MsrA (methionine sulfoxide reductase A) knock-out mice exhibit enhanced sensitivity to oxidative stress.
Rod Levine, NIH-NHLB
Geumsoo Kim, LB/NHLBI/NIH
The Msra (methionine sulfoxide reductase A) gene encodes an enzyme involved in the reduction of methionine sulfoxide to methionine and functions as a regulator of antioxidant defense by scavenging intracellular reactive oxygen species (ROS). MsrA knock-out mice contain a neomycin cassette inserted into exon 2 (containing active site of the protein). Mice that are homozygous for the targeted mutation are viable and fertile with no overt phenotype. Mice exhibit enhanced sensitivity to oxidative stress (100% oxygen) including higher tissue levels of oxidized protein (carbonyl derivative) in liver, kidney and lung (and to a lesser extent in brain) and a decreased ability to up-regulate expression of thioredoxin reductase in the brain and liver. These mice may be useful for studying oxidative stress.
The targeting vector is designed to replace the coding sequence in exon 2 (amino acids 69-109 of the protein containing the active site) with a neomycin resistance cassette. The construct was electroporated into 129X1/SvJ-derived RW4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric animals were crossed to C57BL/6J for germline transmission. The strain was backcrossed to C57BL/6NJ for at least 10 generations. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6NJ oocytes.
|Allele Name||targeted mutation 1, Jackob Moskovitz|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||MsrA-; MsrA1-|
|Gene Symbol and Name||Msra, methionine sulfoxide reductase A|
|Strain of Origin||129X1/SvJ|
|Molecular Note||A neomycin cassette was used to disrupt the sequence of exon 2, which encodes the active site of the protein. Western analysis confirmed a lack of protein. The presence of enzymatic activity in tissues from homozygous mutant tissue, indicated the presence of another form of the enzyme.|
When maintaining a live colony, these mice are bred by homozygous sibling matings.
When using the MsrA- mouse strain in a publication, please cite the originating article(s) and include MMRRC stock #50602 in your Materials and Methods section.