Frataxin mitochondrial protein, which is encoded by the Fxn gene, regulates mitochondrial iron transport and respiration. Expansion of the intronic GAA nucleotide repeat causes Friedreich's ataxia. These Frdadel4 mice carry a knock out mutation for the Fxn gene in which exon 4 has been replaced by a floxed PGK-NEO cassette. Mice that are heterozygous for the targeted mutation are viable and fertile.
No gene product (protein) is detected by Western blot analysis of rescued double mutant mice that are homozygous for this null allele and are carrying the Tg(FXN)Y47Pook transgene (see Stock#024097).
Homozygous null mice have an early post-implantation lethal phenotype, and are resorbed by E9.5. By E7, homozygous embryos and extra-embryonic tissues are smaller in size than wildtype controls. At E6.75 and E7.5, homozygous embryos exhibit pycnotic nuclei and condensed chromatin; extra-embryonic regions exhibit clusters of apoptotic TUNEL-positive cells. Necrotic cells are also observed.
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. This is the case for the strain above. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.
Importation of this model was supported by the Friedreich's Ataxia Research Alliance (FARA).
