Fig. 4.

NusA-mediated transcription-coupled translesion DNA synthesis (TC-TLS, left) and transcription-coupled DNA repair (TC-NER, right). During TC-TLS, NusA, bound to RNAP recruits the Y-family DNA polymerase DinB to gaps in the DNA opposite from lesions (grey oval) in the non-transcribed strand [104]. This results in filling of the gap (interrupted line) via the action of DinB. During TC-NER, RNAP-bound NusA recruits the UvrAB complex to sites of DNA damage (grey oval), such as nitrofurazone adducts, which do not enter the active site of RNAP. The recruitment of NER machinery via the NusA-UvrA interaction has been proposed to result in excision of the damage and preferential repair of the transcribed strand [100]