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Identification of an IL‐15‐limiting C57BL/6 mutant mouse through ENU genome‐wide mutagenesis
Author(s) -
Kung John T,
Tsai PiFang,
Tan SihHui,
Chang MeiLing
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.2_supplement.427
Subject(s) - biology , genetics , mutant , gene , microbiology and biotechnology , phenotype , exon , mutagenesis , offspring , genome , pregnancy
With the human genome sequenced, the race is on to understand the functions of the 30,000 or so genes. Ethyl‐nitrosourea (ENU) was used to treat C57BL/6 (B6) male mice, followed by a 3‐generation breeding scheme to generate G3 mice that were screened for immunological phenotypes under recessive genetic control. The primary phenotype of one mutant, P191, was depressed CD44 expression among CD8 + T cells. Subsequently, recessive mode of inheritance was confirmed by mating an affected G3 male to wildtype B6 females to generate F2 offspring. No affected phenotype was found in F1 mice and approximately 1 in 4 F2 mice were pheno‐deviants. Affected G3 mice were outcrossed to generated F2 offspring and the affected F2 mice were subjected to linkage analysis by haplotype interval mapping (Neuhaus and Beier, 1998. Mammalian Genome 9, 150–154). The mutant gene was found to be linked to chromosome 8. Through candidate gene sequencing of genes located within the linked region, a single C to T base synonomous mutation was identified in the coding region of exon 7 which results in an alternatively spliced IL‐15 mRNA that is 48‐bp smaller than the wildtype mRNA. This alternatively spliced form of IL‐15 mRNA is expected to encode an IL‐15 protein with an internal 18 amino acid deletion. While the P191 phenotype is similar to that of IL‐15‐null mice, full‐length IL‐15 mRNA was detected, although at reduced levels. Thus, P‐191 mouse may be used as a model of limiting IL‐15 protein and can be used to probe immune functions of IL‐15‐dependent immune functions.