Li Xin-Yi, Lin Yu-Shuang, Zhang Hong-Wei
Shaanxi Normal University, Xi'an, China.
Dongwuxue Yanjiu. 2012 Aug;33(4):389-94. doi: 10.3724/SP.J.1141.2012.04389.
In amphioxus, we found a mesoderm related gene, tropomyosin, which encodes a protein comprising 284 amino acid residues, sharing high identities with other known Tropomyosin proteins both in vertebrates and invertebrates. Phylogenetically, amphioxus Tropomyosin fell outside the invertebrate clade and was at the base of the vertebrate protein family clade, indicating that it may represent an independent branch. From the early neurula to the larva stage, whole-mount in situ hybridization and histological sections found transcripts of amphioxus tropomyosin gene. Weak tropomyosin expression was first detected in the wall of the archenteron at about 10 hours-post-fertilization neurula stage, while intense expression was revealed in the differentiating presumptive notochord and the muscle. Transcripts of tropomyosin were then expressed in the formed notochord and somites. Gene expression seemed to continue in these developing organs throughout the neurular stages and remained till 72-hours, during the early larval stages. In situ study still showed tropomyosin was also expressed in the neural tube, hepatic diverticulum, notochord and the spaces between myotomes in adult amphioxus. Our results indicated that tropomyosin may play an important role in both embryonic development and adult life.
在文昌鱼中，我们发现了一个与中胚层相关的基因——原肌球蛋白，它编码一种由284个氨基酸残基组成的蛋白质，与脊椎动物和无脊椎动物中其他已知的原肌球蛋白蛋白具有高度同源性。在系统发育上，文昌鱼原肌球蛋白不属于无脊椎动物分支，而是位于脊椎动物蛋白家族分支的基部，这表明它可能代表一个独立的分支。从早期神经胚到幼虫阶段，通过整体原位杂交和组织切片发现了文昌鱼原肌球蛋白基因的转录本。在受精后约10小时的神经胚阶段，首先在原肠壁中检测到微弱的原肌球蛋白表达，而在分化中的假定脊索和肌肉中则显示出强烈的表达。然后原肌球蛋白的转录本在形成的脊索和体节中表达。在整个神经胚阶段，基因表达似乎在这些发育中的器官中持续存在，并在幼虫早期阶段一直持续到72小时。原位研究还表明，在成年文昌鱼中，原肌球蛋白也在神经管、肝憩室、脊索和肌节之间的间隙中表达。我们的结果表明，原肌球蛋白可能在胚胎发育和成年生活中都发挥着重要作用。
