IMAGE

Fig. 4

ID
ZDB-IMAGE-120427-9
Source
Figures for Singh et al., 2012
Image
Figure Caption

Fig. 4

New Osteoblasts Arise in the Regenerates of Osteoblast-Depleted Fins through De Novo Differentiation (A) Cartoon depicting strategy that combines inducible lineage tracing and cell ablation in the osx:CreER; β-act2:RSG; osx:NTR background. 4-HT treatment imparts a β-actin2-driven EGFP label in osteoblasts. (B and C) 4-HT labels osteoblasts of uninjured fins with EGFP fluorescence (B). This label was undetectable after Mtz treatment (C), indicating efficient osteoblast ablation. (D) After amputation of fins of 4-HT-labeled and Mtz-treated animals, EGFP label was not detectable in 4 dpa regenerates or portions of the fins proximal to the injury site. Because the label was driven by the β-actin2 promoter, this result indicates that EGFP loss in (C) was due to cell ablation and not downregulation of an osteoblast marker. (E–G) A second 4-HT treatment at 2 dpa generated EGFP+ cells in 3, 4, and 7 dpa regenerates, but not in portions of the fins proximal to the injury site. This result indicates that, although β-actin2 expressing osteoblasts are not contributed by uninjured fin regions, the regenerated osteoblasts can still be labeled by EGFP via their expression of osx:CreER and β-act2:RSG after amputation. (H) Longitudinal section of uninjured fin corresponding to (C), indicating lack of EGFP fluorescence after 4-HT labeling and subsequent Mtz treatment. (I) Longitudinal section of 3 dpa regenerate corresponding to (E), indicating that EGFP fluorescence induced by a postamputation 4-HT label is present in the osteoblast compartment of the regenerated portion only. Scale bar = 100 μm. See Figure S4.

Acknowledgments
This image is the copyrighted work of the attributed author or publisher, and ZFIN has permission only to display this image to its users. Additional permissions should be obtained from the applicable author or publisher of the image.

Reprinted from Developmental Cell, 22(4), Singh, S.P., Holdway, J.E., and Poss, K.D., Regeneration of amputated zebrafish fin rays from de novo osteoblasts, 879-886, Copyright (2012) with permission from Elsevier. Full text @ Dev. Cell