@article {826,
	title = {Effects of mutations involving cell division, recombination, and chromosome dimer resolution on a priA2::kan mutant.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {98},
	year = {2001},
	month = {2001 Jul 17},
	pages = {8203-10},
	abstract = {Recombinational repair of replication forks can occur either to a crossover (XO) or noncrossover (non-XO) depending on Holliday junction resolution. Once the fork is repaired by recombination, PriA is important for restarting these forks in Escherichia coli. PriA mutants are Rec(-) and UV sensitive and have poor viability and 10-fold elevated basal levels of SOS expression. PriA sulB mutant cells and their nucleoids were studied by differential interference contrast and fluorescence microscopy of 4{\textquoteright},6-diamidino-2-phenylindole-stained log phase cells. Two populations of cells were seen. Eighty four percent appeared like wild type, and 16\% of the cells were filamented and had poorly partitioned chromosomes (Par(-)). To probe potential mechanisms leading to the two populations of cells, mutations were added to the priA sulB mutant. Mutating sulA or introducing lexA3 decreased, but did not eliminate filamentation or defects in partitioning. Mutating either recA or recB virtually eliminated the Par(-) phenotype. Filamentation in the recB mutant decreased to 3\%, but increased to 28\% in the recA mutant. The ability to resolve and/or branch migrate Holliday junctions also appeared crucial in the priA mutant because removing either recG or ruvC was lethal. Lastly, it was tested whether the ability to resolve chromosome dimers caused by XOs was important in a priA mutant by mutating dif and the C-terminal portion of ftsK. Mutation of dif showed no change in phenotype whereas ftsK1cat was lethal with priA2kan. A model is proposed where the PriA-independent pathway of replication restart functions at forks that have been repaired to non-XOs.},
	keywords = {Adenosine Triphosphatases, Bacterial Proteins, Cell Division, Chromosomes, Bacterial, Dimerization, DNA Helicases, Endodeoxyribonucleases, Escherichia coli, Escherichia coli Proteins, Exodeoxyribonuclease V, Exodeoxyribonucleases, Gene Expression, Membrane Proteins, Mutagenesis, Rec A Recombinases, Recombination, Genetic, SOS Response (Genetics)},
	issn = {0027-8424},
	doi = {10.1073/pnas.121007698},
	author = {McCool, J D and Sandler, S J}
}
@article {828,
	title = {The importance of repairing stalled replication forks.},
	journal = {Nature},
	volume = {404},
	year = {2000},
	month = {2000 Mar 2},
	pages = {37-41},
	abstract = {The bacterial SOS response to unusual levels of DNA damage has been recognized and studied for several decades. Pathways for re-establishing inactivated replication forks under normal growth conditions have received far less attention. In bacteria growing aerobically in the absence of SOS-inducing conditions, many replication forks encounter DNA damage, leading to inactivation. The pathways for fork reactivation involve the homologous recombination systems, are nonmutagenic, and integrate almost every aspect of DNA metabolism. On a frequency-of-use basis, these pathways represent the main function of bacterial DNA recombination systems, as well as the main function of a number of other enzymatic systems that are associated with replication and site-specific recombination.},
	keywords = {Bacteria, Bacterial Proteins, Chromosomes, Bacterial, DNA Replication, DNA, Bacterial, Escherichia coli, Recombination, Genetic, Replication Origin, SOS Response (Genetics)},
	issn = {0028-0836},
	doi = {10.1038/35003501},
	author = {Cox, M M and Goodman, M F and Kreuzer, K N and Sherratt, D J and Sandler, S J and Marians, K J}
}
@article {836,
	title = {Differential suppression of priA2::kan phenotypes in Escherichia coli K-12 by mutations in priA, lexA, and dnaC.},
	journal = {Genetics},
	volume = {143},
	year = {1996},
	month = {1996 May},
	pages = {5-13},
