Developmental mechanisms of migratory muscle precursors in medaka pectoral fin formation
Developmental mechanisms of migratory muscle precursors in medaka pectoral fin formation
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DOI：
10.1007/s00427-018-0616-9
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发表时间：
2018-07
影响因子：
2.4
通讯作者：
Saori Tani-Matsuhana;R. Kusakabe;Kunio Inoue
中科院分区：
文献类型：
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作者：
Saori Tani-Matsuhana;R. Kusakabe;Kunio Inoue
肢肌由迁移性肌肉前体细胞（MMPs）形成，其从皮肌节的腹侧区域分层并迁移到肢芽中。MMP在迁移过程中保持未分化，在到达肢体后开始分化为骨骼肌。然而，目前还不清楚MMPs的发育机制是否在硬骨鱼类中是保守的。本文研究了硬骨鱼类青鳉胸鳍肌肉的发育。MMP markerlbx1的表达首先观察到在几个体节之前的鳍芽的外观。lbx1阳性细胞随后向前移动，并定位在未来的鳍芽区域分化成骨骼肌细胞。为了解决鳍肌形成的发育机制，我们敲除了tbx5，这是鳍芽形成所需的基因。tbx 5变体显示鳍芽的丧失，而lbx 1的表达在前体节中正常起始。与正常胚胎不同，flbx 1的表达在迁移的鳍MMPs或鳍芽中没有维持。我们认为，鳍MMPs似乎经历了两个阶段，在他们的发展，与初始规格的MMPs发生独立的鳍芽和第二鳍芽依赖的MMP迁移和增殖的阶段。我们的研究结果表明，青鳉鳍肌是由基质金属蛋白酶。这表明，鳍肌形成的发育机制在包括青鳉在内的硬骨鱼类中是保守的。通过这项研究，我们也提出了新的见解，在鳍芽形成的MMPs的发育机制。
Limb muscles are formed from migratory muscle precursor cells (MMPs) that delaminate from the ventral region of dermomyotomes and migrate into the limb bud. MMPs remain undifferentiated during migration, commencing differentiation into skeletal muscle after arrival in the limb. However, it is still unclear whether the developmental mechanisms of MMPs are conserved in teleost fishes. Here, we investigate the development of pectoral fin muscles in the teleost medakaOryzias latipes. Expression of the MMP markerlbx1is first observed in several somites prior to the appearance of fin buds.lbx1-positive cells subsequently move anteriorly and localize in the prospective fin bud region to differentiate into skeletal muscle cells. To address the developmental mechanisms underlying fin muscle formation, we knocked down tbx5, a gene that is required for fin bud formation. tbx5 morphants showed loss of fin buds, whereaslbx1expression initiated normally in anterior somites. Unlike in normal embryos, expression oflbx1was not maintained in migrating fin MMPs or within the fin buds. We suggest that fin MMPs appear to undergo two phases in their development, with an initial specification of MMPs occurring independent of fin buds and a second fin bud-dependent phase of MMP migration and proliferation. Our results showed that medaka fin muscle is composed of MMPs. It is suggested that the developmental mechanism of fin muscle formation is conserved in teleost fishes including medaka. Through this study, we also propose new insights into the developmental mechanisms of MMPs in fin bud formation.