Gene expression profiling of mouse postnatal cerebellar development using cDNA microarrays.

The cerebellum serves as a model system for developmental studies of the mammalian nervous system. Classical analysis of individual genes is insufficient to address the complex regulatory circuits underlying the developmental process. In this study, the postnatal cerebellar development of mice aged 2, 4, 8, 12, 16, 21 and 42 days old was studied using a microarray spotted with 5494 cDNA clones collected from the cerebellum and the cerebrum of C57BL/6J mice. We were able to cluster the expression patterns into four groups and each was highly correlated with gene function. Housekeeping genes are in a cluster in which the expression pattern peaks at the neonatal stage, while genes related to brain function peak at the adult stage. The other two clusters, characterized by transiently upregulated or downregulated expression during days 8-16, contain genes with different functions, most notably related to cell differentiation and cell cycle progression. Based on this categorization and on motif scanning, we were able to assign hypothetical functions to functionally undetermined genes. The result indicates that expression profiling is an efficient method for generation of new hypotheses for the developmental study of the cerebellum. When combined with other studies such as pharmacology etc., data generated in this study may have application in the elucidation of genetic networks underlying developmental disorder.