Dermoskeleton morphogenesis in zebrafish fins

Abstract

Zebrafish fins have a proximal skeleton of endochondral bones and a distal skeleton of dermal bones. Recent experimental and genetic studies are discovering mechanisms to control fin skeleton morphogenesis. Whereas the endochondral skeleton has been extensively studied, the formation of the dermal skeleton requires further revision. The shape of the dermal skeleton of the fin is generated in its distal growing margin and along a proximal growing domain. In these positions, dermoskeletal fin morphogenesis can be explained by intertissue interactions and the function of several genetic pathways. These pathways regulate patterning, size, and cell differentiation along three axes. Finally, a common genetic control of late development, regeneration, and tissue homeostasis of the fin dermoskeleton is currently being analyzed. These pathways may be responsible for the similar shape obtained after each morphogenetic process. This provides an interesting conceptual framework for future studies on this topic. Developmental Dynamics 239:2779–2794, 2010. © 2010 Wiley-Liss, Inc.

Limited dedifferentiation provides replacement tissue during zebrafish fin regeneration

“…One substantial difference between Class 2 and Class 3 mosaics was that the latter had a more punctate pattern of mCherry + cells that were concentrated at lepidotrichia joints. Since intra-ray fibroblasts and osteoblasts reside within and adjacent to lepidotrichia, respectively (Akimenko et al, 2003; Poss et al, 2003; Mari-Beffa and Murciano, 2010), we sectioned the same fins photographed in Figure 1G–H* and stained them with antibodies against osteoblast specific proteins. We observed that the Class 3 cells shown in Figure 1H and H* were positive for the osteoblast marker zns-5 (Johnson and Weston, 1995; Wills et al, 2008 and Fig.…”

“…The caudal fin is a favored model of regeneration since it is easy to amputate, is not required for viability, regenerates all parts of its anatomy, and completely regenerates in a short time frame (2 weeks). The zebrafish caudal fin is composed of bony ray segments, known as lepidotrichia that are joined together by ligaments (Mari-Beffa et al, 2007; Mari-Beffa and Murciano, 2010). These rays form by direct mineralization coordinated by osteoblasts, specialized cells that deposit bone matrix (Karsenty et al, 2009).…”

Metamorphosis in Teleosts

“…Numerous pathways regulate positioning and outgrowth of these rays and the joints within the rays (Marí-Beffa & Murciano, 2010; Sims, Eble, & Iovine, 2009). Early proximo-distal patterning in the fin bud, largely controlled by Fgf signaling, is thought to establish a “prepattern” for ray positioning.…”

Segmentation pattern of zebrafish caudal fin is affected by developmental temperature and defined by multiple fusions between segments

“…In future studies, it should be interesting to examine whether the observed thermally induced plasticity of the caudal fin is mediated by alterations of the expression of genes like fgfs, shh, bmp2b , and cx43 , which are involved in the growth and differentiation of the caudal‐fin rays (Govindan & Iovine, ; Lee, Grill, Sanchez, Murphy‐Ryan, & Poss, ; Quint et al, ; Sims, Eble, & Iovine, ; Wills, Kidd, Lepilina, & Poss, ). Such alterations might occur at the level of individual genes, or be part of a thermally induced modification of the “positional identity” gradient, a prespecification gradient that controls the position‐dependent growth and differentiation of fin rays (Mari‐Beffa & Murciano, ; Rabinowitz et al, ).…”