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Rec-a-independent recombination between tandemly repeated sequences in escherichia coli

Objective



Research objectives and content
The main objective of this work is to understand the processes that may influence the stability of long repeated sequences in the genome of micro-organisms. Previous results showed that, in E. coli recombination between .andemly repeated sequences is independent of RecA and of other homlogous recombination functions. However, two pathways can be activated by mutations that stimulate recombination. One is RecA-independent, and is activated by a mutation in the polymerase III gene. Another is RecA-dependent and is activated by a mutation in the uvrD gene. Both pathways will be studied here.To characterise the role of polymerase III in recombination, different polymerase mutants will be tested searching specifically for a possible correlation between the mutator and deletion-prone properties of the polymerases. To analyse the reasons for the hyper-recombination phenotype of uvrD mutants, we will test whether this phenotype is correlated with the defect in the repair of lesions and/or the repair of mismatches In addition, new hyper-recombination mutants isolated in the laboratory will be characterised They may reveal new pathways of tandem repeat recombination or improve our understanding of the two known pathways. The characterisation of functions that stimulate recombination may help to define strains i which the stability of the repeated sequences is increased.
Training content (objective, benefit and expected impact)
Learning of bacterial genetic of repair, replication and recombination while understanding the process that control stability of repeated sequences can be of particular importance both in the context of biotechnology and for fundamental knowledge. This work combines the use of molecular biology and E coli classical genetics for recombination studies. It should complete my training on genetic concepts and approaches to study DNA metabolism.
Links with industry / industrial relevance (22)

Coordinator

Institut National de la Recherche Agronomique
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78352 Jouy-en-josas
France