B6;129P2-Lcmt1^{Gt(CSC099)Byg}/SclJ

Stock number: 023332
Research areas: Cancer Research, Cell Biology Research, Developmental Biology Research, Diabetes and Obesity Research, Immunology, Inflammation and Autoimmunity Research, Neurobiology Research, Research Tools

Description

The Lcmt1^{Gt(CSC099)Byg} hypomorphic allele has reduced LCMT1 protein expression. These mice may be useful in studying the role of LCMT1 and serine/threonine protein phosphatase methylation, as well as the biochemical and phenotypic effects of reduced LCMT1 activity.

Detailed description

The Lcmt1^{Gt(CSC099)Byg} hypomorphic allele has a β-geo gene trap cassette inserted into intron 1 of the leucine carboxyl methyltransferase 1 gene (Lcmt1). Due to splicing around the gene trap insertion, Lcmt1 transcript and LCMT1 protein levels are reduced but not eliminated. While Lcmt1 knockout mice are reported to exhibit full embryonic lethality, approximately 20% of mice homozygous for the Lcmt1 hypomorphic allele survive to birth. Homozygous mice (Lcmt1 hypomorphic mice) that survive development are viable and fertile with normal lifespan. Homozygotes have Lcmt1 expression affected in a tissue-dependent manner, with the largest decreases observed in cardiac and skeletal muscle, and smaller decreases in brain, liver, and kidney. Lcmt1 hypomorphic mice have decreased Lcmt1 methyltransferase activity and a concomitant decrease in serine/threonine protein phosphatase (PP2A) methylation. Homozygous mice also show decreased glucose tolerance and increased glucose-stimulated insulin secretion. The expected coat color is black or dark brown.

Development

The pGT0Lxf gene trap vector was designed with a mouse En2 intron-exon splice acceptor, a β-geo fusion reporter protein (β-galactosidase and neomycin phosphotransferase) and SV40 polyadenylation sequence. This gene trap vector was electroporated into 129P2/OlaHsd-derived E14TG2a embryonic stem (ES) cells. ES cells found to have a single gene trap vector randomly inserted into intron 1 of the leucine carboxyl methyltransferase 1 locus (Lcmt1) were identified and named line CSC099. Specifically, the gene trap cassette is located 19,455 nucleotides into intron 1 (or at position 19,729 of the gene [counting from the transcriptional start site in exon 1 and the first base of the initiating ATG codon designated as position 168]). Sequencing of the insertion site additionally revealed the insertion of 3 exogenous nucleotides at the 5prime end of the insertion site, as well as the truncation of 194 nucleotides from the 5prime end of the β-geo gene trap cassette. These CSC099 ES cells were injected into recipient blastocysts. Chimeric males were bred with C57BL/6 females to establish the colony. Mice heterozygous for the Lcmt1^{Gt(CSC099)Byg} hypomorphic allele were backcrossed to C57BL/6 mice for at least three generations prior to sending to The Jackson Laboratory Repository in 2013. Upon arrival, males were used to cryopreserve sperm. To establish our living Lcmt1^{Gt(CSC099)Byg} mouse colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J inbred females (Stock No. 000664).

Allele

Symbol: Lcmt1^{Gt(CSC099)Byg}
Name: gene trap CSC099, BayGenomics
MGI accession ID: MGI:3875917
Generation method: Gene trapped
Attributes: Reporter; Null/Knockout
Marker symbol: Lcmt1
Marker name: leucine carboxyl methyltransferase 1
Chromosome: 7
Strain of origin: 129P2/OlaHsd
Molecular note: The beta-geo containing gene trap vector inserted into intron 1. This allele is hypomorphic.