Fig. 1. DNA ds-break repair pathway (Friedberg et al., 1995) and HU binding to the repair intermediates. HU protein at concentrations indicated in nM was mixed with labeled DNA in a buffer containing 200 mM NaCl, and free and bound DNA were gel-separated in 90 mM Tris–borate/EDTA buffer. (A) ds-DNA; (B) 5′-overhang; (C) 3′-overhang; (D) incomplete junction; (E) 3′-invasion; (F) junction; (G) nick.