Weber P, Montag D, Schachner M, Bernhardt R R
Department of Neurobiology, Swiss Federal Institute of Technology, Hönggerberg, HPM, Zürich.
J Neurobiol. 1998 Apr;35(1):1-16.
A cDNA clone encoding tenascin-W, a novel member of the tenascin family, was isolated from a 20- to 28-h postfertilization (hpf) zebrafish cDNA library on the basis of the conserved epidermal growth factor-like domains represented in all tenascin molecules. An open reading frame of 2796 base pairs encodes a mature protein consisting of heptad repeats, a cysteine-rich amino terminal region, 3.5 epidermal growth factor-like repeats, five fibronectin type III homologous repeats, and a domain homologous to fibrinogen. These domains are the typical modular elements of molecules of the tenascin family. Sequence comparison demonstrated that TN-W shares homologies with the members of the tenascin family but is not a species homolog of any identified tenascin. The expression pattern of tn-w was analyzed by in situ hybridization in 1-day-old embryos, in 3-day-old larvae, and in juvenile zebrafish. At 24-25 hpf, tn-w mRNA was expressed in the lateral plate mesoderm, most conspicuously in the presumptive sclerotome. Migrating cells of sclerotomal and neural crest origins also showed high levels of expression. At 3 days, expression by sclerotomal and neural crest cells continued to be observed while expression in the somitic mesoderm was decreased. In juvenile fish, tn-w was expressed weakly by cells in the myosepta and, more strongly, by presumably nonneuronal cells in the dorsal root ganglia. In these tissues and at the same developmental stages, the expression of tn-w partially overlapped with the distribution of tn-c mRNA. In addition, tn-c was expressed in the central nervous system (CNS) and in the axial mesoderm, neither of which expressed tn-w at any of the age stages examined. The expression pattern of tn-w suggests an involvement in neural crest and sclerotome cell migration and in the formation of the skeleton. Similar and possibly overlapping functions could also be performed by tn-c, which appears to have additional functions during the development of the CNS.
基于所有腱生蛋白分子中保守的表皮生长因子样结构域，从受精后20至28小时（hpf）的斑马鱼cDNA文库中分离出一个编码腱生蛋白-W（腱生蛋白家族的一个新成员）的cDNA克隆。一个2796个碱基对的开放阅读框编码一种成熟蛋白，该蛋白由七肽重复序列、富含半胱氨酸的氨基末端区域、3.5个表皮生长因子样重复序列、五个纤连蛋白III型同源重复序列以及一个与纤维蛋白原同源的结构域组成。这些结构域是腱生蛋白家族分子的典型模块化元件。序列比较表明，TN-W与腱生蛋白家族成员具有同源性，但不是任何已鉴定腱生蛋白的物种同源物。通过原位杂交分析了tn-w在1日龄胚胎、3日龄幼虫和幼年斑马鱼中的表达模式。在24至25 hpf时，tn-w mRNA在侧板中胚层表达，最明显的是在推定的生骨节中。生骨节和神经嵴来源的迁移细胞也显示出高水平的表达。在3天时，继续观察到生骨节和神经嵴细胞的表达，而体节中胚层的表达则下降。在幼年鱼中，tn-w在肌隔细胞中表达较弱，而在背根神经节中可能的非神经元细胞中表达较强。在这些组织以及相同的发育阶段，tn-w的表达与tn-c mRNA的分布部分重叠。此外，tn-c在中枢神经系统（CNS）和轴向中胚层中表达，在所检查的任何年龄阶段，这两个部位均不表达tn-w。tn-w的表达模式表明其参与神经嵴和生骨节细胞迁移以及骨骼形成。tn-c可能也具有类似且可能重叠的功能，并且在CNS发育过程中似乎具有额外的功能。
