Characterization of T7-specific Ribonucleic Acid Polymerase IV. RESOLUTION OF THE MAJOR IN VITRO TRANSCRIPTS BY GEL ELECTROPHORESIS

摘要: Abstract The major in vitro RNA transcripts synthesized by T7 polymerase with and T3 DNA templates have been resolved electrophoresis on polyacrylamide gels. Six discrete size classes of RNAs are found, designated I to VI. apparent molecular weights, estimated from their electrophoretic mobilities, span a broad range, 2 x 105 5 106. At least two minor species, weights greater than 106, also detected. six species approximately equimolar amounts, the exception III, which is made about twice this amount. It likely that III mixture ("IIIa" "IIIb") transcribed separate regions genome. Hence, tentatively identified seven late transcription units phage chromosome, read equal efficiences. (or seven) products initiated independently guanosine triphosphate at 5' terminus, elongated rate 230 nucleotides per s under standard conditions. When used transcribe DNA, single transcript weight similar III. This suggests an explanation for reduced synthesis vitro, implies promoter sites heterogeneous nature.