Candiani S, Pestarino M
Istituto di Anatomia Comparata, Università di Genova, Italy.
J Comp Neurol. 1998 Mar 16;392(3):343-51.
Lancelets, known also as amphioxus, are protochordates that share common archetypal features with vertebrates. Recently, several developmental and molecular biology studies have pointed out homologies between anatomical structures of lancelets and vertebrates. We have studied the head region of the lancelet, Branchiostoma lanceolatum, by means of scanning electron microscopy, immunocytochemistry, and Western blotting techniques, to localize the pituitary-specific transcription factor, Pit-1. Immunoreactive Pit-1 protein has been found in cells of two typical structures of the lancelets, the Kölliker's and Hatschek's pits. Moreover, the frontal eye complex, neurons, and the rostral nerves show Pit-1 immunoreactivity. A band of 33 kilodaltons has been resolved in lancelet extracts by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and after Western blotting, the bands have been probed by a monoclonal antibody to rat Pit-1. Our results demonstrate that Pit-1 is expressed in both neurones and receptosecretory epithelial cells of adult lancelets, and that the cells lining the two pits display ultrastructural and immunocytochemical features typical of chemoreceptosecretory/olfactory- and adenohypophyseal-like structures.
文昌鱼，也被称为蛞蝓鱼，是原索动物，与脊椎动物具有共同的原型特征。最近，一些发育生物学和分子生物学研究指出了文昌鱼和脊椎动物解剖结构之间的同源性。我们通过扫描电子显微镜、免疫细胞化学和蛋白质免疫印迹技术研究了文昌鱼（Branchiostoma lanceolatum）的头部区域，以定位垂体特异性转录因子Pit-1。在文昌鱼两个典型结构——科利克氏窝和哈氏窝的细胞中发现了免疫反应性Pit-1蛋白。此外，额眼复合体、神经元和吻神经也显示出Pit-1免疫反应性。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳在文昌鱼提取物中分离出一条33千道尔顿的条带，蛋白质免疫印迹后，用抗大鼠Pit-1单克隆抗体对这些条带进行检测。我们的结果表明，Pit-1在成年文昌鱼的神经元和感受分泌上皮细胞中均有表达，并且两个窝内衬的细胞表现出化学感受分泌/嗅觉样和腺垂体样结构的典型超微结构和免疫细胞化学特征。
