In vivo imaging of bone collagen dynamics in zebrafish

Type I collagen plays a pivotal role in shaping bone morphology and determining its physical properties by serving as a template for ossification. Nevertheless, the mechanisms underlying bone collagen formation, particularly the principles governing its orientation, remain unknown owing to the lack of a method that enables continuous in vivo observations. To address this challenge, we constructed a method to visualize bone collagen by tagging with green fluorescent protein (GFP) in zebrafish and observed the interactions between osteoblasts and collagen fibers during bone formation in vivo. When collagen type I alpha 2 chain (Col1a2)-GFP was expressed under the control of the osteoblast-specific promoters