NOD.Cg-Cmah^em1Guru Prkdc^scid Il2rg^tm1Wjl/GuruJ

Stock number: 031900
Product name: NSG-cmah^-/-
Strain synonyms: NSG-cmah<->
Research areas: Cancer Research, Cardiovascular Research, Developmental Biology Research, Hematological Research, Immunology, Inflammation and Autoimmunity Research, Internal/Organ Research, Research Tools, Virology Research

Description

NSG-cmah^-/- mice are NOD.scid.Il2Rγc^null ("NSG") animals with a Cmah knock-out allele. The NSG platform is permissive for xenograft/human tumor growth, with mouse CMAH-deficiency modeling the universal human inactivating mutation in CMAH. NSG-cmah^-/- mice are designed to provide an improved environment for transplantation of human immune cells, and may be useful in studying viral vectors or infectious agents that are sensitive to human-like sialylation of mouse glycoproteins (e.g., generating a human B cell repertoire for studying HIV-1).

Detailed description

NSG-cmah^-/- mice are NOD.scid.Il2Rγc^null ("NSG"; Stock No. 005557) animals also harboring the Cmah^em1Guru knock-out allele (cmah^-; a 27 bp deletion in Cmah exon 6). Females homozygous for all three mutations, and males that are homozygous for Cmah^em1Guru, homozygous for scid and hemizygous for the X-linked Il2Rγc^null mutation, may be collectively referred to as NSG-cmah^-/- mice.

Although viable and fertile, NSG-cmah^-/- mice are immunodeficient: they have no mature T cells or B cells, lack functional natural killer (NK) cells, have reduced numbers of lymphocytes and myeloid dendritic cells, and are deficient in cytokine signaling. The NSG platform is permissive for xenograft/human tumor growth. Because humans universally have an inactivating mutation in CMAH, mice with CMAH-deficiency have human-like sialylation of mouse glycoproteins.

NSG-cmah^-/- mice are a CMAH-deficient NSG mouse model designed to provide an improved environment for transplantation of human immune cells, and may be useful for studying protein glycosylation/sialylation patterns (i.e., Neu5Ac --> Neu5Gc), interactions with sialic acid-binding Ig-like lectins (Siglecs) and immune cell activation (monocytes, T cells, B cells, etc.) of viral vectors or infectious agents that are sensitive to human-like sialylation of mouse glycoproteins.
For example, transplantation of human hematopoietic stem cells info NSG-cmah^-/- mice leads to broad B cells repertoire, higher sensitivity to human immunodeficiency virus type 1 (HIV-1) infection and enhanced proliferation of transplanted peripheral blood lymphocytes. The mice showed low effects on the clearance of human immunoglobulins and enhanced transduction efficiency of recombinant adeno-associated viral vector rAAV2/DJ8. [Dagur et al. 2019 BMC Immunol. 20:2 (PMID:30616506)]

Maintenance Note: Similar to other immunodeficient strains, maintaining NSG-cmah^-/- mice in high health status (specific pathogen-free) vivaria promotes overall colony health. If NSG-cmah^-/- animals are maintained in low health barrier rooms, the use of medicated water (e.g., sulfatrim/trimethoprim-sulfa or enrofloxacin/Baytril) is suggested to increase overall colony health.

View our Resources for the NSG mouse model, including discussion forum, immunodeficient model comparison and categorized, up-to-date references.

Development

NSG-cmah^-/- mice are NOD.scid.Il2Rγc^null ("NSG") animals with the Cmah^em1Guru knock-out allele (cmah^-). NSG-cmah^-/- mice harbor several mutations, as described below.

NSG mice are non-obese diabetic animals (NOD/ShiLtJ) harboring the spontaneous severe combined immunodeficiency mutation (Prkdc^scid) on chromosome 16 and the Il2Rγc^null mutation at ~101 Mbp on the X chromosome (Il2rg^tm1Wjl created by Dr. Warren J. Leonard [NIH]). NSG mice are described and available from The Jackson Laboratory Repository as Stock No. 005557.

