Fig. 1: Tanycytes in ME are slow-cycling cells.

a Representative image of fluorescent immunoreactivity in adult coronal brain sections from GFAP-CreER^T2::Ai14 mice. White box indicates the magnified view of the median eminence (ME) on the right. The mice were induced with tamoxifen at postnatal day 60 (P60) and sacrificed at 7 days post induction (dpi) to guide microdissection of ME. Scale bars: 1000 µm (left) and 50 µm (right). b Spectral t-distributed stochastic neighbor embedding (tSNE) representation of the single-cell transcriptomic data with clusters colored and annotated according to known cell-type markers. PTCs pars tuberalis cells, VLMCs vascular and leptomeningeal cells, OPCs oligodendrocyte precursor cells, NKCs natural killer cells, MGs microglia, ODs oligodendrocytes. c tSNE scatter plots covering neural cell clusters show the specific expression of Rax, Col25a1, Scn7a and Mia in tanycytes. d Representative images of smFISH probing for Rax mRNA display no colocalization of EdU with Rax. Numbers refer to subregions shown in the magnified images (right). Yellow arrowheads indicate Rax⁺ tanycytes and dashed white circles signify EdU⁺ mitotic cells. EZ ependymal zone, SEZ subependymal zone. Scale bar: 40 µm (left) and 10 µm (right). e, f Shown are Scn7a and Col25a1 gene expression in ME detected by smFISH and three-dimensional (3D) simulation of Scn7a- and Col25a1-positive signals. Scale bars: 50 µm. g Representative images stained for EdU with multiple cell markers including Sox2, NG2, Olig2, NeuN, CC1, S100β, and Iba1. Three daily EdU administrations were applied to label dividing cells. Scale bars: 10 µm. h Quantification of the percentage of different cell types among mitotic cells. Values represent mean ± SEM (n = 7, 7, 7, 3, 3, 4, 3, 4, and 4 mice from bottom to top bars).