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GENE EXPRESSION PROFILES IN THE DEVELOPING RAT CEREBELLUM AND HIPPOCAMPUS
Citation:
KODAVANTI, PRASADA RAO S. AND J. E. ROYLAND. GENE EXPRESSION PROFILES IN THE DEVELOPING RAT CEREBELLUM AND HIPPOCAMPUS. Presented at American Society for Neurochemistry, Madison, WI, June 25 - 29, 2005.
Description:
Development of the nervous system is a complex program, involving coordinated growth of axons and their targets. In rodents, rapid brain growth occurs during early postnatal development. At this time, several fundamental processes, such as dendritic and axonal outgrowth and the establishment of neural connections, occur. Simultaneously, animals acquire many new motor and sensory abilities. In this study, we compare the steady state genomic expression profiles in the hippocampus (Hip) and cerebellum (Cb) during the rapid brain growth period. RNA was extracted from male Long-Evans rat brains on postnatal days (PNDs) 7 and 14. Gene expression was determined on Affymetrix rat 230A chips containing 15,923 genes. Preliminary analysis shows that ~3500 and 4000 genes are e1.5 fold differentially expressed between the Hip and Cb at PND7 and 14, respectively, with ~2300 genes in common to both ages. Expression levels of ~ 2100 genes in the cerebellum and ~1600 genes in the hippocampus are changed by >1.5 fold from PND7 to 14. Of those genes, 680 were common to both brain regions. Interestingly 9 of the 10 top genes upregulated from PND7 to 14 in both the Cb and Hip were related to myelination. This correlates well with the rapid increase in myelin known to occur during the brain growth spurt. Genes down regulated dealt with neuronal migration and axon outgrowth (e.g. cerebroglycan, retinoic acid binding protein), suggesting these processes were largely complete by PND14. Data indicate that 1) differences in gene profiles are greater due to brain area than developmental age based on number of affected genes, 2) gene profiles do reflect changes during brain development and 3) careful baseline studies are necessary for accurate interpretation of genomic data. (The abstract does not necessarily reflect USEPA policy).