Hippocampus
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S100A6 (calcyclin), an EF-hand calcium binding protein, is considered to play various roles in the brain, for example, cell proliferation and differentiation, calcium homeostasis, and neuronal degeneration. In addition to some limbic nuclei, S100A6 is distributed in the rostral migratory stream, one of the major neurogenic niches of the adult brain. However, the potential involvement of S100A6 in adult neurogenesis remains unclear. ⋯ Cell fate-tracing experiment using BrdU showed that the majority of newly generated immature astrocytes were immunoreactive for S100A6, while mature astrocytes lacked S100A6 immunoreactivity. Administration of S100 protein inhibitor, trifluoperazine, caused a reduction in production of S100β+ astrocyte lineage cells, but had no impact on neurogenesis. Overall, our data provide the first evidence that S100A6 is a specific marker of neural stem cells and astrocyte precursors, and may be especially important for generation of astrocytes in the adult hippocampus.