Recombination and Replication in DNA Repair of Heavily Irradiated Deinococcus radiodurans
Dea Slade,1 Ariel B. Lindner,1 Gregory Paul,1 and Miroslav Radman1,2,*
1
Universite´ de Paris-Descartes, Faculte´ de Me´ decine, INSERM U571, 156 rue de Vaugirard, 75015 Paris, France
2
Mediterranean Institute for Life Sciences, Mestrovicevo setaliste bb, 21000 Split, Croatia
*Correspondence: This email address is being protected from spambots. You need JavaScript enabled to view it.
DOI 10.1016/j.cell.2009.01.018
SUMMARY
Deinococcus radiodurans’ extreme resistance to
ionizing radiation, desiccation, and DNA-damaging
chemicals involves a robust DNA repair that reas-
sembles its shattered genome. The repair process
requires diploidy and commences with an extensive
exonucleolytic erosion of DNA fragments. Liberated
single-stranded overhangs prime strand elongation
on overlapping fragments and the elongated
complementary strands reestablish chromosomal
contiguity by annealing. We explored the interdepen-
dence of the DNA recombination and replication
processes in the reconstitution of the D. radiodurans
genome disintegrated by ionizing radiation. The
priming of extensive DNA repair synthesis involves
RecA and RadA proteins. DNA polymerase III is
essential for the initiation of repair synthesis,
whereas efficient elongation requires DNA polymer-
ases I and III. Inactivation of both polymerases leads
to degradation of DNA fragments and rapid cell
death. The present in vivo characterization of key
recombination and replication processes dissects
the mechanism of DNA repair in heavily irradiated
D. radiodurans.
