B6.Cg-Psme1/Psme2^tm1Tchi/J

Stock number: 021202
Research areas: Apoptosis Research, Cell Biology Research, Immunology, Inflammation and Autoimmunity Research

Description

These PA28αβ KO mice may be useful for studying the role of the immunoproteasomes in the production of MHC class I ligands.

Detailed description

In this strain, a neo cassette replaces exons 2-10 of the proteasome (prosome, macropain) activator 28 subunit, alpha (Psme1) gene and exons 2-10 of the proteasome (prosome, macropain) activator 28 subunit, beta (Psme2) gene were also deleted, abolishing the expression of both PA28 subunits. Psme1 and Psme2 encode PA28α and PA28β respectively, two subunits that make up the PA28 proteasome activator complex that binds the 20S proteasome. In response to interferon-gamma (IFNγ) or tumor necrosis factor-alpha (TNF-α), cytokines that are released in the early stages of viral infections, catalytic immunosubunits are rapidly assembled to form immunoproteasomes. These specialized proteasomes are formed in most cells, including lymphoid cells, and have a relatively short life span of a few days. They process MHC class I Ag and play a role in CD8⁺ T cell proliferation. PA28 enhances the generation of MHC class I Ag by altering the cleavage preferences of the immunoproteasome. Homozygous mice are viable and fertile. PA28α and PA28β expression is increased upon stimulation with IFNγ. These mice show a reduction of MHC class I-binding peptides in lymphoid cells.

Development

A targeting vector was designed to replace exons 2-10 of the proteasome (prosome, macropain) activator 28 subunit, alpha (Psme1) gene with a neomycin resistance (neo) cassette in reverse orientation to the gene. This vector also deleted exons 2-10 of the proteasome (prosome, macropain) activator 28 subunit, beta (Psme2) gene. The construct was electroporated into (C57BL/6 x CBA)F1-derived TT2 embryonic stem (ES) cells. Correctly targeted ES cells were injected into ICR blastocysts and the resulting chimeric males were bred to C57BL/6 mice. These mice were to C57BL/6 mice for at least 10 generations. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Psme1/Psme2^tm1Tchi
Name: targeted mutation 1, Tomoki Chiba
MGI accession ID: MGI:2388600
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Psme1
Marker name: proteasome (prosome, macropain) activator subunit 1 (PA28 alpha)
Chromosome: 14
Strain of origin: (C57BL/6NCrlj x CBA/JNCrlj)F1
Molecular note: A targeting construct where exons 2-10 of Psme1 were replaced with a neomycin resistant cassette and exons 2-10 of Psme2 were deleted was used to disrupt both loci in a single homologous recombination event. The sequence of Cgi112 (1500005A01Rik), the gene located between Psme1 and Psme2, remained unchanged. Northern blot and Western blot analysis of mouse embryonic fibroblast (MEFs) cultured from homozygous mutant embryos confirmed the absence of Psme1 and Psme2 gene expression.
General note: Homozygous mutant animals bred well and appear healthy with no observable abnormalities.

Allele

Symbol: Psme1/Psme2^tm1Tchi
Name: targeted mutation 1, Tomoki Chiba
MGI accession ID: MGI:2388601
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Psme2
Marker name: proteasome (prosome, macropain) activator subunit 2 (PA28 beta)
Chromosome: 14
Strain of origin: (C57BL/6NCrlj x CBA/JNCrlj)F1
Molecular note: A targeting construct where exons 2-10 of Psme1 were replaced with a neomycin resistant cassette and exons 2-10 of Psme2 were deleted was used to disrupt both loci in a single homologous recombination event. The sequence of Cgi112 (1500005A01Rik), the gene located between Psme1 and Psme2, remained unchanged. Northern blot and Western blot analysis of mouse embryonic fibroblast (MEFs) cultured from homozygous mutant embryos confirmed the absence of Psme1 and Psme2 gene expression.
General note: Homozygous mutant animals breed well and appear healthy with no observable abnormalities.