Role of the C-terminal domain of RNA polymerase II in expression of small nuclear RNA genes.
Pol II (RNA polymerase II) transcribes the genes encoding proteins and non-coding snRNAs (small nuclear RNAs). The largest subunit of Pol II contains a distinctive CTD (C-terminal domain) comprising a repetitive heptad amino acid sequence, Tyr(1)-Ser(2)-Pro(3)-Thr(4)-Ser(5)-Pro(6)-Ser(7). This domain is now known to play a major role in the processes of transcription and co-transcriptional RNA processing in expression of both snRNA and protein-coding genes. The heptapeptide repeat unit can be extensively modified in vivo and covalent modifications of the CTD during the transcription cycle result in the ordered recruitment of RNA-processing factors. The most studied modifications are the phosphorylation of the serine residues in position 2 and 5 (Ser(2) and Ser(5)), which play an important role in the co-transcriptional processing of both mRNA and snRNA. An additional, recently identified CTD modification, phosphorylation of the serine residue in position 7 (Ser(7)) of the heptapeptide, is however specifically required for expression of snRNA genes. These findings provide interesting insights into the control of gene-specific Pol II function.
Egloff
Sylvain
S
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK. sylvain.egloff@path.ox.ac.uk
Murphy
Shona
S
D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D008954:Models, Biological; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000737:chemistry* / Q000378:metabolism*; D012342:RNA, Small Nuclear / Q000235:genetics*; D013329:Structure-Activity Relationship; D014158:Transcription, Genetic
D012342:RNA, Small Nuclear; D010768:Phosphoserine; D012319:RNA Polymerase II