Parameters affecting the elongation block by RNA polymerase II at the SV40 attenuator 1 in vitro

We have previously suggested that folding of the SV40 attenuator RNA 1 into two hairpin elements leads to a block of transcription elongation. Using site-directed mutagenesis, we created three templates that either strengthened or weakened the proposed hairpin structures. The mutated and wildtype templates were cloned downstream from the adenovirus 2 MLP, and transcription patterns were compared among the templates, in cell-free extracts