ABSTRACT
The hypothesis that factors from developing muscle play a central role in regulation of motor neuron survival during development has recently been challenged by observations that other types of cell, in particular Schwann cells, are also important in this context. Neuregulin/glial growth factor (GGF) is also synthesized and secreted from developing motor neurons. A variety of gene defects, in particular mutations in the superoxide dismutase (SOD1), akin, senataxin and vesicle-associated membrane protein (VAPB) genes, have been identified and characterized, and underlie the inherited forms of amyotrophic lateral sclerosis (ALS) and other forms of motor neuron disease in the adult and regulates the expression of acetylcholine receptor subunits at the motor end-plate. Ciliary Neurotrophic Factor (CNTF) was originally identified and characterized as a component of chick eye extracts, and found to share many biologic activities with a protein that was purified from rat sciatic nerve.
