B6(FVB)-Serpina3g^tm1.1Arp/J

Stock number: 022524
Research areas: Immunology, Inflammation and Autoimmunity Research, Internal/Organ Research, Research Tools, Virology Research

Description

In this strain exon 4 of the Serpina3g (serine (or cysteine) peptidase inhibitor, clade A, member 3G ) gene is deleted. These mice may be useful in studies of homeostatic proliferation, long-term maintenance of memory CD8⁺ T cell populations, and erythropoiesis.

Detailed description

The Serpina3g gene encodes for the SPI2A serine protease inhibitor, which acts to inhibit cysteine cathepsins and is expressed at low levels in naive CD8⁺ T cells and is upregulated in effector cells. These mice carry a targeted mutation of the Serpina3g gene in which exon 4 has been deleted. Mice that are homozygous for the targeted mutation are viable and fertile. No gene product (mRNA) is detected in homozygous animals. Homozygotes develop a reduced number memory phenotype CD44^hi CD8⁺ T cells as they age, and exhibit decreased homeostatic proliferation of memory T cells. After lymphocytic choriomeningitis virus (LCMV) infection, antigen specific CD8⁺ T cells do not persist as long as wildtype controls. Homozygotes exhibit severely impaired erythropoiesis in response to acute anemia or erythropoietin dosing.

Development

A targeting vector designed by Dr. Philip G. Ashton-Rickardt (Imperial College London) containing a floxed NEO cassette was inserted downstream of exon 4, and a second loxP site was inserted upstream of exon 4. The construct was electroporated into C57BL/6 derived PRX-B6tN-1 (Primogenix) embryonic stem (ES) cells, which were transiently transfected with a vector containing the Cre-recombinase gene under the control of the cytomegalovirus promoter to remove the selection cassette. Correctly targeted ES cells that retained the floxed exon 4 were injected into C57BL/6 blastocysts. The resulting chimeric animals were crossed to C57BL/6 mice. The mice were then crossed to transgenic mice, on the C57BL/6 background, that express Cre recombinase under the control of the adenovirus EIIa promoter, to excise exon 4. The Cre recombinase transgene was subsequently bred out of the line. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.

Allele

Symbol: Serpina3g^tm1.1Arp
Name: targeted mutation 1.1, Philip Ashton-Rickardt
MGI accession ID: MGI:5450829
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Serpina3g
Marker name: serine (or cysteine) peptidase inhibitor, clade A, member 3G
Chromosome: 12
Strain of origin: C57BL/6J
Molecular note: A loxP site was inserted upstream of exon 4. A floxed neo cassette was inserted downstream of exon 4. Cre-mediated recombination removed exon 4 and the neo cassette. Experiments confirmed the absence of transcript expression in splenocytes.
General note: ES cell line = PRX-B6tN-1 (C57BL/6J).