MURINE CEREBELLAR NEURONS EXPRESS A NOVEL GENE ENCODING A PROTEIN RELATED TO CELL-CYCLE CONTROL AND CELL FATE DETERMINATION PROTEINS

We cloned cDNAs of a novel protein (designated V-1) that has been iden tified from among the developmentally regulated proteins in the rat ce rebellum. Protein sequencing analysis (Taoka, M., Yamakuni, T., Song, S.-Y., Yamakawa, Y., Seta, K., Okuyama, T., and Isobe, T. (1992) Eur. J. Biochem. 207, 615-620) and cDNA sequence analysis revealed that the V-1 protein consists of 117 amino acids and contains 2.5 contiguous r epeats of the cdc10/SWI6 motif, which was originally found in the prod ucts of the cell cycle control genes of yeasts and the cell fate deter mination genes in Drosophila and Caenorhabditis elegans. In situ hybri dization histochemistry revealed that the expression of the V-1 gene i s transiently increased in postmigratory granule cells during postnata l rat cerebellar development and thereafter is markedly suppressed, wh ereas Purkinje cells constitutively express V-1 mRNA. In contrast, cer ebellar granule cells of the staggerer mutant mouse continue to expres s the V-1 gene even when the granule cells of the normal mouse have ce ased to express the V-1 gene, suggesting that the expression of the V- 1 gene in granule cells is regulated through the interaction with Purk inje cells. On the basis of these results, we postulate that the V-1 p rotein has a potential role in the differentiation of granule cells.