Impacts of HIV-1 resistance mutations associated with nucleoside reverse transcriptase inhibitors on viral fitness / 病毒学报

Nucleoside reverse transcriptase inhibitors which act as a major component of highly active antiretroviral therapy regimens are widely used in treatment of Acquired Immune Deficiency Syndrome. However, the emergence of drug-resistant variants of HIV-1 severely limits the effectiveness of these drugs. Many drug resistance mutations confer a fitness cost, which can be partially overcome by compensatory mutations or other molecular mechanisms. This review focuses on the impacts of resistance mutations emerging during treatment with nucleoside reverse transcriptase inhibitors on viral fitness, and inter actions between these mutations.

Effect of Hepatitis C Virus Core Protein on Interferon-Induced Antiviral Genes Expression and Its Mechanisms / 中国病毒学

Emerging data indicated that HCV subverts the antiviral activity of interferon (IF); however,whether HCV core protein contributes to the process remains controversial. In the present study, we examined the effect of HCV core protein on interferon-induced antiviral gene expression and whether the effect is involved in the activation and negative regulation of the Jak/STAT signaling pathway. Our results showed that, following treatment with IFN-α, the transcription of PKR, MxA and 2'-5'OAS were down-regulated in HepG2 cells expressing the core protein. In the presence of HCV core protein,ISRE-dependent luciferase activity also decreased. Further study indicated that the core protein could inhibit the tyrosine phosphorylation of STAT1, whereas the level of STAT1 expression was unchanged.Accordingly, SOCS3, the negative regulator of the Jak/STAT pathway, was induced by HCV core protein. These results suggests that HCV core protein may interfere with the expression of some interferon-induced antiviral genes by inhibiting STAT1 phosphorylation and induction of SOCS3.