Figure 4.

Products of R-loop processing by gel analysis. R-loop templates were formed by in vitro transcription; the DNA control template was not transcribed, while the other templates were transcribed and treated with RNase A to remove single-stranded RNA but retain the R-loop configuration as indicated schematically above each gel. These templates were treated with HeLa cell extract. Products of HeLa extract processing were extracted, treated with RNase A+H to remove residual R-loops and transformed into E. coli. Following minimal culturing, products of each R-loop configuration were resolved on polyacrylamide gels alongside known size markers. The product immediately adjacent to the ladder lane in each gel (indicated by arrow) is the untranscribed, unprocessed parental DNA template that serves as a size marker containing 79 (CAG)·(CTG) repeats.