Image removed for copyright considerations Figure 2 in Muratani M, Tansey WP. "How the ubiquitin-proteasome system controls transcription Nat Rev Mol Cell Biol. 2003 Mar; 4(3): 192-201 Regulation of tcr by ubiquitylation of rna polymerase II. Transcription-coupled repair (tcr)is the mechanism through which mutations in actively transcribed genes are preferentially repaired Elongating RNa polymerase Ii (pol II, which has a unique pattern of phosphorylation on its carboxy-terminal domain(CTD), encounters a damaged DNA segment. The stalled polymerase(b then recruits the ubiquitin(Ub)-ligase Rsp5(c),which in turn ubiquitylates the largest subunit of pol Ii in a CTD-phosphorylation-dependent manner. d I Ubiquity lation is followed by the proteasomal destruction of at least one subunit of polymerase, recruitment of the repair machinery and restoration of DNa integrityImage removed for copyright considerations. Figure 2 in Muratani M, Tansey WP. "How the ubiquitin-proteasome system controls transcription." Nat Rev Mol Cell Biol. 2003 Mar;4(3):192-201. Regulation of TCR by ubiquitylation of RNA polymerase II. Transcription-coupled repair (TCR) is the mechanism through which mutations in actively transcribed genes are preferentially repaired. a | Elongating RNA polymerase II (pol II), which has a unique pattern of phosphorylation on its carboxy-terminal domain (CTD), encounters a damaged DNA segment. The stalled polymerase (b) then recruits the ubiquitin (Ub)-ligase Rsp5 (c), which in turn ubiquitylates the largest subunit of pol II in a CTD-phosphorylation-dependent manner. d | Ubiquitylation is followed by the proteasomal destruction of at least one subunit of polymerase, recruitment of the repair machinery and restoration of DNA integrity