TRACT FORMATION AND AXON FASCICULATION OF MOLECULARLY DISTINCT PERIPHERAL NEURON SUBPOPULATIONS DURING LEECH EMBRYOGENESIS
Kristen M. Johansen, Diane M. Kopp, John Jellies, and Jørgen Johansen
In leech, the central projections of peripheral sensory neurons segregate into specific axonal tracts, which are distinguished by differential expression of surface antigens recognized by the monoclonal antibodies lan 3-2 and lan 4-2. Lan 3-2 recognizes an epitope expressed on axons which segregate into three distinct axon fascicles. In contrast, the lan 4-2 positive axons selectively project into only one of the lan 3-2 positive axon tracts. These observations provide evidence for a hierarchy of guidance cues mediating specific pathway formation in this system. Since the lan 3-2 antibody has been shown to perturb this process (Zipser et al., Neuron 3, 621) and since as shown here the lan 3-2 and lan 4-2 antigens are closely molecularly interrelated, these antibodies may help define molecules and epitopes mediating neuronal recognition and axonal guidance.