Episomal amplification or chromosomal integration of the viral genome: alternative pathways in hamster polyomavirus-induced lymphomas.
The state and expression of the hamster polyomavirus genome in a large panel of virus-induced lymphomas have been investigated. The viral genome is present within tumor cells either as abundant nonrandomly deleted extrachromosomal copies or as a single copy integrated into cellular DNA. We show that these two physical states are likely to be functionally equivalent: first, deletion and integration of the viral genome both inactivate the late coding region; second, the amount of viral early RNAs yielded by a single integrated copy appears to be very similar to that associated with several thousands of extrachromosomal copies of the viral genome. These data underline two essential requisites for hamster polyomavirus to become lymphomagenous: suppression of the late coding functions of the viral genome and expression of the viral oncogenes above a threshold level.
Mazur
S
S
Laboratoire d'Oncologie Moléculaire, Centre National de la Recherche Scientifique, Institut Gustave Roussy, Villejuif, France.
Feunteun
J
J
de La Roche Saint André
C
C
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002875:Chromosomes / Q000821:virology; D003043:Cocarcinogenesis; D006224:Cricetinae; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D005784:Gene Amplification; D017353:Gene Deletion; D016679:Genome, Viral; D008223:Lymphoma / Q000209:etiology; D008954:Models, Biological; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D011120:Polyomavirus / Q000235:genetics* / Q000472:pathogenicity*; D027601:Polyomavirus Infections / Q000209:etiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D014412:Tumor Virus Infections / Q000209:etiology; D016662:Virus Integration / Q000235:genetics*
D017931:DNA Primers; D004279:DNA, Viral; D012333:RNA, Messenger; D012367:RNA, Viral