Figure 4.

Embigin is concentrated in the basal layer of sebocytes and associates with FN fibers

(A) Cryosection of adult SG stained with antibodies to EMB (gray) and a basement membrane marker laminin (LN, yellow) with DAPI nuclear counterstain (blue).

(B) Quantification of EMB expression in the different parts of tail sebaceous glands. Box plots show area covered by EMB staining in basal, lower, and upper SG. n = 15 SGs from 5 adult mice.

(C) Schematic of SG locations studied by immunogold EM.

(D–F) TEM electron micrographs of mouse tail SG with EMB, immunogold labeling showing EMB in suprabasal cell-cell contacts (D), cell-basement membrane contacts (E), and membrane protrusions (F). Gold particles in the cell-cell contact (D) or cell-basement membrane contact (E) are marked with white arrowheads. Dotted line indicates the cell border in (F).

(G) Cryosections of mouse back skin collected at P0, P2, P5, and P10 and labeled with antibodies against fibronectin (gray) and EMB (red).

(H) Cryosections of adult mouse tail skin stained with antibodies against fibronectin (gray) and counterstained with DAPI (blue).

(I) Quantification of proximal fibronectin in peripheral sebaceous glands (WT, n = 25; Emb^−/−, n = 23) (Figure S4B). Sebaceous glands were pooled from 5 WT and 4 Emb^−/− mice.

(J) AFM stiffness measurements of regions in proximity to the basal SG layer. Individual measurements (WT, n = 1,050; Emb^−/−, n = 1,080) were pooled from 4 WT and 4 Emb^−/− mice.

Two-tailed t test for independent means was used to determine the statistical significance. ∗∗∗∗p < 0.00005, ∗p < 0.05. Scale bars: 50 μm (A, G, and H) or 1 μm (D–F) in electron micrographs.