Figure 7. DSB end resection requires the coordinate activities of RecJ, RecQ and SSB proteins.
(A) Functional analysis of the drRecJ α-CT in vivo. Wild-type (WT), recJ mutant (ΔrecJ) and recJ complementary (ΔrecJ/pk-recJ for the entire RecJ and ΔrecJ/pk-recJΔCα for RecJ lacking α-CT) strains were spotted on TGY medium following high-temperature (37 degrees) and MMC treatments. (B) drRecJ processes DNA bearing 3´-ssDNA overhang together with drRecQ and drSSB. The reaction contained drRecJ (5, 10 and 20 nM), drRecQ (100 nM) and drSSB (100 nM). (C) A model for DSB end resection by RecJ, RecQ and SSB proteins in D. radiodurans. RecQ (yellow) is bound to the ss-dsDNA junction, which unwinds them to generate 5´-tailed ssDNA. Following RecJ digestion, the SSB (homodimer, white and grey) is recruited to the resultant 3´-ssDNA overhang, which facilitates further strand exchange reaction.