The 14-3-3 protein family is known to interact with various proteins involved in signaling pathways. We report here the expression pattern of the Drosophila 14-3-3 (d14-3-3epsilon) protein during embryonic development. In syncytial blastoderm when the nuclei divided rapidly, d14-3-3epsilon localized in the nuclei. During cellularization d14-3-3epsilon gradually became membrane-bound. During gastrulation, an enhanced staining in the perinuclear region was observed in various tissues. Co-labeling with dp-ERK which recognized the activated form of MAPK suggested that d14-3-3epsilon was expressed prior to MAPK activation. During neuronal differentiation, the d14-3-3epsilon protein remained at a high level in the neuronal cytoplasm.