A Transgenic MMTV-Flippase Mouse Line for Molecular Engineering in Mammary Gland and Breast Cancer Mouse Models

J Mammary Gland Biol Neoplasia. 2019 Mar;24(1):39-45. doi: 10.1007/s10911-018-9412-4. Epub 2018 Sep 12.


Genetically engineered mouse models have become an indispensable tool for breast cancer research. Combination of multiple site-specific recombination systems such as Cre/loxP and Flippase (Flp)/Frt allows for engineering of sophisticated, multi-layered conditional mouse models. Here, we report the generation and characterization of a novel transgenic mouse line expressing a mouse codon-optimized Flp under the control of the mouse mammary tumor virus (MMTV) promoter. These mice show robust Flp-mediated recombination in luminal mammary gland and breast cancer cells but no Flp activity in non-mammary tissues, with the exception of limited activity in salivary glands. These mice provide a unique tool for studying mammary gland biology and carcinogenesis in mice.

Keywords: Breast cancer; Flippase; Lineage tracing; MMTV promoter; Mammary gland; Transgenic mice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carcinogenesis / genetics*
  • Carcinogenesis / pathology
  • DNA Nucleotidyltransferases / genetics*
  • Disease Progression
  • Epithelial Cells / pathology
  • Female
  • Genes, Reporter / genetics
  • Genetic Vectors / administration & dosage
  • Genetic Vectors / genetics
  • Luminescent Proteins / genetics
  • Mammary Glands, Animal / cytology
  • Mammary Glands, Animal / pathology*
  • Mammary Neoplasms, Experimental / genetics*
  • Mammary Neoplasms, Experimental / pathology
  • Mammary Tumor Virus, Mouse / genetics*
  • Mice
  • Mice, Transgenic
  • Microinjections
  • Promoter Regions, Genetic / genetics
  • Recombination, Genetic
  • Red Fluorescent Protein
  • Salivary Glands / pathology
  • Tumor Microenvironment / genetics


  • Luminescent Proteins
  • DNA Nucleotidyltransferases
  • FLP recombinase