THE MOUSE ZIC GENE FAMILY - HOMOLOGS OF THE DROSOPHILA PAIR-RULE GENEODD-PAIRED

The mouse Zic gene, which encodes a zinc finger protein, is expressed in the developing or matured central nervous system in a highly restri cted manner. We identified two novel Zic-related genes (Zic2, Zic3) th rough genomic and cDNA cloning. Both genes are highly similar to Zic(1 ), especially in their zinc finger motif. A comparison of genomic orga nization among the three Zic genes showed that they share common exon intron boundaries and belong to the same gene family. Zic1, Zic2, and Zic3 were determined to mouse chromosome 9, 14, and X using an intersp ecific backcross panel. Northern blotting and ribonuclease protection showed that Zic2 and Zic3 are expressed in a restricted manner in the cerebellum at the adult stage. However, the temporal profile of the mR NA expression in the developing cerebella differ in the three Zic gene s. Furthermore, we found that the Drosophila pair-rule gene, odd-paire d is highly homologous to the Zic gene family. The similarity was not only the zinc finger motif, but also the exon-intron boundary was the same as those of mouse Zic gene family. These findings suggest that th e Zic gene family and Drosophila odd-paired are derived from a common ancestral gene.