriol 112:886–893
Mount DW, Walker AC, Kosel C (1973) Suppression of lex mutations affecting deoxyribonucleic acid repair in E. coli K12 by closely linked thermosensitive mutations. J Bacteriol 116:950–956
Ogawa T, Pickett GG, Kogoma T, Kornberg A (1984) RNaseH confers specificity in the dnaA-dependent initiation of replication at the unique origin of the E. coli chromosome in vivo and in vitro. Proc Natl Acad Sci (USA) 81:1040–1044
Phizicky EM, Roberts JW (1981) Induction of SOS functions: regulation of proteolytic activity of E. coli RecA protein by interaction with DNA and nucleotide triphosphate. Cell 25:259–267
Pritchard RH (1974) On the growth and form of the bacterial cell. Philos Trans R Soc 267:303–336
Pritchard RH, Lark KG (1964) Induction of replication by thymine starvation at the chromosomal origin in E. coli. J Mol Biol 9:288–307
Rupp WD, Howard-Flanders P (1968) Discontinuities in the DNA synthesised in an excision defective strain of E. coli following UV-irradiation. J Mol Biol 31:291–304
Thomas A, Lloyd RG (1980) Altered regulation of the recA gene in E. coli strains carrying a recA-linked suppressor of lexA. Molec Gen Genet 179:355–358
Trgovcevic Z, Petrovenovic D, Petrovenovic M, Salajsmic E (1980) recA gene product is responsible for inhibition of DNA synthesis after UV irradiation. J Bacteriol 143:1506–1508
Villani G, Boiteux S, Radman M (1978) Mechanisms of ultraviolet induced mutagenesis: Extent and fidelity of in vitro DNA synthesis on irradiated templates. Proc Natl Acad Sci (USA) 78:3037–3041
Walker GC, Dobson PD (1979) Mutagenesis and repair deficiencies of E. coli umuC mutants are suppressed by the plasmid pKM101. Mol Gen Genet 172:17–24
Walker GC (1984) Mutagenesis and inducible responses to deoxyribonucleic acid damage in E. coli. Microbiol Rev 48:60–93
Author information
Authors and Affiliations
Additional information
Communicated by H. Böhme
Rights and permissions
About this article
Cite this article
Khidhir, M.A., Casaregola, S. & Holland, I.B. Mechanism of transient inhibition of DNA synthesis in ultraviolet-irradiated E. coli: Inhibition is independent of recA whilst recovery requires RecA protein itself and an additional, inducible SOS function. Molec Gen Genet 199, 133–140 (1985). https://doi.org/10.1007/BF00327522
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00327522