To clarify the mechanism of cerebellar development, we have cloned a gene, named zic, encoding a zinc finger protein that is expressed abundantly in granule cells throughout development of the cerebellum. zic has a significant homology to the zinc finger domain of the Caenorhabditis elegans tra1 gene, the Drosophila cubitus interruptus Dominant gene, and the human GLI oncogene. An in situ hybridization study revealed that zic showed a restricted expression pattern in the granule cells and their putative precursor cells. It is also expressed at an early embryonic stage in the dorsal half of the neural tube. The expression pattern and nuclear localization were confirmed by immunohistochemical study. Furthermore, the bacterially expressed zic protein containing the zinc finger domains bound to the GLI-binding sequence. These findings suggest that zic is one of a number of nuclear factors involved in both differentiation in early development and maintenance of properties of the cerebellar granule cells.