ENU-induced G to A transition at base pair 129,558,127 (v38) on chromosome 4, or base pair 15,515 in the GenBank genomic region NC_000070 for the Lck gene. The mutation corresponds to residue 149 in the NM_001162432 mRNA sequence in exon 2 of 13 total exons, or at position 191 bp of the NM_001162433 mRNA sequence in exon 2 of 13 total exons, or at position 1,050 of the NM_010693 mRNA sequence in exon 1 of 12 total exons. The mutation results in a cysteine to tyrosine substitution at position 31 (C31Y) in the Lck protein isoform encoded by NM_001162432 and a cysteine to tyrosine substitution at position 25 (C25Y) in the Lck protein isoforms encoded by NM_001162433 and NM_010693.

Homozygous: Mice showed an increase in the B:T cell ratio as well as a decrease in the CD4+ to CD8+ T cell ratio caused by a diminished frequency of CD4+ T cells and CD4+ T cells in CD3+ T cells coupled with an increased frequency of CD8+ T cells in CD3+ cells, all in the peripheral blood. Some mice also had an increase in the CD44 mean fluorescence intensity on total T cells and on CD8+ T cells in the peripheral blood.

Heterozygous: No signficant abnormal phenotype detected.

Original mutant was a C57BL/6J G3 ENU-induced mutant; all subsequent crosses to maintain strain were on C57BL/6J background only.

Wild-type littermates or C57BL/6J mice

The MMRRC Centers have developed a genetic QC pipeline using MiniMUGA array genotyping to provide additional information on strain backgrounds for MMRRC congenic and inbred strains. For more information on when data may be available, or to request genotyping for a strain of interest, please contact . Older strains may not have this information.