Okamoto Eri, Moriyama Yuuta, Kuraku Shigehiro, Kai Kei-Ichi, Tanaka Mikiko
School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.
Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Hyogo, Japan.
Dev Growth Differ. 2019 Jan;61(1):97-103. doi: 10.1111/dgd.12591.
In amniotes, limb muscle precursors de-epithelialize from the ventral dermomyotome and individually migrate into limb buds. In catsharks, Scyliorhinus, fin muscle precursors are also derived from the ventral dermomyotome, but shortly after de-epithelialization, they reaggregate within the pectoral fin bud and differentiate into fin muscles. Delamination of muscle precursors has been suggested to be controlled by hepatocyte growth factor (HGF) and its tyrosine kinase receptor (MET) in amniotes. Here, we explore the possibility that HGF/MET signaling regulates the delamination of appendicular muscle precursors in embryos of the catshark Scyliorhinus canicula. Our analysis reveals that Hgf is expressed in pectoral fin buds, whereas c-Met expression in fin muscle precursors is rapidly downregulated. We propose that alteration of the duration of c-Met expression in appendicular muscle precursors might underlie the evolution of individually migrating muscle precursors, which leads to the emergence of complex appendicular muscular systems in amniotes.
在羊膜动物中，肢体肌肉前体细胞从腹侧生皮节脱离上皮状态，并单独迁移到肢体芽中。在猫鲨（Scyliorhinus）中，鳍肌肉前体细胞也源自腹侧生皮节，但在脱离上皮状态后不久，它们在胸鳍芽内重新聚集并分化为鳍肌肉。在羊膜动物中，有人提出肌肉前体细胞的分层受肝细胞生长因子（HGF）及其酪氨酸激酶受体（MET）控制。在这里，我们探讨了HGF/MET信号通路调节猫鲨（Scyliorhinus canicula）胚胎中附肢肌肉前体细胞分层的可能性。我们的分析表明，Hgf在胸鳍芽中表达，而鳍肌肉前体细胞中的c-Met表达迅速下调。我们提出，附肢肌肉前体细胞中c-Met表达持续时间的改变可能是单个迁移肌肉前体细胞进化的基础，这导致了羊膜动物中复杂附肢肌肉系统的出现。
