TY - JOUR
T1 - Fuse or die: how to survive the loss of Dam in Vibrio cholerae
AU - Val, Marie-Eve
AU - Kennedy, Sean P
AU - Soler-Bistue, Alfonso J.
AU - Barbe, Valérie
AU - Bouchier, Christiane
AU - Ducos-Galand, Magaly
AU - Skovgaard, Ole
AU - Mazel, Didier
PY - 2014/2
Y1 - 2014/2
N2 - Dam methylates GATC sequences in γ-proteobacteria genomes, regulating several cellular functions including replication. In Vibrio cholerae, which has two chromosomes, Dam is essential for viability, owing to its role in chr2 replication initiation. In this study, we isolated spontaneous mutants of V. cholerae that were able to survive the deletion of dam. In these mutants, homologous recombination and chromosome dimer resolution are essential, unless DNA mismatch repair is inactivated. Furthermore, the initiator of chr2 replication, RctB, is no longer required. We show that, instead, replication of chr2 is insured by spontaneous fusion with chr1 and piggybacking its replication machinery. We report that natural fusion of chr1 and chr2 occurred by two distinct recombination pathways: homologous recombination between repeated IS elements and site-specific recombination between dif sites. Lastly, we observed a preferential fusion of the two chromosomes in their terminus of replication
AB - Dam methylates GATC sequences in γ-proteobacteria genomes, regulating several cellular functions including replication. In Vibrio cholerae, which has two chromosomes, Dam is essential for viability, owing to its role in chr2 replication initiation. In this study, we isolated spontaneous mutants of V. cholerae that were able to survive the deletion of dam. In these mutants, homologous recombination and chromosome dimer resolution are essential, unless DNA mismatch repair is inactivated. Furthermore, the initiator of chr2 replication, RctB, is no longer required. We show that, instead, replication of chr2 is insured by spontaneous fusion with chr1 and piggybacking its replication machinery. We report that natural fusion of chr1 and chr2 occurred by two distinct recombination pathways: homologous recombination between repeated IS elements and site-specific recombination between dif sites. Lastly, we observed a preferential fusion of the two chromosomes in their terminus of replication
U2 - 10.1111/mmi.12483
DO - 10.1111/mmi.12483
M3 - Journal article
VL - 91
SP - 665
EP - 678
JO - Molecular Microbiology
JF - Molecular Microbiology
SN - 0950-382X
IS - 4
ER -