The C-terminal domain of pol II and a DRB-sensitive kinase are required for 3' processing of U2 snRNA.
The human snRNA genes transcribed by RNA polymerase II (e.g. U1 and U2) have a characteristic TATA-less promoter containing an essential proximal sequence element. Formation of the 3' end of these non-polyadenylated RNAs requires a specialized 3' box element whose function is promoter specific. Here we show that truncation of the C-terminal domain (CTD) of RNA polymerase II and treatment of cells with CTD kinase inhibitors, including DRB (5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole), causes a dramatic reduction in proper 3' end formation of U2 transcripts. Activation of 3' box recognition by the phosphorylated CTD would be consistent with the role of phospho-CTD in mRNA processing. CTD kinase inhibitors, however, have little effect on initiation or elongation of transcription of the U2 genes, whereas elongation of transcription of the beta-actin gene is severely affected. This result highlights differences in transcription of snRNA and mRNA genes.
Medlin
Joanne E
JE
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
Uguen
Patricia
P
Taylor
Alice
A
Bentley
David L
DL
Murphy
Shona
S
D004257:DNA Polymerase II / Q000378:metabolism*; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D011494:Protein Kinases / Q000187:drug effects*; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D012342:RNA, Small Nuclear / Q000187:drug effects / Q000378:metabolism*
D004791:Enzyme Inhibitors; D012342:RNA, Small Nuclear; C405484:U2 small nuclear RNA; D004004:Dichlororibofuranosylbenzimidazole; D011494:Protein Kinases; C060137:carboxy-terminal domain kinase; D004257:DNA Polymerase II