Mammary tumorigenesis in C3Hf/Ki mice: examination of germinal mouse mammary tumor viruses and the int-1 and int-2 putative proto-oncogenes.
The organization and expression of endogenous mouse mammary tumor virus (MMTV) proviruses in normal and neoplastic C3Hf/Ki tissues were examined. MMTV-containing EcoRI, HindIII, BamHI and PstI restriction fragments of C3Hf/Ki DNA were identical to those of C3H/StWi DNA. The full-length endogenous MMTV Units Ia (Mtv-7), II (Mtv-8), III (Mtv-9) and IV (Mtv-10), in addition to the subgenomic endogenous MMTV Units I (Mtv-6) and IX (Mtv-14), were germinally transmitted in C3Hf/Ki DNA. The previously uncharacterized Mtv-7 was contained in EcoRI fragments of 16.7 and 11.7 kbp. The endogenous MMTV Unit V (Mtv-1), which is responsible for virus production and mammary tumorigenesis in C3Hf/He mice, was absent from C3Hf/Ki DNA. The 9.0 kb gag-pol, the 3.8 kb env and the 1.7 kb LTR MMTV RNA transcripts were present in C3Hf/Ki mammary glands. MMTV proviruses, in addition to the endogenous C3Hf/Ki MMTV complement, were not detected in C3Hf/Ki mammary tumor DNA. The DNA organization and RNA expression of the putative mammary proto-oncogene regions int-1 and int-2 were also examined in C3Hf/Ki mammary tumors. The int-1 and int-2 regions did not appear rearranged, amplified, or expressed in C3Hf/Ki mammary tumors. These studies indicate that MMTV proviral activation of the int proto-oncogenes is not necessary for C3Hf/Ki mammary tumorigenesis.
Popko
B J
BJ
Pauley
R J
RJ
D000818:Animals; D002472:Cell Transformation, Viral; D004273:DNA, Neoplasm / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D005786:Gene Expression Regulation; D005814:Genes, Viral; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000382:microbiology*; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D051379:Mice; D008809:Mice, Inbred C3H / Q000235:genetics / Q000382:microbiology; D009857:Oncogenes; D014178:Translocation, Genetic
D004273:DNA, Neoplasm; D004279:DNA, Viral