Figure 1. Bglap as a tendon sheath specific marker.

(A) Fluorescent immunohistochemistry of mouse sheath tissues of the adult Tibialis anterior tendon at 2 months old (n = 5 mice per group). Scale bar, 40 μm. (B) QRT-PCR analysis of sheath-specific markers using adult mouse sheath and tendon tissues as shown. Relative expression levels were normalized to β-tubulin and the sheath tissues. Data are means ± s.e.m and were analyzed using Student’s t-tests. *p≤0.013; **p≤0.0014. n = 3 mice per group. (C) Images of peroneus longus and brevis tendon (upper panel) and Tibialis anterior tendon (lower panel) of the BGLAP-Cre;Rosa26^mT/mG mice at 2 months old. Dotted lines depict the boundaries of the tendon fibers. GFP signals are observed in the tendon sheath tissues (n = 5 mice per group). Scale bar, 250 μm. (D) Cross-sections of fluorescent microscopic analysis of the extensor tendons and flexor tendons of Rosa26^mT/mG and BGLAP-Cre;Rosa26^mT/mG mice. Scale bar, 50 μm (n = 5). (E) QRT-PCR analysis of sheath-specific markers using sheath and tendon cells isolated from the BGLAP-Cre;Rosa26^mT/mG mice after cell-sorting for green fluorescence (GFP). Relative expression levels were normalized to Gapdh and the sheath cells. Data are means ± s.e.m and were analyzed using a Student’s t-tests. **p≤0.0062. n = 3 biological replicates per group. Additional data for this figure are provided in Figure 1—figure supplement 1.

Figure 1—figure supplement 1. Fluorescence-assisted cell-sorting (FACS) analysis of sheath-derived cells.

(A) Cells dissociated from the Tibialis anterior sheath tissues of the BGLAP-Cre;Rosa26^mT/mG mice after cell-sorting for GFP and tdTomato signals. (B) The number of colonies was counted in a colony-formation assay using sheath-derived cells (GFP⁺) isolated from the BGLAP-Cre;Rosa26^mT/mG mice with two different initial cell-seeding densities of 1000 or 2000 cells. (C) Cell morphology of sorted cells in vitro. Scale bar, 20 μm.