Figure 4.

Detection of G4 DNA formation by transcription stop assay. DNA templates were transcribed in vitro such that the transcripts were radioactively labeled. Elongation was allowed to proceed for 30 min at 37°C after addition of NTPs to the reaction, followed by RNA purification and separation on 12% denaturing polyacrylamide gels. A schematic representation of transcription substrates c-myc-A12 and c-myc-A12-cy3-cy5 and the expected sizes of the transcripts resulting from arrest at myc1245 (30–31 nt RNA), Cy3 (39 nt RNA), Cy5 (57 nt RNA) in addition to the Runoff RNA (74 nt RO RNA) are shown to the right of the gel picture.