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Functional analysis of the chemokine and chemokine receptors encoded by human herpesvirus 6.

人疱疹病毒6编码的趋化因子和趋化因子受体的功能分析。

基本信息

批准号：
11670295
负责人：
ISEGAWA Yuji
金额：
$ 2.5万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Human henpesvirus 6(HHV-6), which belongs to the betaherpesvirus subfamily and infects mainly T cells and mononuclear cells in vitro, causes acute and latent infections. Two variants of HHV-6 have been distinguished on the basis of differences in several properties. We have determined the complete DNA sequence of HHV-6 variant B(HHV-6B)strain HST, the causative agent of exanthem subitum, and compared the sequence with that of variant A strain U1102. A total of 115 potential open reading frames(ORFs)were identified within the 161,573-bp contiguous sequence of the entire HHV-6 genome, including some genes with remarkable differences in amino acid identity. U83 of strain HST encodes a chemokine, which functions as a chemoattractant for monocytes. Similarly, U83 of strain U1102 encodes a chemokine homolog, but it does not contain a signal peptide sequence. Thus, U83 of strain U1102 may not be secreted and thus cnnot exert its chemotactic activity. If U83 functions as a chemoattractant in v … More ivo, it is possible that HHV-6 can easily spread through cell-to-cell infection, even in the presence of neutral antibodies. U12 of strain Z29 is truncated and dose not encode a calcium-mobilizing receptor for CC-chemokines which is encoded by that of strain HST.Nobody know the pathogenesis of strain Z29. These findigns suggested that the product of U12 may play an important role in the pathogenesis of HHV-6 through transmembrane signaling by binding with CC-chemokines.We have cloned the U83 gene and analyzed the biological function of this gene. The U83 gene contained an ORF encoding a 113-amino-acid peptide, starting at the first methionine and containing a possible signal peptide and the typical cysteine residues chanacteristic of the chemokines. Reverse transcription-PCR analysis of mRNA and immunofluorescent-antibody testing of infected cells both indicated that the encoded protein was a late protein. The ORF U83 gene fused to the FC gene was expressed as a fusion protcin in COS-7 cells by tnansfection, and the fusion protein was purified from the supernatant of transfected cells to test its biological function. The purified protein was capable of inducing transient calcium mobilization in THP-1 cells and of chemotactically activating THP-1 cells. These findings suggested that the U83 protein might play an important role in HHV-6 propagation in vivo by activating and trafficking mononuclear cells to sites of vira replication, thus aiding the development of superbly efficient virus production mechanisms. Less

人疱疹病毒6（HHV-6）属于乙型疱疹病毒亚家族，体外主要感染T细胞和单核细胞，可引起急性和潜伏性感染。HHV-6的两种变体已经根据几种特性的差异进行了区分。我们测定了引起麻疹的HHV-6变异B（HHV-6B）株HST的完整DNA序列，并与变异A株U1102进行了比较。在整个HHV-6基因组161573 bp的连续序列中，共鉴定出115个潜在的开放阅读框（orf），其中包括一些氨基酸同源性差异显著的基因。菌株HST的U83编码一种趋化因子，对单核细胞起趋化作用。同样，菌株U1102的U83编码一个趋化因子同源物，但不包含信号肽序列。因此，菌株U1102的U83可能不会分泌，从而不能发挥其趋化活性。如果U83在病毒体内起化学引诱剂的作用，那么HHV-6很可能通过细胞间感染传播，即使存在中性抗体。菌株Z29的U12被截断，不编码由菌株HST编码的cc趋化因子钙动员受体。没有人知道菌株Z29的发病机制。这些发现提示U12的产物可能通过与cc趋化因子结合的跨膜信号通路在HHV-6的发病过程中发挥重要作用。我们克隆了U83基因，并分析了该基因的生物学功能。U83基因包含一个编码113个氨基酸的肽的ORF，从第一个蛋氨酸开始，包含一个可能的信号肽和趋化因子特有的典型半胱氨酸残基。mRNA逆转录- pcr分析和感染细胞免疫荧光抗体检测均表明编码蛋白为晚期蛋白。将与FC基因融合的ORF U83基因以融合蛋白的形式在COS-7细胞中转染表达，并从转染细胞的上清液中纯化融合蛋白，检测其生物学功能。纯化后的蛋白能够在THP-1细胞中诱导瞬时钙动员，并对THP-1细胞进行化学活化。这些发现表明，U83蛋白可能在HHV-6的体内繁殖中发挥重要作用，通过激活和运输单个核细胞到病毒复制位点，从而促进了高效病毒生产机制的发展。少