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Structure, Function and Role of Vertebrate -Galactoside-binding Lectin

脊椎动物半乳糖苷结合凝集素的结构、功能和作用

基本信息

批准号：
62580133
负责人：
KASAI Ken-ichi
金额：
$ 1.02万
依托单位：
Teikyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62580133/
关键词：
Lectin -Galactoside Chick Embryo Human Placenta Amino Acid Sequence cDNA Morphogenesis ガン化 βーガラクトシド

项目摘要

Since -galactoside-binding lectin is found in most vertebrates and seen to be expressed in embryonic as well as tumor tissues remarkably, it is thought to participate in fundamental biological control mechanisms not elucidated so far. We have studied it from various points of view to clarify its physiological function as well as to open the way to apply it to medical use. Firstly, we completely determined the amino acid sequence of human placenta lectin using a protein sequencer. We also succeeded in the isolation of a cDNA clone for it and determined its nucleotide sequence. A cDNA for chick 16K lectin was also cloned and most of the protein-coding region was sequenced. The primary structures including that of chick 14K type determined before were compared and shown to be highly homologous one ANO ther (e.g. human placente/chick 14K, 50% identical), and thus it is obvious that they were originated from a common ancestor protein.The property that they do not contain any cleavable signal sequence at their N-terminus in spite of their extracellular localization is also common among them. The above human lectin cDNA was inserted into an expression vector to obtain E. coli cells that produce human lectin. They are expected to supply large amount of lectin enough to study the medical application of it. Histochemical observation using electron microscopy and anti-chick 14K lectin antibody has shown that it is distributed in and around the desmosome of epidermal cells suggesting its participation to the cell-to-cell interaction. Furthermore, studies on tumor tissues have shown that this kind of lectin also exists as a free molecule, which quite differs from that in normal tissue where most of it binds to other molecules. It is very interesting since it is suggested that the state of the lectin changes in accordance with transformation.

由于β-半乳糖苷结合凝集素在大多数脊椎动物中发现，并被认为是在胚胎以及肿瘤组织中显着表达，它被认为是参与基本的生物控制机制尚未阐明至今。我们从不同的角度对其进行了研究，以阐明其生理功能，并开辟其在医学上应用的途径。首先，我们利用蛋白质测序仪测定了人胎盘凝集素的氨基酸序列。我们还成功地分离了它的cDNA克隆，并确定了它的核苷酸序列。还克隆了鸡16 K凝集素的cDNA，并对大部分蛋白编码区进行了测序。将包括鸡14 K型在内的一级结构进行比较，结果表明，它们之间具有高度同源性（如人胎盘/鸡14 K，50%相同），因此，它们显然起源于一个共同的祖先蛋白，尽管它们位于细胞外，但它们的N-末端不含任何可裂解的信号序列的性质也是它们之间的共同点。将上述人凝集素cDNA插入表达载体中，获得E.产生人类凝集素的大肠杆菌细胞。电镜和抗鸡14 K凝集素抗体的组织化学观察表明，它分布在表皮细胞的桥粒内及其周围，提示它参与了细胞与细胞的相互作用。此外，对肿瘤组织的研究表明，这种凝集素也以游离分子形式存在，这与正常组织中的凝集素大部分与其他分子结合有很大不同。这是非常有趣的，因为有人建议，凝集素的状态变化，根据转换。