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Fast growth conditions uncouple the final stages of chromosome segregation and cell division in Escherichia coli.
Galli, Elisa; Midonet, Caroline; Paly, Evelyne; Barre, François-Xavier.
Afiliación
  • Galli E; Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, Gif sur Yvette, France.
  • Midonet C; Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, Gif sur Yvette, France.
  • Paly E; Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, Gif sur Yvette, France.
  • Barre FX; Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris Sud, Gif sur Yvette, France.
PLoS Genet ; 13(3): e1006702, 2017 03.
Article en En | MEDLINE | ID: mdl-28358835
ABSTRACT
Homologous recombination between the circular chromosomes of bacteria can generate chromosome dimers. They are resolved by a recombination event at a specific site in the replication terminus of chromosomes, dif, by dedicated tyrosine recombinases. The reaction is under the control of a cell division protein, FtsK, which assembles into active DNA pumps at mid-cell during septum formation. Previous studies suggested that activation of Xer recombination at dif was restricted to chromosome dimers in Escherichia coli but not in Vibrio cholerae, suggesting that FtsK mainly acted on chromosome dimers in E. coli but frequently processed monomeric chromosomes in V. cholerae. However, recent microscopic studies suggested that E. coli FtsK served to release the MatP-mediated cohesion and/or cell division apparatus-interaction of sister copies of the dif region independently of chromosome dimer formation. Here, we show that these apparently paradoxical observations are not linked to any difference in the dimer resolution machineries of E. coli and V. cholerae but to differences in the timing of segregation of their chromosomes. V. cholerae harbours two circular chromosomes, chr1 and chr2. We found that whatever the growth conditions, sister copies of the V. cholerae chr1 dif region remain together at mid-cell until the onset of constriction, which permits their processing by FtsK and the activation of dif-recombination. Likewise, sister copies of the dif region of the E. coli chromosome only separate after the onset of constriction in slow growth conditions. However, under fast growth conditions the dif sites separate before constriction, which restricts XerCD-dif activity to resolving chromosome dimers.
Asunto(s)

Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Cromosomas Bacterianos / Proteínas de Escherichia coli / Escherichia coli / Recombinación Homóloga / Proteínas de la Membrana Idioma: En Revista: PLoS Genet Asunto de la revista: GENETICA Año: 2017 Tipo del documento: Article País de afiliación: Francia

Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Cromosomas Bacterianos / Proteínas de Escherichia coli / Escherichia coli / Recombinación Homóloga / Proteínas de la Membrana Idioma: En Revista: PLoS Genet Asunto de la revista: GENETICA Año: 2017 Tipo del documento: Article País de afiliación: Francia