Neural cell adhesion molecules (NCAMs) are of pivotal importance for neurons to navigate within the brain and to recognize a defined set of synaptic partners in order to establish the neural circuits that a brain requires to fulfill its complex tasks. The functional disruption of NCAMs has substantial effects on the development and function of the brain and is the underlying cause for several neurological syndromes. To investigate this activity, an identification was performed of a novel subfamily of immunoglobulin superfamily members, the zig genes, which are predicted to code for cell surface adhesion molecules. Expression pattern analysis has revealed that most of these genes are expressed in specific domains of the nervous system suggesting that ZIG proteins indeed function as neural adhesion molecules that are involved selective cell-cell adhesion events to establish neural circuitries in the nervous system. We will characterize three selected members of this gene family, zig-2, zig-3, zig-4, which we found to be expressed in a specific subset of neurons. Characterization of these genes will include: an analysis of the temporal and spatial patterns of ZIG-2/3/4 proteins; use reverse genetic approaches to isolate mutant animals in which these genes have been deleted and characterize the functional consequence of the respective gene deletion; define zig phenotypes on a single cell level and attempt to correlate them to the defined set of behavioral tasks that C. elegans is able to perform; define genes that functionally interact with specific zig genes using genetic approaches.