<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sandler, S J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Multiple genetic pathways for restarting DNA replication forks in Escherichia coli K-12.</style></title><secondary-title><style face="normal" font="default" size="100%">Genetics</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Genetics</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Primers</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Replication</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Lethal</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymerase Chain Reaction</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000 Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">155</style></volume><pages><style face="normal" font="default" size="100%">487-97</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In Escherichia coli, the primosome assembly proteins, PriA, PriB, PriC, DnaT, DnaC, DnaB, and DnaG, are thought to help to restart DNA replication forks at recombinational intermediates. Redundant functions between priB and priC and synthetic lethality between priA2::kan and rep3 mutations raise the possibility that there may be multiple pathways for restarting replication forks in vivo. Herein, it is shown that priA2::kan causes synthetic lethality when placed in combination with either Deltarep::kan or priC303:kan. These determinations were made using a nonselective P1 transduction-based viability assay. Two different priA2::kan suppressors (both dnaC alleles) were tested for their ability to rescue the priA-priC and priA-rep double mutant lethality. Only dnaC809,820 (and not dnaC809) could rescue the lethality in each case. Additionally, it was shown that the absence of the 3'-5' helicase activity of both PriA and Rep is not the critical missing function that causes the synthetic lethality in the rep-priA double mutant. One model proposes that replication restart at recombinational intermediates occurs by both PriA-dependent and PriA-independent pathways. The PriA-dependent pathways require at least priA and priB or priC, and the PriA-independent pathway requires at least priC and rep. It is further hypothesized that the dnaC809 suppression of priA2::kan requires priC and rep, whereas dnaC809,820 suppression of priA2::kan does not.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10835375?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Liu, J</style></author><author><style face="normal" font="default" size="100%">Xu, L</style></author><author><style face="normal" font="default" size="100%">Sandler, S J</style></author><author><style face="normal" font="default" size="100%">Marians, K J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Replication fork assembly at recombination intermediates is required for bacterial growth.</style></title><secondary-title><style face="normal" font="default" size="100%">Proc Natl Acad Sci U S A</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Proc. Natl. Acad. Sci. U.S.A.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacteriophage phi X 174</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Polymerase III</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Replication</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Oligodeoxyribonucleotides</style></keyword><keyword><style  face="normal" font="default" size="100%">Open Reading Frames</style></keyword><keyword><style  face="normal" font="default" size="100%">Recombination, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Replication Protein A</style></keyword><keyword><style  face="normal" font="default" size="100%">Templates, Genetic</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1999 Mar 30</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">96</style></volume><pages><style face="normal" font="default" size="100%">3552-5</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">PriA, a 3' --&gt; 5' DNA helicase, directs assembly of a primosome on some bacteriophage and plasmid DNAs. Primosomes are multienzyme replication machines that contribute both the DNA-unwinding and Okazaki fragment-priming functions at the replication fork. The role of PriA in chromosomal replication is unclear. The phenotypes of priA null mutations suggest that the protein participates in replication restart at recombination intermediates. We show here that PriA promotes replication fork assembly at a D loop, an intermediate formed during initiation of homologous recombination. We also show that DnaC810, encoded by a naturally arising intergenic suppressor allele of the priA2::kan mutation, bypasses the need for PriA during replication fork assembly at D loops in vitro. These findings underscore the essentiality of replication fork restart at recombination intermediates under normal growth conditions in bacteria.</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/10097074?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sandler, S J</style></author><author><style face="normal" font="default" size="100%">Satin, L H</style></author><author><style face="normal" font="default" size="100%">Samra, H S</style></author><author><style face="normal" font="default" size="100%">Clark, A J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">recA-like genes from three archaean species with putative protein products similar to Rad51 and Dmc1 proteins of the yeast Saccharomyces cerevisiae.</style></title><secondary-title><style face="normal" font="default" size="100%">Nucleic Acids Res</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Nucleic Acids Res.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Archaea</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Cycle Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Halobacteriaceae</style></keyword><keyword><style  face="normal" font="default" size="100%">Methanococcus</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Molecular</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Phylogeny</style></keyword><keyword><style  face="normal" font="default" size="100%">Rad51 Recombinase</style></keyword><keyword><style  face="normal" font="default" size="100%">Rec A Recombinases</style></keyword><keyword><style  face="normal" font="default" size="100%">Saccharomyces cerevisiae</style></keyword><keyword><style  face="normal" font="default" size="100%">Saccharomyces cerevisiae Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Alignment</style></keyword><keyword><style  face="normal" font="default" size="100%">Sulfolobus</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1996 Jun 1</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">24</style></volume><pages><style face="normal" font="default" size="100%">2125-32</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The process of