Mechanical role of actinotrichia in shaping the caudal fin of zebrafish
Mechanical role of actinotrichia in shaping the caudal fin of zebrafish
复制标题
放线菌在斑马鱼尾鳍塑造中的机械作用
DOI：
10.1016/j.ydbio.2021.09.003
复制
发表时间：
2021
影响因子：
2.7
通讯作者：
Toshihiro Aramaki and Shigeru Kondo
中科院分区：
文献类型：
--
作者：
Hibiki Nakagawa;Junpei Kuroda;Toshihiro Aramaki and Shigeru Kondo
鱼叉状胶原复合物，被称为放线菌，位于硬骨鱼鳍尖的表皮细胞层之下，已知有助于鳍的形成；然而，它们的具体作用在很大程度上仍不清楚。在这项研究中，我们通过产生col9a1c （col9a1c）敲除斑马鱼来研究放线菌在尾鳍形成中的作用。虽然在基因敲除的鱼中，放线菌最初是正常产生的，排列正确，但随着鱼的生长，放线菌的数量减少，排列混乱。同时，鳍尖在背腹方向逐渐缩短，整个鳍呈椭圆形，鳍射线很少分叉，而是融合，表明放线菌是鳍在背腹方向展开的必要条件。此外，通常在正常鱼类中薄分布的上皮细胞在基因敲除的鱼类中变成球形，减少了每个细胞覆盖的面积，从而减少了鳍尖的面积。总之，这些发现表明放线菌的紧密排列在背腹方向上提供了物理支持，使尾鳍呈三角形扩张。
Spear-like collagen complexes, known as actinotrichia, underlie the epidermal cell layer in the tip of teleost fins and are known to contribute toward fin formation; however, their specific role remains largely unclear. In this study, we investigated of actinotrichia in the role of caudal fin formation by generatingcollagen9a1c(col9a1c)-knockout zebrafish. Although actinotrichia were initially produced normally and aligned correctly in the knockout fish, the number of actinotrichia decreased as the fish grew and their alignment became disordered. Simultaneously, the fin tip gradually shortened in the dorsal-ventral direction and the entire fin became oval-shaped, while the fin-rays rarely bifurcated and instead underwent fusion, suggesting that actinotrichia are essential for spreading fins dorsoventrally. Furthermore, the epithelial cells that are usually thinly spread in normal fish became spherical in the knockout fish, reducing the area covered by each cell and thus the area of the fin tip. Together, these findings suggest that the tight alignment of actinotrichia provides physical support in the dorsal-ventral direction that allows caudal fins to expand in a triangular-shape.