The different activation of int genes in mammary carcinomas developed in three mouse strains harboring mouse mammary tumor viruses derived from DD/Tbr.
RNA expressions of common integration site (int) genes and several oncogenes were investigated in mammary carcinomas spontaneously developed in different three strains of mice; DD/Tbr, NIH Swiss and BALB/c which harbor DD-MMTV derived from DD/Tbr mouse. Latter two strains of mice were designated NIH/Mtv+ and BALB/Mtv+, respectively. An increased expression of int-1 (wnt-1) and int-2 genes was observed in 56% (9/16) and 50% (8/16) of mammary carcinomas of DD/Tbr mice, respectively. Either int-1 or int-2 RNAs were expressed in 81% (13/16) of the carcinomas of DD/Tbr mice. IN NIH/Mtv+ mice, activation of int-1 and int-2 was observed in 41% (7/17) and 24% (4/17) of mammary carcinomas, respectively. Either int-1 or int-2 RNAs were expressed in 47% (8/17) of the carcinomas examined in this strain. In BALB/Mtv+ mice, on the other hand, either int-1 or int-2 gene were transcribed into RNAs at low frequency (33%: 3/9). These results suggest that the frequency of activation of int genes in mammary carcinomas induced by the same DD-MMTV in three strains of mice is genetically defined characteristics of these strains, and that the involvement of int-1 and int-2 genes in virus-induced mammary carcinogenesis may be influenced by genetic properties of animals. The activation of int-1 and int-2 genes did not clearly correlate with an increase in the expression of oncogenes examined; H-ras, K-ras, N-ras, myc, raf, fgr, fms, erB, mos, and src genes.
Okumoto
M
M
Department of Applied Bioscience, University of Osaka Prefecture, Japan.
Nishikawa
R
R
Iwai
M
M
Iwai
Y
Y
Imai
S
S
Mori
N
N
Takamori
Y
Y
Yagasaki
O
O
D000818:Animals; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D008325:Mammary Neoplasms, Experimental / Q000235:genetics* / Q000382:microbiology; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics*; D009857:Oncogenes / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics*; D014158:Transcription, Genetic
D012334:RNA, Neoplasm