Figure 2.

(A) Diagram of the cis-acting sequences required for viral DNA cleavage/packaging. (Upper) One possible arrangement of an HSV-1 concatemer (as described in the introduction). (Lower) A detailed representation of the junction between two linear genomes and the sequences required for DNA cleavage/packaging. (B) EMSA analysis of the interaction between U_L28 protein and DNA bearing pac sequences. DNA fragments spanning the regions U_c-DR1-U_b (lanes 1–4), U_c-DR1 (lanes 5–8), or DR1-U_b (lanes 9–12) were radiolabeled and either stored at −20°C [yielding the double-stranded (ds) probes present in lanes 1–2, 5–6, and 9–10] or boiled for 3 min and quickly transferred to ice before storage (probes labeled d/r, for denatured and reannealed; lanes 3–4, 7–8, and 11–12). The resultant DNA species were incubated at 5 nM in the absence or presence of U_L28 protein (50 nM), and complexes were analyzed by EMSA. An arrow denotes the position at which the U_L28 protein-DNA complexes migrate.