Mouse Strains



B6.Cg-Fastm1.1(ALPP)Chnd/J is a strain of mouse which has been genetically engineered to allow for easy removal of the Fas gene. This makes it especially useful for immunological research and research on apoptosis.[1]


B6.Cg-Fastm1.1(ALPP)Chnd/J is originally derived from the highly common B6 (C57BL/6J) strain. More specifically, mice of the B6(Cg)-Tyrc-2J/J strain provided a line of embryonic stem cells which were used to create chimeras with the desired genetic alteration. Finally, the chimeras were crossed with normal C57BL/6J to create the current strain. Work is now underway to breed out albinism from this line in order to create a new substrain with purely black fur.

Physical Characteristics

B6.Cg-Fastm1.1(ALPP)Chnd/J mice are albino (unlike the black-furred ancestral B6 strain), so their fur is completely white and they have red eyes.

Behavioral Characteristics & Handling

No peer-review literature examining the behavior or handling of this strain could be found. It is generally accepted that C57BL/6J shows less docility during handling than some other commonly used strains such as C57BL/6J.[2] Assuming this characteristic is passed on to B6.Cg-Fastm1.1(ALPP)Chnd/J, researchers requiring highly docile mice may want to avoid this strain.

Health Characteristics

The health characteristics of this strain depend on whether or not it has undergone Cre-mediated recombination. The Fas gene in these mice is flanked by LoxP, which allows it to be excised from their genome via Cre-mediated recombination. Before excision, the mice exhibit relatively normal health.

Fas encodes a receptor which is a member of the tumor necrosis factor receptor family, and plays a central role in immune function as well as in the activation of apoptosis. Binding of the Fas ligand to the Fas receptor induces rapid, controlled cell death. This process is crucial to regulating the level of immune cells in an animal’s bloodstream.[3]

Once the Fas gene has been excised, B6.Cg-Fastm1.1(ALPP)Chnd/J mice do not express the corresponding receptor at all. They subsequently suffer from uncontrolled proliferation of lymphocytes (leukaemia), and autoimmunity that rapidly leads to death.

Major Experimental Uses

The B6.Cg-Fastm1.1(ALPP)Chnd/J strain is of most interest to research on autoimmune disorders and immunology. Since it causes the uncontrolled proliferation of cells, it is also of interest to cancer researchers, especially those focussed on leukaemia and the failure of apoptosis to properly regulate cell numbers.

This strain is arguably more of a blunt instrument than the similar C57BL/6-Fastm1Cgn/J strain,[4] which allows for the Fas receptor to be removed from particular cell types but not others.


  1. 026643 – B6.Cg-Fas/J. 2019. 026643 – B6.Cg-Fas/J. [ONLINE] Available at: [Accessed 07 April 2019].
  2. Maze Engineers. 2019. C57BL/6J Mouse Strain – Maze Engineers. [ONLINE] Available at: [Accessed 07 April 2019].
  3. Waring P, Müllbacher A. 1999. Cell death induced by the Fas/Fas ligand pathway and its role in pathology. Immunol Cell Biol. Aug;77(4):312-7.
  4. 007895 – C57BL/6-Fas/J. 2019. 007895 – C57BL/6-Fas/J. [ONLINE] Available at: [Accessed 07 April 2019].

About Maze Engineers

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