Essential function of LIF receptor in motor neurons.

Development and maintenance of the mammalian nervous system is dependent upon neurotrophic cytokines. One class of neurotrophic factor acts through receptor complexes involving the low-affinity leukaemia inhibitory factor receptor subunit (LIF-R). Members of this family of cytokines, such as ciliary neurotrophic factor (CNTF) and leukaemia inhibitory factor (LIF), have profound effects on the survival and maintenance of motor neurons. Recently it was reported that mice lacking LIF-R die shortly after birth unlike mice lacking CNTF or LIF which are viable. Here we describe histopathological analyses of lifr mutants that reveal a loss > 35% of facial motor neurons, 40% of spinal motor neurons and 50% of neurons in the nucleus ambiguus. These findings point to the existence of a ligand for LIF-R that is required for the normal development of motor neurons in both brainstem nuclei and spinal cord.