Effect of EcoSSB on the state of the DNA template and the RNA
product. (A and B) Transcription reactions contained 5 nM
unlabeled 12-P2–52 DNA template and [α-32P]UTP.
(C and D) Transcription reactions contained 5 nM 5′
32P-labeled template and unlabeled NTPs. Where indicated,
EcoSSB was present at 1 μM. After a 15-min incubation, each
mixture was divided into three aliquots and treated for 15 min at 37°C
with no additions, RNase H, or Nuclease S1, as indicated, and analyzed by
native PAGE.