Figure 3. HARP disassembles bidirectional replication bubbles containing an RNA:DNA hybrid.

(A) hsHARP and dmHARP can disassemble a bidirectional replication bubble. Top: A 90 bp, centrally located, replication bubble was formed with oligonucleotides B90 (5′-³²P-labeled) and T90 pre-annealed to 290 nt bottom (BS) and top (TS) strands, respectively. Variants of TS with 1 or 2 bp mismatches relative to the BS at both ends of the 90 bp bubble were also used. Bottom: The presence and source of HARP (1x is 20 nM), bp mismatches in the TS, and the presence of UTP or ATP are indicated above the gel image. The replication bubble, non-annealed B90:BS and the B90:T90 branch migration products are identified at the left. (B) hsHARP and dmHARP (at 20 nM) can disassemble a replication bubble containing an RNA:DNA hybrid. Annotation follows (A).