Stochastic transcription-error correction by backtracking and repelling RNA polymerases

Backtracking of RNA polymerase (RNAP) is an important pausing mechanism during DNA transcription that is part of the error correction process that enhances transcription fidelity. We model the backtracking mechanism of RNA polymerase which usually happens when the polymerase tries to incorporate a mismatched nucleoside triphosphate (NTP). Previous models have made assumptions for easier calculations. One of the key assumptions made is that there is no trailing polymerase behind the backtracking polymerase or the trailing polymerase remains stationary when the leading polymerase backtracks. We derive analytic solutions for a stochastic model that allows for locally interacting RNAPs to explicitly show how a trailing RNAP influences the probability that an error is corrected or incorporated by the leading backtracking RNAP.