This Car5b knockout strain is useful in studies of mitochondrial oxidative stress, ureagenesis (ammonia detoxification), gluconeogenesis and lipogenesis. This targeted mutation is X-linked.
William S Sly, Saint Louis University Medical Center
The X-linked Car5b gene is ubiquitously expressed outside the liver, especially in kidney and encodes for mitochondrial carbonic anhydrase 5b, a zinc metalloenzyme that catalyze the reversible hydration of carbon dioxide (to carbonic acid).
Carbonic anhydrase 5b is involved in ureagenesis (ammonia detoxification) and, gluconeogenesis and may be involved in lipogenesis and mitochondrial oxidative stress. These mice carry a knock out mutation for the Car5b gene, in which exon 3 has been excised. Exon 3 encodes for 2 of the 3 zinc binding histidine residues and the mutation creates a frameshift at exon 4. No gene product (mRNA) is detected by RT-PCR of liver and kidney tissue from homozygous animals. Homozygotes are viable and fertile with no overt abnormal phenotype.
When bred to Car5a knockout mice (Stock No. 025331), the resulting double mutants have a more severe phenotype than the single mutant Car5a knockout mice, and die shortly after weaning. However, the double mutants exhibit reduced evidence of oxidative stress in the brain.
A targeting vector containing a loxP flanked neomycin-Cre recombinase self excising ACE cassette (angiotensin converting enzyme) was used to disrupt exon 3 of the X-linked Car5b gene. The construct was electroporated into 129S1/Sv-Oca2+ Tyr+ Kitl+ derived W9.5 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were bred to C57BL/6 mice.
Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.
|Allele Name||targeted mutation 1, William S Sly|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Car5b, carbonic anhydrase 5b, mitochondrial|
|Strain of Origin||129S1/Sv-Oca2+ Tyr+ Kitl+|
|Molecular Note||Thirty bp (codons for 10 amino acids) in exon 3 were replaced with a floxed cassette composed of a neomycin resistance gene and cre placed under the direction of a testis specific angiotensin converting enzyme pomoter. Cre expression in the germline of chimeric male mice excised the inserted cassette leaving a deletion in exon 3 including two of three zinc binding histidine residues and introducing a frameshift beginning in exon 4. A stop codon was created after 11 missence amino acids.|
When maintaining a live colony, these mice can be bred as homozygotes. This targeted mutation is X-linked.
When using the Car5B KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #025570 in your Materials and Methods section.