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Figure 3. Comparison of the Col1a1, Col1a2, and Col2a1 expression patterns during Xenopus tropicalis hindlimb development. Stage NF54 (top panel) or NF60 (bottom panel) hindlimbs were examined by whole mount Alizarin red staining (insets), sectioned along the proximo-distal axis and stained with HES, (A–C, M–O) or processed by in situ hybridization for the Xt-Col1a1, Xt-Col1a2, and Xt-Col2a1 probes, (D–L, P–X). Results are shown for the whole skeletal element (left column, scale bar: 500 μm) and higher magnifications of the diaphysis (middle column, scale bar: 50 μm) and epiphysis (right column, scale bar: 50 μm). Arrows and arrowheads show osteoblasts and osteocytes, respectively. In situ hybridization signal is light to dark blue, and brown endogenous X.t. pigment cells are visible on most sections. Legend: Bo, bone; Ch, chondrocytes; Me, medulla; Pe, perichondrium; Sm, striated muscles. |
