THE ROLE OF THE NUCLEAR ENVELOPE IN INTRACELLULAR PROTEIN SORTING

穿过核孔复合体的运输是一个重要的过程， 调节细胞生长和正常发育。 的结构 核孔及其在核运输中的作用正在研究中， 分子水平。 此前，该实验室已经证明， 孔复合物由糖蛋白家族组成， 连接的O-连接的N-乙酰葡糖胺。 主要核的糖基化 孔糖蛋白p62已被详细检查。 大鼠cDNA和基因 已经分离出编码大鼠p62的基因。 一级序列检查 揭示了一系列14个重复的五肽基序， 序列GFSFG。 针对该五肽序列产生的兔抗血清 不仅与p62反应，还与核孔的其他成员反应 糖蛋白家族 这些抗血清已被用于分离cDNA 编码其他核孔糖蛋白。 此外，退化 对应于五肽重复序列的寡核苷酸已经被用作 使用聚合酶链分离额外cDNA种类的引物 反应技术 检查核孔的功能 核转运中的糖蛋白，体外核组装， 运输系统已经使用。 当DNA被加入到 非洲爪蟾核改革与完整的核包膜和核 毛孔 这些提取物可耗竭内源性核孔 组分和重组或生化改变的孔 proteins. 用这种方法显示了核孔的组装和运输 需要核孔糖蛋白; O-连接的N-乙酰葡糖胺 部分可以被修饰而不改变转运。 能够产生 其他核孔糖蛋白的重组形式应该允许 进一步解剖这些核孔的功能作用， 件.

Transport across the nuclear pore complex is an essential process for regulating cell growth and normal development. The structure of the nuclear pore and its involvement in nuclear transport are being studied at a molecular level. Previously the laboratory has shown that the nuclear pore complex is made up of a family of glycoproteins having covalently attached O-linked N-acetylglucosamine. Glycosylation of the major nuclear pore glycoprotein p62 has been examined in detail. The rat cDNA and gene encoding rat p62 have been isolated. Examination of the primary sequence of p62 revealed a series of 14 repeating pentapeptide motifs having the sequence GFSFG. Rabbit antisera raised against this pentapeptide sequence react not only with p62 but also with the other members of the nuclear pore glycoprotein family. These antisera have been used to isolate the cDNAs encoding other nuclear pore glycoproteins. In addition, degenerate oligonucleotides corresponding to the pentapeptide repeat have been used as primers for isolating additional cDNA species using the polymerase chain reaction technique. To examine the function of the nuclear pore glycoproteins in nuclear transport, an in vitro nuclear assembly and transport system has been employed. When DNA is added to extracts of Xenopus laevis nuclei reform with intact nuclei envelopes and nuclear pores. These extracts can be depleted of endogenous nuclear pore components and reconstituted with recombinant or biochemically altered pore proteins. Using this assay nuclear pore assembly and transport were shown to require nuclear pore glycoproteins; the O-linked N-acetylglucosamine moiety can be modified without altering transport. The ability to generate recombinant forms of other nuclear pore glycoproteins should allow a further dissection of the functional roles of these nuclear pore components.