Analysis Tools
mortality/aging
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• began dying in 3rd week post natally and none survived beyond 3 months of age
(J:91702)
• average lifespan is ~62.3 days
(J:115193)
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growth/size/body
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• mice are visibly smaller than littermates at 10 weeks
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weight loss
(
J:115193
)
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• mice exhibit relative loss of body weight after P20 and
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• weight gain stopped around 15 days of age
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behavior/neurological
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• became lethargic around 30 days of age but still at and moved about when stimulated
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• poor acoustic startle reflex
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limb grasping
(
J:91702
)
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• tendancy to clasp hindlimbs when suspended by their tail
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• difficulty righting themselves when place on their side by age 15 days and becoming much worse after 25 days of age
(J:91702)
• after postnatal day 20, mice become increasingly debilitated and require up to 30 seconds to become upright
(J:115193)
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• unable to remain on a turning rod
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• in a grip test, mice cannot grip the mesh for very long before dropping, compared to the 2 minute duration of the test achieved by wild-type mice
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• lack of grip strength
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• in a quantitative assessment of motor behavior, mice usually stay in one sector of the force plate and exhibit jerky movements
(J:115193)
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• lack of spontaneous activity in open field tests
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nervous system
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• at P28, strong activation (gliosis) of Muller glia is detected in ONL
(J:107310)
• gliosis resulting from neurodegeneration is prominent in spinal cord and forebrain
(J:115193)
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• mice show considerable photoreceptor degeneration
(J:115193)
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• neuromuscular junctions with an immature appearance and sometimes lack presynaptic nerve branches
• appearance indicative of degeneration
• defects present at all ages but less at 7 days
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• transmission across the neuromuscular synapse deteriorating by age 20-23 days
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• amplitude of compound muscle action potentials dropped significantly around day 43-47
• increased synaptic depression due to repetitive stimuli by day 15
• rise and decay of excitatory post synaptic currents slower and irregular
• facilitation rather than depression often seen during stimulus trains
• increased amplitude of currents at day 20-23
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vision/eye
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• mice show considerable photoreceptor degeneration
(J:115193)
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• ONL shrinks dramatically with photoreceptor degeneration
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• at P15, presynaptic photoreceptor ribbon terminals are smaller than in wild-type and show an increased synaptic vesicle density; at P28, terminal sizes are heterogeneous, but usually smaller than wild-type, although large swollen terminals are observed with moderate frequency
(J:107310)
• at P28, continuous array of synaptic ribbons in outer plexiform layer (OPL) is disrupted and ectopic ribbons and synaptic proteins are detected in the outer nuclear layer, while membrane attachment of ribbons is decreased; synaptic membrane proteins in OPL are decreased in abundance and nonsynaptic proteins like opsin are mislocalized
(J:107310)
• heterogeneous and pleiomorphic alterations of photoreceptor ribbon synapses such as large decreases in synaptic vesicle density, decrease or loss of the invaginated shape of the presynaptic plasma membrane, formation of electron dense aggregates, detachment or complete loss of synaptic ribbons from presynaptic photoreceptor terminals, are seen at P28
(J:107310)
• OPL disintegrates in mutants
(J:115193)
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• at postnatal day (P)14, a-wave amplitude is reduced to ~40% of littermate controls and exhibits a slower time course; in 4/5 mutants, the b-wave is absent
• at P18, some mice present with a flat electroretinogram (ERG), while the remainder exhibit small and slow a- and b-waves; mice displaying a measurable ERG response have abnormally slow light responses with the time-to-peak of the a-wave ~3x that of control mice
• at P30 and P45, all mutants lack a detectable ERG response
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• on basis of ERG results, mutants initially have some visual function but suffer from a progressive blindness
(J:107310)
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muscle
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• decreased pelvic girdle muscle mass
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• appears by 2-3 weeks of age
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endocrine/exocrine glands
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• bilateral abdominal cryptorchism
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reproductive system
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• bilateral abdominal cryptorchism
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hearing/vestibular/ear
| N |
• mice display normal morphology and function of presynaptic ribbons in inner hair cells
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• at 4 weeks of age, mice show a reduction or loss of otoacoustic emissions
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• at 4 weeks of age, mice show mild hearing impairment of ~30 decibels
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• hearing impairment is presumed to be due in part to a defect in middle ear sound transduction
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