NEUROTROPHIC FACTORS AND THEIR RECEPTORS - IMPLICATIONS OF GENETIC-STUDIES

The genes encoding each of the known neurotrophins and their receptors have been targeted in mice. As predicted by earlier studies, each mut ation results in loss of specific classes Of peripheral neurons. Apopt osis during the period of naturally occurring cell death appears to be responsible for many of these losses. In some cases, deficits may ref lect earlier abnormalities in precursor proliferation, commitment or d ifferentiation. Specific examples of abnormal target innervation and n euronal differentiation have been observed in these mutants, which are beginning to be used to address other Postulated functions of neurotr ophins, such as modulation of synaptic efficacy and plasticity.