Activation of RNA polymerase III transcription in cells transformed by simian virus 40.
RNA polymerase (Pol) III transcription is abnormally active in fibroblasts that have been transformed by simian virus 40 (SV40). This report presents evidence that two separate components of the general Pol III transcription apparatus, TFIIIB and TFIIIC2, are deregulated following SV40 transformation. TFIIIC2 subunits are expressed at abnormally high levels in SV40-transformed cells, an effect which is observed at both protein and mRNA levels. In untransformed fibroblasts, TFIIIB is subject to repression through association with the retinoblastoma protein RB. The interaction between RB and TFIIIB is compromised following SV40 transformation. Furthermore, the large T antigen of SV40 is shown to relieve repression by RB. The E7 oncoprotein of human papillomavirus can also activate Pol III transcription, an effect that is dependent on its ability to bind to RB. The data provide evidence that both TFIIIB and TFIIIC2 are targets for activation by DNA tumor viruses.
Larminie
C G
CG
Institute of Biomedical and Life Sciences, Division of Biochemistry and Molecular Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
Sutcliffe
J E
JE
Tosh
K
K
Winter
A G
AG
Felton-Edkins
Z A
ZA
White
R J
RJ
D016475:3T3 Cells; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000378:metabolism; D002457:Cell Extracts; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral; D004789:Enzyme Activation; D015870:Gene Expression; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism; D027383:Papillomaviridae; D050725:Papillomavirus E7 Proteins; D012320:RNA Polymerase III / Q000378:metabolism*; D012333:RNA, Messenger; D016160:Retinoblastoma Protein / Q000378:metabolism; D013539:Simian virus 40 / Q000502:physiology*; D035361:Transcription Factor TFIIIB; D014157:Transcription Factors / Q000378:metabolism*; D019474:Transcription Factors, TFIII; D014158:Transcription, Genetic; D000098832:Transcription Factor TFIIIC
D000952:Antigens, Polyomavirus Transforming; D002457:Cell Extracts; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012333:RNA, Messenger; D016160:Retinoblastoma Protein; D035361:Transcription Factor TFIIIB; D014157:Transcription Factors; D019474:Transcription Factors, TFIII; C059731:oncogene protein E7, Human papillomavirus type 16; D000098832:Transcription Factor TFIIIC; D012320:RNA Polymerase III