In this mouse, Exons 2-5 of the (silent information regulator 2 (Sir2)) homolog 5, Sirt5, gene is replaced with a β-galactosidase (lacZ) cassette, abolishing gene function. These mice may be useful in studies related to life span and the effects of food restriction on ammonia detoxification and disposal though CPS1 activation.
Dr. Frederick W. Alt, Children's Hospital
The targeted mutation replaces exon 2-5 of the mouse sirtuin (silent information regulator 2 (Sir2)) homolog 5, Sirt5, gene with a β-galactosidase (lacZ) cassette, abolishing gene function. In these mice lacZ expression is driven by the Sirt5 endogenous promoter and is detected in the mitochondrial matrix. Homozygous mice are viable, fertile, and normal in size. Sirt5-/- mice show elevated blood ammonia levels after fasting (48 hours) due to inactivation of carbamoyl phosphate sythetase 1 (CPS1), a Sirt5-specific substrate. These mice may be useful in studying life span and the effects of sirtuin and food restriction on ammonia detoxification and disposal though CPS1 activation.
A targeting vector was designed to replace exon 2-5 of the mouse sirtuin (silent information regulator 2 (Sir2)) homolog 5, Sirt5, gene with a β-galactosidase (lacZ) cassette. This construct was electroporated into 129S1/Sv-derived CJ7 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6J blastocysts. The resulting chimeric males were bred to 129Sv females and the resulting heterozygous offspring were intercrossed to produce a colony of homozygous Sirt5-/- mice (see SNP results below). Homozygous males with agouti coat color were sent to The Jackson Laboratory Repository in 2012. Upon arrival, males were used to cryopreserve sperm. To establish the living mouse colony, an aliquot of the frozen sperm was used to fertilize 129S1/SvImJ oocytes (Stock No. 002448).
A 32 SNP (single nucleotide polymorphism) panel analysis, with 32 markers covering all 19 chromosomes and the X chromosome, was performed on the first generation rederived living colony at The Jackson Laboratory Repository. This revealed 5 of 32 markers, one each on chromosomes 1, 3, 4, 12 and 20, that were not fixed for 129 allele-type (e.g., still segregating for C57BL/6 allele-type markers). These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed 129;C57BL/6 genetic background, and are now a mix of 129 (~85%) and C57BL/6 (~15%).
|Allele Name||targeted mutation 1, Frederick W Alt|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Sirt5, sirtuin 5|
|Site of Expression||lacZ is expressed in the mitochondrial matrix.|
|Strain of Origin||129S1/Sv-Oca2+ Tyr+ Kitl+|
|Molecular Note||Exons 2 through 5 were replaced with a lacZ gene inserted in frame after the 23rd base pair of exon 2. The absence of protein product was confirmed by western blot analysis on liver extracts.|
|Mutations Made By|| |
Dr. Frederick Alt, Children's Hospital
When maintaining a live colony, homozygous mice may be bred together.
When using the Sirt5 KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #012757 in your Materials and Methods section.