IDENTIFICATION AND CHARACTERIZATION OF ZIC4, A NEW MEMBER OF THE MOUSE ZIC GENE FAMILY

The mouse Zic genes encode zinc-finger (Zf) proteins expressed only in the cerebellum of the adult brain. The genes are the vertebrate homol ogues of the Drosophila pair-rule gene, odd-paired (opa). We identifie d a novel gene, Zic4, which belongs to the Zic gene family, through a genomic and cDNA cloning study. Zic4 is highly similar to Zic1, Zic2 a nd Zic3, especially in its Zf motif. An analysis of the genomic organi zation of Zic4 showed that the gene shares a common exon-intron bounda ry with Zic1, Zic2, Zic3 and opa. The chromosomal location of Zic4 was determined to be mouse chromosome 9 in the vicinity of Zic1, using an interspecific backcross panel. An RNase protection study showed that Zic4 is expressed only in the cerebellum during the adult stage, as ar e the other Zic genes. The temporal profile of mRNA expression in the developing cerebellum is similar to that of Zic3 which has a peak on p ostnatal day 5. These findings suggest that Zic4 is a gene which works cooperatively with other Zic genes during cerebellar development.