homologous recombination has been documented in bacterial and eucaryotic organisms. The Escherichia coli RecA and Saccharomyces cerevisiae Rad51 proteins are the archetypal members of two related families of proteins that play a central role in this process. Using the PCR process primed by degenerate oligonucleotides designed to encode regions of the proteins showing the greatest degree of identity, we examined DNA from three organisms of a third phylogenetically divergent group, Archaea, for sequences encoding proteins similar to RecA and Rad51. The archaeans examined were a hyperthermophilic acidophile, Sulfolobus sofataricus (Sso); a halophile, Haloferax volcanii (Hvo); and a hyperthermophilic piezophilic methanogen, Methanococcus jannaschii (Mja). The PCR generated DNA was used to clone a larger genomic DNA fragment containing an open reading frame (orf), that we refer to as the radA gene, for each of the three archaeans. As shown by amino acid sequence alignments, percent amino acid identities and phylogenetic analysis, the putative proteins encoded by all three are related to each other and to both the RecA and Rad51 families of proteins. The putative RadA proteins are more similar to the Rad51 family (approximately 40% identity at the amino acid level) than to the RecA family (approximately 20%). Conserved sequence motifs, putative tertiary structures and phylogenetic analysis implied by the alignment are discussed. The 5' ends of mRNA transcripts to the Sso radA were mapped. The levels of radA mRNA do not increase after treatment with UV irradiation as do recA and RAD51 transcripts in E.coli and S.cerevisiae. Hence it is likely that radA in this organism is a constitutively expressed gene and we discuss possible implications of the lack of UV-inducibility.</style></abstract><issue><style face="normal" font="default" size="100%">11</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/8668545?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sandler, S J</style></author><author><style face="normal" font="default" size="100%">Clark, A J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Mutational analysis of sequences in the recF gene of Escherichia coli K-12 that affect expression.</style></title><secondary-title><style face="normal" font="default" size="100%">J Bacteriol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Bacteriol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Mutational Analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Half-Life</style></keyword><keyword><style  face="normal" font="default" size="100%">Lac Operon</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Biosynthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">Recombinant Fusion Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Regulatory Sequences, Nucleic Acid</style></keyword><keyword><style  face="normal" font="default" size="100%">Ribosomes</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1994</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1994 Jul</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">176</style></volume><pages><style face="normal" font="default" size="100%">4011-6</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The level of translation of recF-lacZ fusions is reduced 20-fold by nucleotides 49 to 146 of recF. In this region of recF, we found a previously described ribosome-interactive sequence called epsilon and a hexapyrimidine tract located just upstream of the epsilon sequence. Mutational studies indicate that the hexapyrimidine sequence is involved in at least some of the reduced translation. When the hexapyrimidine sequence is mutant, mutating epsilon increases the level of translation maximally. We ruled out the possibility that ribosome frameshifting explains most of the effect of these two sequences on expression and suspect that multiple mechanisms may be responsible. In a separate report, we show that mutations in the hexapyrimidine tract and epsilon increase expression of the full-sized recF gene.</style></abstract><issue><style face="normal" font="default" size="100%">13</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/8021183?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sandler, S J</style></author><author><style face="normal" font="default" size="100%">Clark, A J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">RecOR suppression of recF mutant phenotypes in Escherichia coli K-12.</style></title><secondary-title><style face="normal" font="default" size="100%">J Bacteriol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J. Bacteriol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Damage</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Repair</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Epistasis, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Phenotype</style></keyword><keyword><style  face="normal" font="default" size="100%">Plasmids</style></keyword><keyword><style  face="normal" font="default" size="100%">SOS Response (Genetics)</style></keyword><keyword><style  face="normal" font="default" size="100%">Suppression, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Ultraviolet Rays</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1994</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1994 Jun</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">176</style></volume><pages><style face="normal" font="default" size="100%">3661-72</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The recF, recO, and recR genes form the recFOR epistasis group for DNA repair. recF mutants are sensitive to UV irradiation and fail to properly induce the SOS response. Using plasmid derivatives that overexpress combinations of the recO+ and recR+ genes, we tested the hypothesis that high-level expression of recO+ and recR+ (recOR) in vivo will indirectly suppress the recF mutant phenotypes mentioned above. We found that overexpression of just recR+ from the plasmid will partially suppress both phenotypes. Expression of the chromosomal recO+ gene is essential for the recR+ suppression. Hence we call this RecOR suppression of recF mutant phenotypes. RecOR suppression of SOS induction is more efficient with recO+ expression from a plasmid than with recO+ expression from the chromosome. This is not true for RecOR suppression of UV sensitivity (the two are equal). Comparison of RecOR suppression with the suppression caused by recA801 and recA803 shows that RecOR suppression of UV sensitivity is more effective than recA803 suppression and that RecOR suppression of UV sensitivity, like recA801 suppression, requires recJ+. We present a model that explains the data and proposes a function for the recFOR epistasis group in the induction of the SOS response and recombinational DNA repair.