We previously reported the results of our gene expression profiling analysis of embryonic mouse brains utilizing the Affymetrix GeneChip (SFN Annual Meeting, 2001). We recently identified a novel protein kinase gene by in silico and experimental cDNA cloning of differentially expressed gene candidates obtained by the GeneChip analysis, and designated as Ebr kinase (embryonic brain kinase). The Ebr kinase gene encodes 435 amino acids and contains Ser/Thr protein kinase domain. To confirm the temporal developmental expression profiles of Ebr kinase gene, we subjected it to a more reliable, real time quantitative RT-PCR analysis using the TaqMan system. The data obtained by both GeneChip and TaqMan PCR methods showed almost parallel down-regulation profile. We investigated the activity of Ebr kinase was investigated by in vitro kinase assay using GST fusion proteins of wild type and kinase domain mutants, and indicated that the wild type had kinase activity whereas the mutants did not it. Next, we examined th...