SM/J

Stock number: 000687
Strain synonyms: small
Research areas: Cardiovascular Research, Developmental Biology Research, Diabetes and Obesity Research, Hematological Research, Immunology, Inflammation and Autoimmunity Research, Mouse/Human Gene Homologs

Description

SM/J mice carry a number of rare polymorphic alleles and are often matched to other strains for quantitative trait locus analysis. These mice are susceptible to diet-induced obesity and diet-induced atherosclerosis. SM/J mice exhibit a hyperresponsiveness to B cell mitogens. Small in size at birth and through weaning, SM/J mice attain a normal body weight as they age.

Detailed description

SM/J mice carry a number of rare polymorphic alleles and are often matched to LG/J (Stock No. 000675), A/J (Stock No. 000646) or NZB/BINJ (Stock No. 000684) for quantitative trait locus analysis. These mice are susceptible to diet-induced obesity and diet-induced atherosclerosis. SM/J mice exhibit a hyperresponsiveness to B cell mitogens (Clark et al. 1981, Engel et al. 1981). A point mutation in Neu1 is responsible for a partial deficiency of lysosomal neuraminadase and may explain the altered immune response (Rottier et al. 1998). Small in size at birth and through weaning, SM/J mice attain a normal body weight as they age.

Development

SM/J, created by MacArthur in 1939 from crosses involving 7 inbred strains - among them DBA - followed by inbreeding with selection for small body size, is segregating white-bellied agouti (A^w) vs. nonagouti (a) at the agouti locus.

Allele

Symbol: Il3ra^m1
Name: mutation 1
MGI accession ID: MGI:3652833
Generation method: Spontaneous
Marker symbol: Il3ra
Marker name: interleukin 3 receptor, alpha chain
Chromosome: 14
Strain of origin: multiple strains
Molecular note: Sequence analysis revealed A/J mice lack the sequence corresponding to exon 8, which encodes 10 amino acid residues in the extracellular domain. Aberrant splicing was due to a 5 base pair deletion at the branch point in intron 7.
General note: This allele has been identified in A/J, A/WySnJ, A/HeJ, C58/J, RF/J, AKR/J, SM/J, BUB/BnJ, CE/J, and NZB/B1NJ. see J:24918.

Allele

Symbol: Neu1^a
Name: a variant
MGI accession ID: MGI:3042795
Generation method: Not Applicable
Marker symbol: Neu1
Marker name: neuraminidase 1
Chromosome: 17
Strain of origin: SM/J
Molecular note: Sequencing of the a allele revealed 5 nucleotide differences compared to the b allele. These changes alter the amino acid residues 11, 15, 17, 19 and 209 of the encoded protein from Gly, Tyr, Ala, Arg and Leu to Arg, Cys, Val, Cys and Ile, respectively. This encoded protein has 85-95% less activity than the protein encoded by the b allele as demonstrated in an in vitro assay. Further studies attributed most of the activity loss to the variation at position 209. Later studies detected 4 silent mutations in the signal peptide sequence and 2 mutations (c.-240C>T and c.-519G>A) in the promoter region. The mutation c.-519G>A creates a novel binding site for Nkx3-1 and Nkx3-2. In vitro assays demonstrated that binding of Nkx3-2 specifically represses promoter driven expression.
General note: Low activity determined by the Neu1^a allele occurs in the SM/J inbred strain and in wild mice in the area of Ann Arbor, Michigan; all other inbred strains have high activity determined by the Neu1^b allele. Heterozygotes have intermediate activity. Neuraminidase removes extra sialic acid residues from these enzymes. The defective neuraminidase of Neu1^a> mice, by failing to remove the extra sialic acid, changes their electrophoretic mobility (J:6480). Level of activity of neuraminidase in activated T lymphocytes is also depressed in Neu1^a/Neu1^a mice (J:7976).

Allele

Symbol: Gpr84^del
Name: deletion
MGI accession ID: MGI:5812913
Generation method: Spontaneous
Attributes: Null/Knockout
Marker symbol: Gpr84
Marker name: G protein-coupled receptor 84
Chromosome: 15
Strain of origin: multiple strains
Molecular note: This spontaneously arising frameshift deletion is located in exon 2 at position 103308576 bp (NCBI Build 37) and results in a premature stop codon. The mutation is predicted to result in a truncated protein lacking the transmembrane domains 4-7. The inbred strains BDP/J, DBA/1J, DBA/2J, I/LnJ, FVB/NJ, LG/J, MRL/MpJ, NODShi/LtJ, NOR/LtJ, P/J, PL/J, SKHIN/Sprd, SJL/J, SM/J are homozygous for the deletion. The allele is segregating in the outbred stocks ICR and CD-1.

Allele

Symbol: Ogg1^m1
Name: mutation 1
MGI accession ID: MGI:6157073
Generation method: Spontaneous
Attributes: Not Applicable
Marker symbol: Ogg1
Marker name: 8-oxoguanine DNA-glycosylase 1
Chromosome: 6
Strain of origin: various
Molecular note: A G-to-A change at the fifty-ninth nucleotide in exon 7 resulted in a substitution of arginine with histidine at position 336 (p.R336H) in a putative nuclear localization signal. The mutation led to disruption of the nuclear localization of the enzyme, although the activity remained normal.

Allele

Symbol: Hbb^s
Name: single
MGI accession ID: MGI:2677684
Generation method: Not Applicable
Marker symbol: Hbb
Marker name: hemoglobin beta chain complex
Chromosome: 7
Strain of origin: C57BL/6
Molecular note: This natural variant identified by protein sequencing, produces a single beta globin with one reactive cysteine (betaCyst13). Two structurally identical beta globins migrate during electrophoresis in a dimer with alpha globin as a single band, therefore the s designation.

Allele

Symbol: B2m^a
Name: a variant
MGI accession ID: MGI:6357680
Generation method: Spontaneous
Attributes: Not Applicable
Marker symbol: B2m
Marker name: beta-2 microglobulin
Chromosome: 2
Strain of origin: multiple strains
Molecular note: The a variant is slightly slower running on SDS PAGE and was found to have an aspartic acid at amino acid position 85. This allele is found in A, BALB/c, LP and most other strains.