This figure shows the distributions of cells with different levels of constitutive SOS expression (detected as GFP fluorescence) expressed as the percentage of cells in the population.

<p>The graphs truncate the percentage of cells at 25%. The strains are in order from top of the graph to the bottom with the relevant part of the genotype in parentheses. Unless otherwise indicated, all strains were grown in minimal medium at 37°C with aeration. The strains are: SS1408 (<i>lexA51::Tn5</i>), SS4629 (<i>recA730</i>), SS4976 (<i>recAo1403 recA4142</i>), SS6013 (<i>recA4142</i>), SS6088 (<i>recAo1403 recA⁺</i>) and SS996 (<i>recA</i>⁺).</p

Same as for Figure 2.

<p>SS4976 (<i>recAo1403 recA4142</i>), SS5312 (<i>recAo1403 recA4142 del(recX)</i>) SS6023 (<i>recAo1403 recA4142 del(recBCD)::cat</i>), SS6048 (<i>recAo1403 recA4142 del(recBCD)::cat del(recX)</i>), SS4696 (<i>recAo1403 recA4142 recF4115</i>), SS5394 (<i>recAo1403 recA4142 recF4115 del(recX)</i>).</p

Same as for Figure 2.

<p>All grown in rich medium: SS996 (<i>recA</i>⁺), SS6080 (<i>del(recX)</i>), SS6013 (<i>recA4142</i>), SS6019 (<i>recA4142 del(recX)</i>), SS4976 (<i>recAo1403 recA4142</i>), SS5312 (<i>recAo1403 recA4142 del(recX)</i>).</p

Same as for Figure 2.

<p>SS4629 (<i>recA730</i>), SS6044 (<i>recA730 del(recBCD)::cat</i>), SS4645 (<i>recA730 recF4115</i>), SS5316 (<i>recA730 del(dinI)</i>), SS4976 (<i>recAo1403 recA4142</i>), SS6023 (<i>recAo1403 recA4142 del(recBCD)::cat</i>), SS4696 (<i>recAo1403 recA4142 recF4115</i>), SS5315 (<i>recAo1403 recA4142 del(dinI)</i>).</p

Summary of phenotypic analysis of <i>recA</i> mutants used in this study.

a<p>ND is Not Determined because the cells are already fully induced for SOS expression.</p

Strains used in this work.

a<p>JC13509 has the following genotype: <i>sulB103 lacMS286 φ 80dIIlacBK1 argE3 hi-4 thi-1 xyl-5 mtl-1 rpsL31 tsx</i>. The <i>lacMS286φ80dIIlacBK1</i> code for two partial non-overlapping deletions of the <i>lac</i> operon <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004100#pone.0004100-Konrad1" target="_blank">[73]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004100#pone.0004100-Zieg1" target="_blank">[74]</a>.</p>b<p>Select for Kan^R and then screen for other marker phenotypically or by PCR.</p>c<p>Select for Tet^R and then screen for other marker phenotypically or by PCR.</p>d<p>Select for Cat^R and then screen for other marker phenotypically or by PCR.</p>e<p>Select for Amp^R.</p>f<p>Select for AlaS⁺.</p>g<p>This deletion allele was created by first transducing the kan resistant derivative from the Kieo collection into the strain as indicated in the reference column. pLH29, carrying the <i>flp</i> gene, was then introduced and Kan sensitive derivatives were screened (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004100#pone.0004100-Huang1" target="_blank">[75]</a>.</p>h<p><i>recX::cat</i> was amplified with prSJS748,749 using pACYC184 (New England Biolabs) as a template. <i>recX::cat</i> was transferred to the chromosome using the <i>exo-bet</i> method <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004100#pone.0004100-Datsenko1" target="_blank">[76]</a> next to the <i>recA</i> allele indicated. This original combination of mutants were named and saved as the strain indicated as the donor in this cross.</p>i<p>These <i>recAo</i> or <i>recA</i> mutations were first constructed on a plasmid as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004100#s4" target="_blank">Materials and Methods</a>. They were then transferred to the chromosome using the method of Datsenko and Wanner <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004100#pone.0004100-Datsenko1" target="_blank">[76]</a> using a strain that was <i>lexA3 malE::Tn10</i> in a JC13509 background with pKD46 encoding <i>exo</i> and <i>bet</i>. This original combination of mutants were named and saved as the strain indicated as the donor in this cross.</p>j<p>Full notation for <i>ygaD</i> mutation is <i>ygaD1::kan</i> .Full notation for <i>recX</i> mutation is <i>del(recX)4166::cat</i>. Full notation for <i>recBCD</i> mutation is <i>del(recBCD)::cat</i>. Full notation for Ω<i>gfp</i> mutation is <i>Δattλ::sulApΩgfp-mut2</i>.</p

Oligonucleotide primers used in this work.

<p>Oligonucleotide primers used in this work.</p

Same as for Figure 2.

<p>SS6013 (<i>recA4142</i>) minimal, SS6013 (<i>recA4142</i>) rich, SS4976 (<i>recAo1403 recA4142</i>) minimal, SS4976 (<i>recAo1403 recA4142</i>) rich.</p