This Coch knockout strain exhibits more susceptible to bacterial infection and has diminished secreted cytokine levels in response to bacterial infection challenge. These mice may be useful in studies of innate immune responses to bacteria and age-related hearing loss such as DFNA9 (deafness, autosomal dominant 9).
Junying Yuan, Harvard Medical School
The extracellular matrix protein cochlin is encoded by the Coch gene. This highly conserved protein is expressed in the inner ear and follicular dendritic cells. These mice carry a targeted mutation for the Coch, coagulation factor C homolog (Limulus polyphemus), gene, in which exons 7 through 11 and part of exon 12 are deleted. Exons 7 through 11 code for amino acids 147-552, the two von Willebrand factor type A domains. Mice that are homozygous for the targeted mutation are viable and fertile. No gene product (mRNA or protein) is detected by Northern or Western blot analysis of inner ear, spleen, and uterine luminal epithelium (Northern), uterus (Western) from homozygotes. On the congenic CBA/CaJ background, homozygotes, 21 months of age, display hearing deficits with loss of auditory brain stem response.
After bacterial infection challenge, homozygotes on the congenic C57BL/6 background have higher bacterial loads, lower secreted cytokine levels in bronchoalveolar lavage fluid, and reduced survival when compared to wildtype controls.
A targeting vector containing IRES-lacZ sequence and a loxP site-flanked PGK-Neo selection cassette was utilized in the construction of this mutant. This selection cassette was inserted into exon 12 of the targeted gene, and another loxP site was inserted upstream of exon 7. The construct was electroporated into 129S1/Sv-Oca2+ Tyr+ Kitl+ derived W9.5 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric animals were tested for germline transmission. To excise the floxed exons 7-11 and part of exon 12, the mice were crossed to Cre deleter mice, expressing cre recombinase directed by the beta actin promoter. The mice were then backcrossed to C57BL/6NCrl for 10 generations.
Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6NJ (Stock No. 005304) at least once to establish the colony.
|Allele Name||targeted mutation 1.1, Colin L Stewart|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Coch, cochlin|
|Strain of Origin||129S1/Sv-Oca2+ Tyr+ Kitl+|
|Molecular Note||Exons 7-11 and part of exon 12, encoding the two vWA domains and remaining cochlin protein downstream of the LCCL domain, were removed via cre mediated recombination. Neither full length or truncated transcripts were detected in mutants.|
|Mutations Made By|| |
Cynthia Morton, Brigham & Women's Hosp. , Harvard Med
When maintaining a live colony, these mice can be bred as homozygotes.
When using the B6.129S1(Cg)-Cochtm1.1Stw/YuanJ mouse strain in a publication, please cite the originating article(s) and include JAX stock #024691 in your Materials and Methods section.