engleski

DNA repair in Deinococcus radiodurans: from hundreds of fragments to the functional chromosomes

Bacterium Deinococcus radiodurans is one of the most radiation resistant organisms known. It can sustain extreme levels of ionizing radiation breaking its genome into hundreds of shorts fragments. Remarkably, in just couple of hours, these fragments are reassembled into functional chromosomes due to an efficient and precise DNA repair process. We found that this repair involves a special kind of “ extended synthesis-dependent strand annealing” (ESDSA) followed and completed by crossovers. In ESDSA, chromosomal fragments produced by radiation are used both as primers and templates for a massive synthesis of long single-strand extensions which then anneal thereby accurately connecting contiguous DNA fragments into long linear intermediates. These intermediates are finally matured by RecA-dependent homologous recombination into functional circular chromosomes that are patchworks of old (synthesized before radiation) and new (synthesized after radiation) double-stranded DNA blocks.

Deinococcus radiodurans; DNA repair; DNA synthesis; homologous recombination

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