Hiroyuki Okuno

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Arc/Arg3.1 is an immediate-early gene whose mRNA is rapidly transcribed and targeted to dendrites of neurons as they engage in information processing and storage. Moreover, Arc/Arg3.1 is known to be required for durable forms of synaptic plasticity and learning. Despite these intriguing links to plasticity, Arc/Arg3.1's molecular function remains enigmatic.(More)
When new learning occurs against the background of established prior knowledge, relevant new information can be assimilated into a schema and thereby expand the knowledge base. An animal model of this important component of memory consolidation reveals that systems memory consolidation can be very fast. In experiments with rats, we found that the(More)
The neuronal immediate early gene Arc/Arg-3.1 is widely used as one of the most reliable molecular markers for intense synaptic activity in vivo. However, the cis-acting elements responsible for such stringent activity dependence have not been firmly identified. Here we combined luciferase reporter assays in cultured cortical neurons and comparative genome(More)
Long lasting forms of synaptic plasticity and long-term memory formation require new mRNA and protein synthesis. While activity-dependent expression of immediate-early genes has long been thought to account for such critical de novo macromolecular synthesis, experimental proof has been scarce until recently. During the past few decades, a growing number of(More)
The Arc/Arg3.1 gene product is rapidly upregulated by strong synaptic activity and critically contributes to weakening synapses by promoting AMPA-R endocytosis. However, how activity-induced Arc is redistributed and determines the synapses to be weakened remains unclear. Here, we show targeting of Arc to inactive synapses via a high-affinity interaction(More)
Weakly tetanized synapses in area CA1 of the hippocampus that ordinarily display long-term potentiation lasting approximately 3 h (called early-LTP) will maintain a longer-lasting change in efficacy (late-LTP) if the weak tetanization occurs shortly before or after strong tetanization of an independent, but convergent, set of synapses in CA1. The synaptic(More)
Fra-2, one of the Fos-related antigens, is promptly expressed after the growth stimulation of fibroblasts, but its induction peak is later than that of c-Fos. In this report, we examined biochemical properties of Fra-2 and compared them with those of two other Fos family proteins, c-Fos and Fra-1. Like c-Fos and Fra-1, Fra-2 formed stable heterodimers with(More)
Genetic labeling of neurons with a specific response feature is an emerging technology for precise dissection of brain circuits that are functionally heterogeneous at the single-cell level. While immediate early gene mapping has been widely used for decades to identify brain regions which are activated by external stimuli, recent characterization of the(More)
Ca(2+) signaling plays a central role in activity-dependent regulation of dendritic arborization, but key molecular mechanisms downstream of calcium elevation remain poorly understood. Here we show that the C-terminal region of the Ca(2+)/calmodulin-dependent protein kinase CLICK-III (CL3)/CaMKIgamma, a membrane-anchored CaMK, was uniquely modified by two(More)
Identifying the neuronal ensembles that respond to specific stimuli and mapping their projection patterns in living animals are fundamental challenges in neuroscience. To this end, we engineered a synthetic promoter, the enhanced synaptic activity-responsive element (E-SARE), that drives neuronal activity-dependent gene expression more potently than other(More)