The DDAH1flox allele has loxP sites flanking exon 4 of the dimethylarginine dimethylaminohydrolase 1 gene. Removal of the floxed sequence creates a null allele. These mice may be used to manipulate DDAH1 expression for studying methylarginine (ADMA and L-NMMA) accumulation and systemic nitric oxide bio-availability in several disorders, including cardiovascular disease and diabetes.
Yingjie Chen, University of Minnesota
The DDAH1flox allele has loxP sites flanking exon 4 of the dimethylarginine dimethylaminohydrolase 1 gene (Ddah). DDAH1 functions to remove/degrade endogenous nitric oxide synthase inhibitors, such as asymmetrical dimethylarginine [ADMA] and L-NMMA, from plasma and tissues.
Homozygous floxed mice (DDAH1flox/flox) exhibit no significant differences in DDAH1 protein level, left ventricle function, blood pressure, heart rate, and heart weight:body weight ratio compared to wildtype mice. Homozygous floxed mice are viable and fertile.
When DDAH1flox mice are bred to Cre recombinase expressing mice, the resulting offspring will have the floxed exon deleted in the cre-expressing tissues. Homozygous deletion of exon 4 creates a null allele.
Both global DDAH1 deletion (DDAH1-/-) or vascular endothelium-specific DDAH1 deletion (endo-DDDAH1-/-) cause increased accumulation of methylarginines (ADMA and L-NMMA), inhibition of nitric oxide synthase (NOS) function/production of nitric oxide (NO), abnormal cardiovascular physiology (hypertension, mild ventricular hypertrophy) and endothelial dysfunction.
These mice may be useful in studying cardiovascular disease, hypertension, coronary artery disease, thrombosis, stroke, congestive heart failure, atherosclerosis, hypercholesterolemia, insulin resistance, diabetes mellitus, type 2 diabetes, idiopathic pulmonary fibrosis, neuronal or behavioral changes, and tumor angiogenesis.
The DDAH1flox allele was designed by Dr. Yingjie Chen (University of Minnesota) to have a loxP site upstream of exon 4, and a second loxP site followed by a frt-flanked neo cassette just downstream of exon 4 of the dimethylarginine dimethylaminohydrolase 1 gene. The targeting construct was electroporated into 129S1/Sv-Oca2+ Tyr+ Kitl+-derived CJ7 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts, and chimeric males were bred with C57BL/6J females to establish the colony. The resulting DDAH1flox mice were bred with C57BL/6J wildtype mice for at least nine generations prior to sending males with black coat color to The Jackson Laboratory Repository in 2015. Upon arrival, sperm was cryopreserved. To establish our live colony, frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
|Allele Name||targeted mutation 1, Yingjie Chen|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Ddah1, dimethylarginine dimethylaminohydrolase 1|
|Strain of Origin||129S1/Sv-Oca2+ Tyr+ Kitl+|
|Molecular Note||Exon 4 was flanked by loxP sites and an FRT flanked neomycin selection cassette was inserted immediately downstream of the loxP site in intron 4.|
When maintaining a live colony, mice homozygous for the floxed allele may be bred together.
When using the DDAH1flox mouse strain in a publication, please cite the originating article(s) and include JAX stock #026756 in your Materials and Methods section.