The δ subunit in γ complex cross-links primer-template DNA. Protein–DNA complexes formed by UV-induced cross-linking were analyzed by SDS-PAGE. (A) Phosphorimage and (B) Coommassie brilliant blue-stained gel showing cross-linking of γ complex to p/t+1 DNA: lanes 1 and 2 contain p/t+1 alone, loaded onto the gel before and after treatment with DNaseI+S1 nuclease, respectively; lanes 3 and 4 show similar analysis of p/t+1 DNA with γ complex in the reaction; lanes 5 and 6 show p/t+1 with β clamp; lanes 7 and 8 show p/t+1 DNA with γ complex and β. (C) Phosphorimage and (D) Coommassie brilliant blue-stained gel showing similar analysis of p/t+1 cross-linking to γ complex subunits: lanes 1 and 2 show γ, lanes 3 and 4 show γ+β, lanes 5 and 6 show δ, and lanes 7 and 8 show δ+β loaded onto the gel before (lanes 1, 3, 5 and 7) and after (lanes 2, 4, 6 and 8) treatment with nucleases. (E) Phosphorimage and (F) Coommassie brilliant blue-stained gel of a similar analysis as in (C and D), except with δ′ and χ/ψ (−/+β).