FIG 2 .
SML RNA present in phSP6-ProPol stocks. A crude phSP6-ProPol preparation (108 PFU) was either left untreated or treated with MRI to a final concentration of 1 U/μl. Either 5 ng (++) or 1 ng (+) RNase A was then added, and the mixture was incubated for 30 min at 37°C. After purification of RNA and digestion with DNase I, reverse transcription was carried out using the DnSt primer. After reverse transcription but prior to PCR, cDNA from each sample was diluted 1:10 to estimate a 10-fold signal reduction. The primers DnSt and UpSt were then used to amplify a 150-bp section of SML cDNA using PCR. Products were separated on a 2% agarose gel and visualized by ethidium bromide staining. The locations of DNA size markers are indicated.