Fig. 1

Mechanical activation evokes Ca2+ signals in OLs, with TMEM63A as a key MC (A) Mechanical indentation applied to OL soma. (B) (Left to right) Time-series projection of jGCaMP8s in a cultured OL at baseline and after mechanical stimulation, mScarlet co-expression, and map of calcium microdomains (CaM). (C and D) Color-coded Ca2+ activity map (C) and intensity vs. time traces (D) of six CaMs in OL soma and CaMs. (E) Duration and amplitude (as Z scores) of Ca2+ transients in 158 CaMs. (F and G) Average amplitude (ΔF/F) of Ca2+ events (F) and time to spread from soma to distal processes (G). Pro., processes. (H) Workflow of OL isolation by MACS and FACS and combinatorial barcoding of OLs. (I) Cell clusters identified from scRNA-seq pre-myelinating OLs (pmOLs; 422 cells, orange), newly formed OLs (NFOLs; 375 cells, purple), and mature OLs (MOLs; 244 cells, green). (J and K) Expression of key marker genes (J) and MCs (K) in pmOL, NFOL, and MOL. Dot size: percentage of cells expressing a gene; color code: average expression levels. (L) Wild-type Tmem63a (T63a) and Tmem63a-eYFP knockin (T63a-eYFP) reporter allele, where eYFP cDNA was fused to exon 23. (M–P) Coronal hemi-section of a T63a-eYFP/+ mouse brain at P35 immunostained for eYFP and CNP (M), higher magnification of motor cortex (Cx) and corpus callosum (CC) from boxed area (N), and further zoom-in of Cx (O) and CC (P) to show individual cells. (Q) Proportion of CNP+ OLs co-labeled with eYFP+ cells in Cx and CC. (D and E) Stim: time of stimulation. Data represent mean ± SEM (F and G) and mean % (Q). See also Figures S1 and S2, Video S1, and Table S3 (sample sizes and statistical tests).