Delineating developmental and metabolic pathways in vivo by expression profiling using the RIKEN set of 18,816 full-length enriched mouse cDNA arrays

We have systematically characterized gene expression patterns in 49 adult a nd embryonic mouse tissues by using cDNA microarrays with 18,816 mouse cDNA s. Cluster analysis defined sets of genes that were expressed ubiquitously or in similar groups of tissues such as digestive organs and muscle. Cluste ring of expression profiles was observed in embryonic brain, postnatal cere bellum, and adult olfactory bulb, reflecting similarities in neurogenesis a nd remodeling. Finally, clustering genes coding for known enzymes into 78 m etabolic pathways revealed a surprising coordination of expression within e ach pathway among different tissues. On the other hand, a more detailed exa mination of glycolysis revealed tissue-specific differences in profiles of key regulatory enzymes. Thus, by surveying global gene expression by using microarrays with a large number of elements, we provide insights into the c ommonality and diversity of pathways responsible for the development and ma intenance of the mammalian body plan.