AUTHOR=Frimodt-Møller Jakob , Charbon Godefroid , Krogfelt Karen A., Løbner-Olesen Anders 

TITLE=Control regions for chromosome replication are conserved with respect to sequence and location among Escherichia coli strains

JOURNAL=Frontiers in Microbiology

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2015.01011

DOI=10.3389/fmicb.2015.01011

ISSN=1664-302X

ABSTRACT=<p>In <italic>Escherichia coli</italic>, chromosome replication is initiated from <italic>oriC</italic> by the DnaA initiator protein associated with ATP. Three non-coding regions contribute to the activity of DnaA. The <italic>datA</italic> locus is instrumental in conversion of DnaA<sup>ATP</sup> to DnaA<sup>ADP</sup> (<italic>datA</italic> dependent DnaA<sup>ATP</sup> hydrolysis) whereas DnaA rejuvenation sequences 1 and 2 (<italic>DARS1</italic> and <italic>DARS2</italic>) reactivate DnaA<sup>ADP</sup> to DnaA<sup>ATP</sup>. The structural organization of <italic>oriC, datA, DARS1</italic>, and <italic>DARS2</italic> were found conserved among 59 fully sequenced <italic>E. coli</italic> genomes, with differences primarily in the non-functional spacer regions between key protein binding sites. The relative distances from <italic>oriC</italic> to <italic>datA, DARS1</italic>, and <italic>DARS2</italic>, respectively, was also conserved despite of large variations in genome size, suggesting that the gene dosage of either region is important for bacterial growth. Yet all three regions could be deleted alone or in combination without loss of viability. Competition experiments during balanced growth in rich medium and during mouse colonization indicated roles of <italic>datA, DARS1</italic>, and <italic>DARS2</italic> for bacterial fitness although the relative contribution of each region differed between growth conditions. We suggest that this fitness advantage has contributed to conservation of both sequence and chromosomal location for <italic>datA, DARS1</italic>, and <italic>DARS2</italic>.</p>