B6.129P2-Trpm8^tm1Jul/J

Stock number: 008198
Product name: TRPM8 KO
Research areas: Research Tools, Sensorineural Research

Description

These transient receptor potential cation channel, subfamily M, member 8 (Trpm8) knock-out mutant mice may be useful for neurological studies including thermosensation over a wide range of cold temperatures, detection of cold thermal stimuli by primary afferent sensory neurons, nociceptive processing, and pain response behavior.

Detailed description

Mice homozygous for this TRPM8 targeted mutation are viable and fertile, with no differences in core body temperature compared to wildtype. Functional TRPM8 transcripts are absent in trigeminal ganglia from homozygous mutants however,a truncated, non-functional transcript is generated. Immunostaining of trigeminal ganglia, corneal afferents, and spinal cord dorsal horn reveals loss of TRPM8 expression in homozygous mutants. TRPM8-deficient mice exhibit behavioral deficits in their ability to discriminate between cold and warm surfaces, or to respond to evaporative cooling. Homozygous mice are not completely cold insensitive as they avoid contact with surfaces below 10 C (albeit with reduced efficiency). Cultured sensory neurons and intact sensory nerve fibers from TRPM8-deficient mice exhibit profoundly diminished responses to cold. These TRMP8 (transient receptor potential cation channel, subfamily M, member 8 (also called TRP melastatin 8 or cold and menthol receptor 1 (CMR1))) mutant mice may be useful for neurological studies including thermosensation over a wide range of cold temperatures, detection of cold thermal stimuli by primary afferent sensory neurons, nociceptive processing, and pain response behavior.

Development

A targeting vector was designed to replace 569 base pairs of genomic sequence within exons 13 and 14 (encoding amino acids 594-661 within the presumptive cytoplasmic amino-terminal domain) of the targeted gene with an ACN cassette. The ACN cassette, containing the neomycin resistance gene and cre recombinase gene under the control of angiotensin-converting enzyme promoter, is flanked by loxP sites. Cre-mediated recombination during spermatogenesis removed the cassette, leaving one loxP site and introducing a stop codon before and a frameshift after the deleted segment. The construct was electroporated into 129P2/OlaHsd-derived E14Tg2A.4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts, and chimeric males were bred to C57BL/6 females. The Donating investigator reported that heterozygous males were then backcrossed to C57BL/6 females (see SNP note below) for 4 generations. Upon arrival at The Jackson Laboratory, mice were backcrossed to C57BL/6J for at least one generation to establish the colony. The Y chromosome may not have been fixed to the C57BL/6N genetic background.

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, all 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a C57BL/6N genetic background.

 

Allele

Symbol: Trpm8^tm1Jul
Name: targeted mutation 1, David Julius
MGI accession ID: MGI:3716518
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Trpm8
Marker name: transient receptor potential cation channel, subfamily M, member 8
Chromosome: 1
Strain of origin: 129P2/OlaHsd
Molecular note: The self excising ACN cassette was inserted to replace exons 13 and 14. Amino acids 594-661, located in the presumptive cytoplasmic amino-terminal domain, were deleted from the locus, introducing a premature stop codon before and a frame shift after the deleted region. RT-PCR confirmed absence of transcript from mutant trigeminal ganglia.