mortality/aging
• about half die at the time of weaning, P21
|
• 10-20% of mutants survive to adulthood (>3 months)
|
• about 2/3 of mice that survive to weaning die over the next few weeks
|
behavior/neurological
• mutants develop a tremor when moving, starting at P5, that persists throughout life
|
growth/size/body
• mutants grow slower than control littermates and fail to thrive, although the remain active and responsive
|
nervous system
• mutants lack asymmetric acetylcholinesterase in skeletal neuromuscular junction synapses and in the heart and brain and the asymmetric forms of the acetylcholinesterase homologue, butyrylcholinesterase
• mutants lack globular acetylcholinesterase in skeletal muscle
• neuromuscular junction synapse structure is abnormal; approximately 40% of synaptic sites are smaller but normal in appearance, 20% remain immature, and 40% appear fragmented
• cytoplasm beneath the postsynaptic membrane often has holes, indicating localized subsynaptic necrosis; incidence is higher at P20 (2/3 of synapses show necrosis) than at 6 months (less than 5% show necrosis)
• nerve terminals sometimes are partially enwrapped by processes of Schwann cells; incidence is higher at 6 months of age (more than half) than at P20 (1/3)
|