</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/8206844?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sandler, S J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Studies on the mechanism of reduction of UV-inducible sulAp expression by recF overexpression in Escherichia coli K-12.</style></title><secondary-title><style face="normal" font="default" size="100%">Mol Gen Genet</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Mol. Gen. Genet.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Primers</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutagenesis, Site-Directed</style></keyword><keyword><style  face="normal" font="default" size="100%">Restriction Mapping</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Messenger</style></keyword><keyword><style  face="normal" font="default" size="100%">SOS Response (Genetics)</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure-Activity Relationship</style></keyword><keyword><style  face="normal" font="default" size="100%">Ultraviolet Rays</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1994</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1994 Dec 15</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">245</style></volume><pages><style face="normal" font="default" size="100%">741-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">UV-inducible sulAp expression, an indicator of the SOS response, is reduced by recF+ overexpression in vivo. Different DNA-damaging agents and amounts of RecO and RecR were tested for their effects on this phenotype. It was found that recF+ overexpression reduced sulAp expression after DNA damage by mitomycin C or nalidixic acid, recO+ and recR+ overexpression partially suppressed the reduction of UV-induced sulAp expression caused by recF+ overexpression. The requirement for ATP binding to RecF to produce the phenotype was tested by genetically altering the putative phosphate binding cleft of recF in a way that should prevent the mutant recF protein from binding ATP. It was found that a change of lysine to glutamine at codon 36 results in a mutant recF protein (RecF4115) that is unable to reduce UV-inducible sulAp expression when overproduced. It is inferred from these results that recF overexpression may reduce UV-inducible sulAp expression by a mechanism that is sensitive to the ability of RecF to bind ATP and to the levels of RecO and RecR (RecOR) in the cell, but not to the type of DNA damage per se. Models are explored that can explain how recF+ overexpression reduces UV induction of sulAp and how RecOR overproduction might suppress this phenotype.</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/7830722?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sandler, S J</style></author><author><style face="normal" font="default" size="100%">Clark, A J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Use of high and low level overexpression plasmids to test mutant alleles of the recF gene of Escherichia coli K-12 for partial activity.</style></title><secondary-title><style face="normal" font="default" size="100%">Genetics</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Genetics</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Alleles</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Chromosomes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Repair</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutagenesis, Site-Directed</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation</style></keyword><keyword><style  face="normal" font="default" size="100%">Phenotype</style></keyword><keyword><style  face="normal" font="default" size="100%">Plasmids</style></keyword><keyword><style  face="normal" font="default" size="100%">Radiation Tolerance</style></keyword><keyword><style  face="normal" font="default" size="100%">Recombination, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Ultraviolet Rays</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1993</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1993 Nov</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">135</style></volume><pages><style face="normal" font="default" size="100%">643-54</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">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.</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/8293970?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sandler, S J</style></author><author><style face="normal" font="default" size="100%">Chackerian, B</style></author><author><style face="normal" font="default" size="100%">Li, J T</style></author><author><style face="normal" font="default" size="100%">Clark, A J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Sequence and complementation analysis of recF genes from Escherichia coli, Salmonella typhimurium, Pseudomonas putida and Bacillus subtilis: evidence for an essential phosphate binding loop.</style></title><secondary-title><style face="normal" font="default" size="100%">Nucleic Acids Res</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Nucleic Acids Res.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacillus subtilis</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Binding Sites</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA-Binding Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Genetic Complementation Test</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Nucleic Acid Conformation</style></keyword><keyword><style  face="normal" font="default" size="100%">Phosphates</style></keyword><keyword><style  face="normal" font="default" size="100%">Pseudomonas putida</style></keyword><keyword><style  face="normal" font="default" size="100%">Salmonella typhimurium</style></keyword><keyword><style  face="normal" font="default" size="100%">Sequence Alignment</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1992</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1992 Feb 25</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">20</style></volume><pages><style face="normal" font="default" size="100%">839-45</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We have compared the recF genes from Escherichia coli K-12, Salmonella typhimurium, Pseudomonas putida, and Bacillus subtilis at the DNA and amino acid sequence levels. To do this we determined the complete nucleotide sequence of the recF gene from Salmonella typhimurium and we completed the nucleotide sequence of recF gene from Pseudomonas putida begun by Fujita et al. (1). We found that the RecF proteins encoded by these two genes contain respectively 92% and 38% amino acid identity with the E. coli RecF protein. Additionally, we have found that the S. typhimurium and P. putida recF genes will complement an E. coli recF mutant, but the recF gene from Bacillus subtilis [showing about 20% identity with