The Cmah^em1Guru knock-out allele (cmah^-) was created in the laboratory of Drs. Channabasavaiah B. Gurumurthy and Larisa Y. Poluektova (University of Nebraska Medical Center) using CRISPR/Cas9 genome engineering in NSG mouse zygotes (from Stock No. 005557). Exon 6 of the cytidine monophospho-N-acetylneuraminic acid hydroxylase locus (Cmah) on chromosome 13 was targeted with two specific single guide RNAs (Cmah SgRNAl-CCAGGTCCGTTAAATGCACA and Cmah SgRNA2-TGAAATATATCAACCCTCCA). Genotyping identified founder male #2 with modification in the Cmah locus. This founder was bred to NSG females for germline transmission. Genotyping and sequencing of the offspring identified the cmah^- allele to be a 27 bp deletion in the target site (one nucleotide in intron 5-6 and the remaining 26 nucleotides in exon 6). Breeding one more generation to NSG mice established the NSG-cmah^- colony. Thereafter, the donating investigator maintained their colony by breeding females homozygous for cmah^-, homozygous for scid and homozygous for Il2Rγc^null with males homozygous for cmah^-, homozygous for scid and hemizygous for the X-linked Il2Rγc^null. The mice have not been characterized for off-target mutations to date (September 2018).

In 2018, NSG-cmah^- mice (albino) were sent to The Jackson Laboratory Repository as Stock No. 031900.

Allele

Symbol: Prkdc^scid
Name: severe combined immunodeficiency
MGI accession ID: MGI:1857113
Generation method: Spontaneous
Synonyms: scid
Marker symbol: Prkdc
Marker name: protein kinase, DNA activated, catalytic polypeptide
Marker synonyms: DNAPDcs; DNAPK; DNA-PK; DNAPKc; DNA-PKC; DNA-PKcs; DNPK1; DOXNPH; dxnph; HYRC; HYRC1; IMD26; p350; S473K; slip; XRCC7
Chromosome: 16
Strain of origin: C.BKa-Igh^b/Icr
Site of expression: T and B lymphocytes.
Molecular note: A T-to-A transversion point mutation at a position corresponding to codon 4046 (codon 4095 in transcript ENSMUST00000023352.8) created a premature stop codon (p.Y4046*).

Allele

Symbol: Il2rg^tm1Wjl
Name: targeted mutation 1, Warren J Leonard
MGI accession ID: MGI:1857455
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: [KO]gammac; CD132^-; gammac^-; gc^-; Il2rg^tm1Wjll; IL2Rgamma^null
Marker symbol: Il2rg
Marker name: interleukin 2 receptor, gamma chain
Marker synonyms: [g]c; Ab2-183; Cd132; CIDX; common cytokine receptor gamma chain; common gamma chain; gamma C receptor; gamma(c); gammaC; gc; IL-2RG; IMD4; P64; SCIDX; SCIDX1
Chromosome: X
Strain of origin: 129S4/SvJae
Site of expression: Primarily lymphoid cells.
Molecular note: A neomycin resistance cassette replaced part of exon 3 and all of exons 4 - 8 of the gene, resulting in the loss of most of the extracellular domain and all of the transmembrane and cytoplasmic domains of the protein.

Allele

Symbol: Cmah^em1Guru
Name: endonuclease-mediated mutation 1, Channabasavaiah Gurumurthy
MGI accession ID: MGI:6198533
Generation method: Endonuclease-mediated
Attributes: Null/Knockout
Synonyms: cmah^-
Marker symbol: Cmah
Marker name: cytidine monophospho-N-acetylneuraminic acid hydroxylase
Marker synonyms: CMAH; Cmahp; CMP-NeuAc hydroxylase; CSAH
Chromosome: 13
Strain of origin: NOD.Cg-Prkdc^scid Il2rg^tm1Wjl/SzJ
Molecular note: CRISPR/cas9 endonuclease mediated genome editing is used to introduce a 27 bp deletion in the target site (one nucleotide in intron 5-6 and the remaining 26 nucleotides in exon 6) on chromosome 13.