To confirm the transcription-coupled nature of UV damage repair in this system, we treated cells with a transcription inhibitor (flavopiridol, FLV) and we also knocked down the core TCR factor Excision repair cross-complementation group 6 (ERCC6, also known as Cockayne Syndrome B, CSB), both resulting in a marked inhibition of repair synthesis (Fig. 2b, c). Here, ERCC6 is linked to Cockayne syndrome.