Selectivity of RNA chain initiation in vitro. 2. Correlation of 5'-triphosphate-labeled oligonucleotides on...

Methods are described for the correlation of 5'-terminal oligonucleotides separated by two-dimensional polyethyleniminecellulose thin-layer chromatogrphy with specific RNA transcripts made in vitro from DNA of phages T7 and lambdacb2. The 5'-terminal oligonucleotides transcribed from DNA containing mutations and alterations which affect the RNA transcripts from specific promoters were compared with fingerprints of RNA from wild type DNA. Specific RNAs were purified on polyacrylamide gels and digested and their 5'-terminal oligonucleotides subjected to chromatography. Transcription of DNA fragments containing specific promoters was carried out and the 5'-oligonucleotide fingerprints of the RNA products compared with fingerprints of the RNA from the whole DNA. Using these methods and information known about T7 and lambdacb2 RNA 5'-terminal sequences, it was possible to identify many of the oligonucleotides separated on the polyethyleniminecellulose chromatography system.