Wang Jian, Karabinos Anton, Zimek Alexander, Meyer Michael, Riemer Dieter, Hudson Clare, Lemaire Patrick, Weber Klaus
Department of Biochemistry, Max Planck Institute for Biophysical Chemistry, Goettingen, Germany.
Eur J Cell Biol. 2002 May;81(5):302-11. doi: 10.1078/0171-9335-00246.
The urochordate Ciona intestinalis is a well established system for embryological studies, and large scale EST sequences begin to emerge. We cloned five cytoplasmic intennediate filament (IF) cDNAs and made specific antibodies to the recombinant proteins. Self-assembly studies and immunofluorescence microscopy were used to study these proteins and their distribution. Confirming and extending previous studies in Styela, we found that Ciona protein IF-A is expressed in muscle and forms homopolymeric filaments while proteins IF-C and IF-D, which form only obligatory heteropolymeric filaments, resemble a keratin pair exclusively found in the entire epidermis. Protein IF-B and the new protein IF-F potentially reflect tunicate-specific IF proteins. They are found in the entire internal epithelia including the neural gland. We also extended the analysis to earlier developmental stages of Ciona. Protein IF-A is expressed in muscle from larval stages, whereas proteins IF-C and IF-D are found only in the tail epidermis. Protein IF-F is detected abundantly in the test cells of eggs, embryos and premetamorphic larvae. Our studies show that IF proteins could prove very useful markers in the study of cell fate determination in Ciona. They also support previous findings on the evolutionary relationships of different IF proteins. Non-vertebrate chordates have IF proteins which represent orthologs of vertebrate type I to III proteins, but also IF proteins that do not seem to fit into these classes. However, the intron positions of all tunicate IF genes are conserved with vertebrate type I to III genes, pointing to a common evolutionary origin.
尾索动物海鞘是胚胎学研究中一个成熟的系统，大规模的EST序列也开始出现。我们克隆了五个细胞质中间丝（IF）cDNA，并制备了针对重组蛋白的特异性抗体。利用自组装研究和免疫荧光显微镜来研究这些蛋白质及其分布。在证实并扩展了先前对柄海鞘的研究后，我们发现海鞘蛋白IF-A在肌肉中表达并形成同聚丝，而仅形成 obligatory 异聚丝的蛋白IF-C和IF-D类似于仅在整个表皮中发现的一对角蛋白。蛋白IF-B和新蛋白IF-F可能反映了被囊动物特有的IF蛋白。它们存在于包括神经腺在内的整个内部上皮中。我们还将分析扩展到海鞘的早期发育阶段。蛋白IF-A从幼虫阶段就在肌肉中表达，而蛋白IF-C和IF-D仅在尾部表皮中发现。蛋白IF-F在卵母细胞、胚胎和变态前幼虫的测试细胞中大量检测到。我们的研究表明，IF蛋白可能是研究海鞘细胞命运决定的非常有用的标记。它们也支持了先前关于不同IF蛋白进化关系的发现。非脊椎动物脊索动物具有代表脊椎动物I型至III型蛋白直系同源物的IF蛋白，但也有似乎不属于这些类别的IF蛋白。然而，所有被囊动物IF基因的内含子位置与脊椎动物I型至III型基因是保守的，这表明它们有共同的进化起源。
