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Figure 5.
C-dots deposit at sites of active bone mineralization. (A–C) Regenerated caudal fin of uninjected fish (A), injected with C-dots at 7 dpa (B), or injected at 4 dpa (C). All fish were stained with Alizarin Complexone (ALC) at 8 dpa and imaged. Composite images were generated by superimposing photographs obtained using transmitted light, a 488/525 nm filter set to capture C-dots’ fluorescence (pseudo colored green), and a 596/615 nm filter set to capture C-dots/ALC’s fluorescence (pseudo colored magenta). ALC-positive areas (indicative of ossification) that lack C-dots appear magenta, and areas of ossification with C-dot deposition appear white. Posterior end of fin toward top of images. Site of amputation is indicated with arrowheads and the plane of sections (D)–(L) are indicated with dotted lines. (D–L) Transverse sections of fins, imaged and pseudo colored as in (A)–(C). (D’–L’) Magnified bone regions from D–E (white squares). Areas of C-dot deposition are indicated with white arrows. Ossified regions devoid of C-dots are indicated with black arrows. Asterisks indicate the bone matrix. Double asterisk in K’ indicates areas of matrix buildup at the site of amputation. Scale bars are 500 µm for (A)–(C), 50 µm for (D)–(L) and 5 µm for (D’)–(L’).