Avian nephroblastomas induced by a retrovirus (MAV-2) lacking oncogene. II. Search for common sites of proviral integration in tumour DNA.
To demonstrate the existence of a common site of integration in independent tumour clones, restriction mapping of the vicinity of integrated MAV-2 proviruses in nephroblastoma DNA was performed, using Southern hybridization with an MAV-2 specific probe U3(pAT). The results have shown that (1) nephroblastomas are of semiclonal origin. (2) Nephroblastoma cells contain an average of 5 clonally located integrated proviruses per diploid genome; they do not contain any detectable amount of non-integrated proviruses. (3) In the DNA from independent nephroblastoma clones, there appear at an increased frequency Tth111I fragments of 14.6 and 17.8 kb that hybridize with the U3(pAT) probe. Considering a random selection of integration sites, such coincidence is of little probability. Thus we suppose that these fragments represent a common site(s) of integration with an MAV-2 proviral insert. Two hypotheses concerning possible mechanisms of nephroblastoma induction are discussed: proto-oncogene insertional activation and anti-oncogene insertional inactivation.
Pecenka
V
V
Institute of Molecular Genetics, Czechoslovak Academy of Sciences, Praha.
Dvorák
M
M
Karafiát
V
V
Sloncová
E
E
Hlozánek
I
I
Trávnícek
M
M
Ríman
J
J
D000818:Animals; D001354:Avian Leukosis Virus / Q000235:genetics*; D009189:Avian Myeloblastosis Virus / Q000235:genetics*; D002645:Chickens; D004262:DNA Restriction Enzymes; D004273:DNA, Neoplasm / Q000235:genetics* / Q000302:isolation & purification; D004279:DNA, Viral / Q000235:genetics* / Q000302:isolation & purification; D005814:Genes, Viral; D006378:Helper Viruses / Q000235:genetics*; D007680:Kidney Neoplasms / Q000382:microbiology*; D009693:Nucleic Acid Hybridization; D009857:Oncogenes; D011533:Proviruses / Q000235:genetics*; D009396:Wilms Tumor / Q000382:microbiology*
D004273:DNA, Neoplasm; D004279:DNA, Viral; D004262:DNA Restriction Enzymes