Transcription reinitiation by recycling RNA polymerase that diffuses on DNA after releasing terminated RNA

Authors: Wooyoung Kang, Kook Sun Ha, Heesoo Uhm, Kyuhyong Park, Ja Yil Lee, Sungchul Hohng, Changwon Kang

유전자 발현 첫 과정에서 DNA의 특정 구간에 맞추어 RNA가 합성되는데, DNA가 보유하고 있는 유전정보를 RNA에 그대로 옮겨 적기 때문에 전사(transcription)이라고 한다. 지금까지는 이 전사 과정이 개시-연장-종결의 세 단계로 알려져 있었다. 그러나 이번 연구를 통해 RNA가 방출되는 종결단계에 이어서 RNA 중합효소가 DNA에 남아서 이동하는 4번째 단계가 있다는 것이 새로이 밝혀졌고, 이를 재생(recycling) 단계라고 명명하였다. 또한 재생하는 RNA 중합효소가 DNA 위에서 종결위치로부터 개시위치로 옮겨 전사를 다시 시작하는 것을 재개시(reinitiation)라고 명명하였다. 이 발견으로 전사 과정의 ‘재생’ 과 ‘재개시’가 새롭게 추가 되었다.

Abstract

Despite extensive studies on transcription mechanisms, it is unknown how termination complexes are disassembled, especially in what order the essential components dissociate. Our single-molecule fluorescence study unveils that RNA transcript release precedes RNA polymerase (RNAP) dissociation from the DNA template much more often than their concurrent dissociations in intrinsic termination of bacterial transcription. As termination is defined by the release of product RNA from the transcription complex, the subsequent retention of RNAP on DNA constitutes a previously unidentified stage, termed here as recycling. During the recycling stage, post-terminational RNAPs one-dimensionally diffuse on DNA in downward and upward directions, and can initiate transcription again at the original and nearby promoters in the case of retaining a sigma factor. The efficiency of this event, termed here as reinitiation, increases with supplement of a sigma factor. In summary, after releasing RNA product at intrinsic termination, recycling RNAP diffuses on the DNA template for reinitiation most of the time.

링크 : https://www.nature.com/articles/s41467-019-14200-3