Specific in vitro transcription of 16S rRNA gene by pea chloroplast RNA polymerase.

A highly purified RNA polymerase preparation from pea chloroplasts has been shown to specifically transcribe the 16S rRNA gene in vitro using the recombinant pCB2-8 DNA as a template. The RNA polymerase has been found to show maximum activity and specificity with pea supercoiled rDNA as a template. At low concentrations of ribonucleoside triphosphates, the RNA polymerase selectively initiates transcription on the 16S rRNA gene. A part of the 16S rRNA gene has been sequenced. The mature 16S rRNA has been found by S1 nuclease analysis to contain sequences starting from GAAGCT. The in vitro synthesized RNA has been found to protect the same nucleotides GAAGCT. In addition, the in vitro synthesized RNA was also found to strongly protect bases starting with TATG located at about 260 bases away from the start site of the mature 16S rRNA.