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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID
Tg(FXN)YG22Pook
transgene insertion YG22, Mark A Pook
MGI:4412181
Summary 2 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
cx1
Fxntm1Mkn/Fxntm1Mkn
Tg(FXN)YG22Pook/0
involves: 129/Sv * C57BL/6 * CBA MGI:5700053
tg2
Tg(FXN)YG22Pook/0 B6J.Cg-Tg(FXN)YG22Pook MGI:5700052


Genotype
MGI:5700053
cx1
Allelic
Composition
Fxntm1Mkn/Fxntm1Mkn
Tg(FXN)YG22Pook/0
Genetic
Background
involves: 129/Sv * C57BL/6 * CBA
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fxntm1Mkn mutation (13 available); any Fxn mutation (33 available)
Tg(FXN)YG22Pook mutation (2 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
N
• embryonic lethality seen for Fxn-deficient embryos is recued by transgene expression; normal numbers of offspring are recovered and mice show normal lifespans, surviving to at least 2 years of age

growth/size/body
• significant increase is observed from 6 months of age
• increase in weight from 6 months of age

nervous system
N
• no neuronal histopathology is detected in cerebellar Purkinje cells or granule cells, and no abnormalities in brain or spinal cord regions are seen
• no sensory nerve or motor nerve conduction changes are seen in 9-14 month old mutants
• peripheral margination of the nucleus in many large neuronal cell bodies of the dorsal root ganglia, suggesting central chromatolysis
• between 6 months to 1 year, vacuoles are seen only in the dorsal root ganglia of the lumbar region, but after 1 year, vacuoles are seen within dorsal root ganglia of the cervical region, indicating a distal-to-proximal dying back neurodegeneration
• prominent, giant vacuoles (round, singular or multiple) are observed in large sensory neuronal bodies of dorsal root ganglia; peripheral margination of nucleus in many large neuronal cell bodies with or without vacuoles

behavior/neurological
• reduced performance on an accelerating rotarod from 3 months of age
• however, overt ataxia is not seen up to 2 years of age
• forelimb grip strength is decreased from 9 months of age
• mice show a decreased trend in locomotor activity in the open field from 6 months of age and a significant difference by 1 year of age

cardiovascular system
• iron deposition within the heart of 14-18 month old mice
• however, mice do not exhibit an increase in heart weight to body weight ratio, myofibril disarray, or fibrosis

cellular
• in 6-9 month old mice, oxidized proteins are increased in the cerebrum, cerebellum, heart, and skeletal muscle, with the most prominent increase in the cerebrum and cerebellum
• increase in lipid peroxidation in the heart

homeostasis/metabolism
• iron deposition within the heart of 14-18 month old mice
• however, mice do not exhibit an increase in heart weight to body weight ratio, myofibril disarray, or fibrosis
• level of the antioxidant enzyme CuZnSOD is decreased in the skeletal muscle by 40%

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
Friedreich ataxia DOID:12705 J:114840




Genotype
MGI:5700052
tg2
Allelic
Composition
Tg(FXN)YG22Pook/0
Genetic
Background
B6J.Cg-Tg(FXN)YG22Pook
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Tg(FXN)YG22Pook mutation (2 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
cellular
• mice show intergenerational instability of the GAA repeat sequence during transmission from parents to offspring through five to 8 generations
• F1 generation offspring do not display changes, but from the F2 generation onward, expansions or contractions are observed, increasing in size with subsequent backcrosses
• discreet bimodal expansions of the 190-GAA repeat units are observed in the F6-F7 generations onward; large hyperexpansions as seen in human samples are not detected
• somatic instability is age-related, with very little or no instability observed at 2 months, but at 9 and 12 months, smears of expanding GAA repeats are detected in cerebellar hemisphere, brain stem and cerebellum tissue
• 6-month old mice show repeat instability in CNS tissues, but not significantly greater than observed at 3 months
• instability is influenced by sex of transgenic parent, with overall bias toward intergenerational repeat contraction upon maternal transmission of transgene
• a parental age-related effect of GAA repeat instability is seen, with a bias towards expansions in offspring from male parents over 7 months of age





Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB), Gene Ontology (GO)
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last database update
01/12/2022
MGI 6.17
The Jackson Laboratory