FIG. 4.

HMG2 inhibits nicking at sites distant from the hairpin tip. (A) Synthetic 5′-end-labeled hairpins were incubated with RAG proteins in the presence or absence of HMG2, or with HMG2 alone, as indicated above the lanes. Reactions were carried out for 3 or 2 h with coexpressed GST- or MH-RAGs, respectively. Reactions in both panels were performed in 1 mM Mn²⁺ and analyzed as for Fig. 1A; in each, the 58-nt fragment derived from nicking 5 nt 5′ of the hairpin tip is indicated with an arrow. (B) RAG proteins were preincubated with or without HMG2 for 15 min at 30°C before addition of hairpin substrate, and samples were analyzed at the indicated times.