E. coli (2)] will not. Amino acid sequence alignment of the four proteins identified four highly conserved regions. Two of these regions are part of a putative phosphate binding loop. In one region (position 36), we changed the lysine codon (which is essential for ATPase, GTPase and kinase activity in other proteins having this phosphate binding loop) to an arginine codon. We then tested this mutation (recF4101) on a multicopy plasmid for its ability to complement a recF chromosomal mutation and on the E. coli chromosome for its effect on sensitivity to UV irradiation. The strain with recF4101 on its chromosome is as sensitive as a null recF mutant strain. The strain with the plasmid-borne mutant allele is however more UV resistant than the null mutant strain. We conclude that lysine-36 and possibly a phosphate binding loop is essential for full recF activity. Lastly we made two chimeric recF genes by exchanging the amino terminal 48 amino acids of the S. typhimurium and E. coli recF genes. Both chimeras could complement E. coli chromosomal recF mutations.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/1542576?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Sandler, S J</style></author><author><style face="normal" font="default" size="100%">Clark, A J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Factors affecting expression of the recF gene of Escherichia coli K-12.</style></title><secondary-title><style face="normal" font="default" size="100%">Gene</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Gene</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Cloning, Molecular</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Sequence Data</style></keyword><keyword><style  face="normal" font="default" size="100%">Peptide Chain Initiation, Translational</style></keyword><keyword><style  face="normal" font="default" size="100%">Recombinant Fusion Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Recombination, Genetic</style></keyword><keyword><style  face="normal" font="default" size="100%">Transcription, Genetic</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1990</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1990 Jan 31</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">86</style></volume><pages><style face="normal" font="default" size="100%">35-43</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">This report describes four factors which affect expression of the recF gene from strong upstream lambda promoters under temperature-sensitive cIAt2-encoded repressor control. The first factor was the long mRNA leader sequence consisting of the Escherichia coli dnaN gene and 95% of the dnaA gene and lambda bet, N (double amber) and 40% of the exo gene. When most of this DNA was deleted, RecF became detectable in maxicells. The second factor was the vector, pBEU28, a runaway replication plasmid. When we substituted pUC118 for pBEU28, RecF became detectable in whole cells by the Coomassie blue staining technique. The third factor was the efficiency of initiation of translation. We used site-directed mutagenesis to change the mRNA leader, ribosome-binding site and the 3 bp before and after the translational start codon. Monitoring the effect of these mutational changes by translational fusion to lacZ, we discovered that the efficiency of initiation of translation was increased 30-fold. Only an estimated two- or threefold increase in accumulated levels of RecF occurred, however. This led us to discover the fourth factor, namely sequences in the recF gene itself. These sequences reduce expression of the recF-lacZ fusion genes 100-fold. The sequences responsible for this decrease in expression occur in four regions in the N-terminal half of recF. Expression is reduced by some sequences at the transcriptional level and by others at the translational level.</style></abstract><issue><style face="normal" font="default" size="100%">1</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/2155860?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Blanar, M A</style></author><author><style face="normal" font="default" size="100%">Sandler, S J</style></author><author><style face="normal" font="default" size="100%">Armengod, M E</style></author><author><style face="normal" font="default" size="100%">Ream, L W</style></author><author><style face="normal" font="default" size="100%">Clark, A J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Molecular analysis of the recF gene of Escherichia coli.</style></title><secondary-title><style face="normal" font="default" size="100%">Proc Natl Acad Sci U S A</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Proc. Natl. Acad. Sci. U.S.A.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Amino Acid Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacterial Proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">Base Sequence</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Repair</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA Replication</style></keyword><keyword><style  face="normal" font="default" size="100%">Escherichia coli</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Weight</style></keyword><keyword><style  face="normal" font="default" size="100%">Mutation</style></keyword><keyword><style  face="normal" font="default" size="100%">Plasmids</style></keyword><keyword><style  face="normal" font="default" size="100%">Recombination, Genetic</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1984</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1984 Aug</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">81</style></volume><pages><style face="normal" font="default" size="100%">4622-6</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We analyzed the nucleotide sequence of a 1.325-kilobase region of wild-type Escherichia coli containing a functional recF gene and six Tn3 mutations that inactivate recF. The analysis shows a potentially translatable reading frame of 1071 nucleotides, which is interrupted by all six insertions. A protein of 40.5 kilodaltons would result from translation of the open reading frame, and a radioactive band of protein of an apparent molecular weight of approximately 40 kilodaltons was seen by the maxicell method using a recF+ plasmid. Putative truncated peptides were seen when two recF::Tn3 mutant plasmids were used. Differential expression of dnaN and recF from a common promoter was noted. recF332::Tn3 was transferred to the chromosome where, in hemizygous condition, it produced UV sensitivity indistinguishable from that produced by two presumed recF point mutations.</style></abstract><issue><style face="normal" font="default" size="100%">15</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/6379647?dopt=Abstract</style></custom1></record></records></xml>