The close homologue of the neural adhesion molecule L1 (CHL1): patterns of expression and promotion of neurite outgrowth by heterophilic interactions.

The close homologue of L1 (CHL1), a member of the L1 family of neural adhesion molecules, is first expressed at times of neurite outgrowth during brain development, and is detectable in subpopulations of neurons, astrocytes, oligodendrocyte precursors and Schwann cells of the mouse and rat. Aggregation assays with CHL1-transfected cells show that CHL1 does not promote homophilic adhesion or does it mediate heterophilic adhesion with L1. CHL1 promotes neurite outgrowth by hippocampal and small cerebellar neurons in substrate-bound and soluble form. The observation that CHL1 and L1 show overlapping, but also distinct patterns of synthesis in neurons and glia, suggests differential effects of L1-like molecules on neurite outgrowth.