Figure 2.

Southern blot analysis of end joining products. DSB substrate XM was incubated with HeLa whole cell extract as described in Materials and Methods. After the end joining reaction, substrate DNA was recovered, resolved by 0.8% agarose gel electrophoresis and analyzed by Southern hybridization using random primed M13mp18 as probe as described in Materials and Methods. H, heated-inactivated whole cell extract control; C, complete reaction; T4, reaction containing 0.5 Weiss U T4 ligase in the absence of cell extract. The DSB substrate linear monomer and various product forms are annotated on the left: LM, linear monomer; OCM, open circular monomer; LD, linear dimer; MM, other multimeric forms.