Optical tweezers were used to track single molecules of two different classes of RNA polymerase as they transcribe DNA into RNA. She shows that RNAP I (which transcribes ribosomal RNA) and RNAP II (which transcribes messenger RNA) both exhibit backtracking dependent pauses and are able to recover from short backtracks via one-dimensional diffusion. Furthermore, they both are able to utilize RNA cleavage reactions to recover from intermediate backtracks. However, the presence of an extra subunit (A12.2) in RNAP I and the association of the cleavage stimulatory factor TFIIS to RNAP II lead to distinct mechanisms to prevent nonrecoverable backtracking.
Optical tweezers were used to track single molecules of two different classes of RNA polymerase as they transcribe DNA into RNA. She shows that RNAP I (which transcribes ribosomal RNA) and RNAP II (which transcribes messenger RNA) both exhibit backtracking dependent pauses and are able to recover from short backtracks via one-dimensional diffusion. Furthermore, they both are able to utilize RNA cleavage reactions to recover from intermediate backtracks. However, the presence of an extra subunit (A12.2) in RNAP I and the association of the cleavage stimulatory factor TFIIS to RNAP II lead to distinct mechanisms to prevent nonrecoverable backtracking.