Establishment of a Bone-Specific col10a1:GFP Transgenic Zebrafish

Abstract

During skeletal development, both osteogenic and chondrogenic programs are initiated from multipotent mesenchymal cells, requiring a number of signaling molecules, transcription factors, and downstream effectors to orchestrate the sophisticated process. Col10a1, an important downstream effector gene, has been identified as a marker for maturing chondrocytes in higher vertebrates, such as mammals and birds. In zebrafish, this gene has been shown to be expressed in both osteoblasts and chondrocytes, but no study has reported its role in osteoblast development. To initially delineate the osteogenic program from chondrogenic lineage development, we used the zebrafish col10a1 promoter to establish a transgenic zebrafish expressing a GFP reporter specifically in osteoblast-specific bone structures that do not involve cartilaginous programs. A construct harboring a ~2.2-kb promoter region was found to be sufficient to drive the reporter gene in osteoblast-specific bone structures within the endogenous col10a1 expression domain, confirming that separable cis-acting elements exist for distinct cell type-specific expression of col10a1 during zebrafish skeletal development. The ~2.2-kb col10a1:GFP transgenic zebrafish marking only bone structures derived from osteoblasts will undoubtedly be an invaluable tool for identifying and characterizing molecular events driving osteoblast development in zebrafish, which may further provide a differential mechanism where col10a1 is involved in the development of chondrocytes undergoing maturation in other vertebrate systems.

Complexity in the Wiring and Regulation of Plant Circadian Networks

“…Subsequently, LHY was likely added during green plant evolution as complications from multi-cellularity arose. Indeed insights into early and diverse plant circadian systems already suggests wide conservation and evidence for expansion of clock gene families resulting from genome duplication events throughout evolution [30][31][32][33][34]. Therefore contributions from comprehensive lineage specific circadian systems will be valuable to understanding how the clock model has evolved into a complex network in plants.…”

Zinc finger transcription factor Sp7/Osterix acts on bone formation and regulates col10a1a expression in zebrafish

“…Mouse Col10a1 encodes the alpha chain of type X collagen that belongs to a short chain collagen, and functions only in hypertrophic chondrocytes during endochondral ossification [51]. col10a1a was shown to be expressed in both chondrocytes and osteoblasts in zebrafish and other fish such as medaka [26,52]. In this study, we provided evidence that Sp7 is able to bind to the Sp1 sites of the zebrafish col10a1a promoter to activate col10a1a expression in a way similar to how Sp7 to regulate col1a1 and col1a2 [17,53].…”

“…S3). Runx2 as a transcription factor also can bind to RBS (Runx2-binding site) to regulate expression of col1a1, col1a2 and col10a1, and be a critical transcription factor for early chondrogenesis and osteoblast differentiation [52,[54][55][56][57][58]. Because of no altered expression of runx2a and runx2b in the sp7À/À (Fig.…”

“…In contrast, the expression level of Col10a1 is normal in Sp7 null mutant mouse, suggesting that Sp7 has no effects on Col10a1 in mice [5]. Zebrafish col10a1a is expressed in osteoblasts and chondrocytes [52], but the role and underlying mechanism of col10a1a in osteoblast development are not yet clear. We conducted in situ hybridization.…”

Pannexin 3 is required for normal progression of skeletal development in vertebrates

“…In zebrafish, panx3 expression was first detected in the cl, which is formed via intramembranous ossification at 48 hpf and maintained until 72 hpf, but this expression disappeared when the cl was mineralized, as assessed via alizarin red staining at 96 hpf (Fig. 2) (33). Similarly, panx3 expression in the intramembranous op was shown to be restricted to the nonmineralized region (Fig.…”