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. 2007 Apr 25;3(5):281–291. doi: 10.7150/ijbs.3.281

Figure 3.

Figure 3

Northern analysis of MMTV-BRCA1 transgenic mice. (A) The mammary glands of 13-week-old virgin MMTV-BRCA1 (line 6) transgenic animals in diestrus were analyzed for transgene mRNA expression with a radiolabeled BRCA1 cDNA probe. The ~5.6kb BRCA1 transgene mRNA is present in transgenic animals, but not in nontransgenic controls. Homozygous transgenic mice express more human BRCA1 mRNA than hemizygous mice. Hybridization to cyclophilin was performed to control for RNA loading on the gel. (B) The mammary glands of 13-week-old hemizygous MMTV-BRCA1t340 animals (line 2) were analyzed for transgene mRNA expression by Northern hybridization with a radiolabeled BRCA1t340 cDNA probe during different stages of the estrous cycle. BRCA1t340 expression is observed in transgenic mice, but not in nontransgenic controls. (C) The mammary glands of 13-week-old virgin hemizygous MMTV-BRCA1 (line 6) and MMTV-BRCA1sv (line 90) animals in diestrus were analyzed for transgene mRNA expression with a radiolabeled BRCA1 cDNA probe. Despite similar transgene copy numbers, MMTV-BRCA1sv (line 90) mRNA is at a significantly higher level than MMTV-BRCA1 (line 6) mRNA.