Fig. 1. MTS24 reactivity in mouse epidermis. Formalin-fixed frozen section of C57Bl/6 mouse tail skin (A,B) and Balb/c mouse dorsal skin (C-E) showing MTS24-Cy3 staining (red) in the hair follicle and merged with DAPI (B,D,E; blue) to highlight nuclei. Inset (E) shows that MTS24-staining was found on the membrane of follicular cells. (F,G) Wholemounts from C57Bl/6 mouse tail skin showing MTS24-Alexa 488 labelling (green) within the hair follicle, counterstained with ToPro3 (blue). (H,I) MTS24-Cy3 staining in hairless SKH-1 mouse dorsal skin and merged with DAPI (I). The asterisk marks the smear-like appearance of MTS24 within the inner hair shaft. (J) MTS24-Cy3 staining in 2-day-old hairless SKH-1 mouse dorsal skin. The green staining of the hair was caused by autofluorescence. (K-N) Immunoelectronmicroscopic pictures of MTS24-labelling. (M) Cross-sectional overview of murine hair follicle from 2-day-old SKH-1 mouse dorsal skin. K,L,N are higher magnifications of certain regions (indicated by the arrow) within M. (K,M) Active cycling cells were found in the outer root sheath (ORS, asterisks). Within the inner root sheath (IRS), apoptotic cells were found (L,M; crosshatches). Detail (K) of the ORS showing three neighbouring cells (cells 1-3). MTS24 was found on the cell membrane of these cells (arrowheads). (L) Apoptotic cell (crosshatch) within the IRS. MTS24 was found on the cell membrane (arrowheads). (N) Membranes of dead cells within the IRS positive for MTS24 (arrowheads). SG, sebaceous gland; HF, hair follicle; IFE, interfollicular epidermis; BG; bulge, HS, hair shaft. Scale bars: 50 µm (in A,B,F,G), 25 µm (in C,D,H-J), 10 µm (in E) and 1 µm (in K-N).