A 10 residue motif at the C-terminus of the RNA pol II CTD is required for transcription, splicing and 3' end processing.
Fong N, Bird G, Vigneron M, Bentley DL. A 10 residue motif at the C-terminus of the RNA pol II CTD is required for transcription, splicing and 3' end processing. EMBO J. 2003 Aug 15; 22(16):4274-82.