	abstract = {First identified as an essential component of the phi X174 in vitro DNA replication system, PriA has ATPase, helicase, translocase, and primosome-assembly activities. priA1::kan strains of Escherichia coli are sensitive to UV irradiation, deficient in homologous recombination following transduction, and filamentous. priA2::kan strains have eightfold higher levels of uninduced SOS expression than wild type. We show that (1) priA1::kan strains have eightfold higher levels of uninduced SOS expression, (2) priA2::kan strains are UVS and Rec-, (3) lexA3 suppresses the high basal levels of SOS expression of a priA2::kan strain, and (4) plasmid-encoded priA300 (K230R), a mutant allele retaining only the primosome-assembly activity of priA+, restores both UVR and Rec+ phenotypes to a priA2::kan strain. Finally, we have isolated 17 independent UVR Rec+ revertants of priA2::kan strains that carry extragenic suppressors. All 17 map in the C-terminal half of the dnaC gene. DnaC loads the DnaB helicase onto DNA as a prelude for primosome assembly and DNA replication. We conclude that priA{\textquoteright}s primosome-assembly activity is essential for DNA repair and recombination and that the dnaC suppressor mutations allow these processes to occur in the absence of priA.},
	keywords = {Bacterial Proteins, Bacteriophage phi X 174, beta-Galactosidase, Chromosomes, Bacterial, DNA Helicases, DNA Replication, DNA-Binding Proteins, Dose-Response Relationship, Radiation, Escherichia coli, Escherichia coli Proteins, Genes, Bacterial, Genetic Markers, Mutagenesis, Phenotype, Recombination, Genetic, Replication Protein A, Repressor Proteins, Serine Endopeptidases, Suppression, Genetic, Transduction, Genetic, Ultraviolet Rays},
	issn = {0016-6731},
	author = {Sandler, S J and Samra, H S and Clark, A J}
}
@article {843,
	title = {Use of high and low level overexpression plasmids to test mutant alleles of the recF gene of Escherichia coli K-12 for partial activity.},
	journal = {Genetics},
	volume = {135},
	year = {1993},
	month = {1993 Nov},
	pages = {643-54},
	abstract = {We showed that sufficient overexpression of the wild-type recF gene interfered with three normal cell functions: (1) UV induction of transcription from the LexA-protein-repressed sulA promoter, (2) UV resistance and (3) cell viability at 42 degrees. To show this, we altered a low-level overexpressing recF+ plasmid with a set of structurally neutral mutations that increased the rate of expression of recF. The resulting high-level overexpressing plasmid interfered with UV induction of the sulA promoter, as did the low-level overexpressing plasmid. It also reduced UV resistance more than its low level progenitor and decreased viability at 42 degrees, an effect not seen with the low-level plasmid. We used the high-level plasmid to test four recF structural mutations for residual activity. The structural alleles consisted of an insertion mutation, two single amino acid substitution mutations and a double amino acid substitution mutation. On the Escherichia coli chromosome the three substitution mutations acted similarly to a recF deletion in reducing UV resistance in a recB21 recC22 sbcB15 sbcC201 genetic background. By this test, therefore, all three appeared to be null alleles. Measurements of conjugational recombination revealed, however, that the three substitution mutations may have residual activity. On the high-level overexpressing plasmid all three substitution mutations definitely showed partial activity. By contrast, the insertion mutation on the high-level overexpressing plasmid showed no partial activity and can be considered a true null mutation. One of the substitutions, recF143, showed a property attributable to a leaky mutation. Another substitution, recF4101, may block selectively two of the three interference phenotypes, thus allowing us to infer a mechanism for them.},
	keywords = {Alleles, Bacterial Proteins, Base Sequence, Chromosomes, Bacterial, DNA Repair, DNA, Bacterial, DNA-Binding Proteins, Escherichia coli, Escherichia coli Proteins, Gene Expression, Genes, Bacterial, Molecular Sequence Data, Mutagenesis, Site-Directed, Mutation, Phenotype, Plasmids, Radiation Tolerance, Recombination, Genetic, Ultraviolet Rays},
	issn = {0016-6731},
	author = {Sandler, S J and Clark, A J}
}
