Effect of CpG-rich sequences in transformation and tumorigenesis by polyomavirus.
To address the question of the role of CpG-rich sequences in gene expression, we investigated the effect of an HTF island on the activity of the polyomavirus middle T (pmt) oncogene. pmt is less transformant and less tumorigenic when it is introduced into cultured cells or newborn rats in the presence of an HTF island. Transformed cells carrying pmt in the vicinity of the HTF island have a propensity to revert at a relatively high rate of about 2 X 10(-3) per cell per generation by a mechanism probably involving methylation of some CpG sites in the island. Our results suggest that HTF islands can function as transcriptional silencers.
Renzo
A
A
Department of Microbiology, University of Sherbrooke, Quebec, Canada.
Bouchard
L
L
Mongeau
C J
CJ
Bastin
M
M
D000818:Animals; D000831:Animals, Newborn; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics; D001483:Base Sequence; D015139:Blotting, Southern; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D004279:DNA, Viral / Q000235:genetics; D015226:Dinucleoside Phosphates; D009857:Oncogenes; D010957:Plasmids; D011120:Polyomavirus / Q000235:genetics* / Q000276:immunology; D051381:Rats; D014158:Transcription, Genetic
D000952:Antigens, Polyomavirus Transforming; D004279:DNA, Viral; D015226:Dinucleoside Phosphates; C015772:CpG dinucleotide