NS5A GENE PRODUCT & MECHANISM OF HEPATITIS C VIRUS INTERFERON RESISTANCE

感染者对干扰素的反应 HCV是可变的。最近的研究表明， HCV NS 5A基因中的IFN敏感性决定区（ISDR）， 与干扰素耐药性相关的基因NS 5A还 被证明是一种磷蛋白， 在病毒复制和病毒-宿主相互作用中起重要作用。 由于NS 5A的功能重要性，我们的实验室 进行实验以表征其功能并识别 作为HCV基因功能靶点的细胞因子 产品利用酵母双杂交系统， 与NS 5A特异性相互作用。许多 这些克隆编码具有SH 3和/或SH 3结合结构域的蛋白质 其中一些是已知的基因， 转导功能。这些克隆与NS 5A的相互作用 GST融合体外结合试验也证实了这一点。是 有趣的是，注意到几个富含脯氨酸的序列（类似于 SH 3结合结构域）存在并位于ISDR区域的侧翼， NS5A。实验正在进行中，以解决功能性 这些互动的意义。还正在努力 评估NS 5A序列变异的临床意义。 这种病毒-细胞相互作用的详细表征， 与临床疾病的相关性可能有助于我们理解 HCV复制和肝细胞损伤的机制。

Response to interferon of patients infected with HCV has been variable. Recent studies suggested a region, termed IFN sensitivity determining region (ISDR) in the HCV NS5A gene, that are associated with resistance to interferon. The NS5A has also been shown to be a phosphoprotein and probably plays an important role in viral replication and viral-host interaction. Because of the functional importance of NS5A, our laboratory is conducting experiments to characterize its functions and identify cellular factors that are the functional targets of this HCV gene product. Using the yeast two hybrid system, 13 independent clones that interact specifically with NS5A have been identified. Many of these clones encode proteins with SH3 and/or SH3 binding domains and some of them are known genes with putative signal transduction functions. Interactions of these clones with NS5A were also confirmed in the GST-fusion in vitro binding assay. It is interesting to note that several proline-rich sequences (similar to SH3 binding domain) are present and flank the ISDR region in NS5A. Experiments are under way to address the functional significance of these interactions. Effort is also being initiated to evaluate the clinical significance of sequence variations in NS5A. Detailed characterization of this virus-cell interaction and correlation to clinical disease may contribute to our understanding of HCV replication and mechanisms of hepatocellular injury.