A cDNA library of short random fragments derived from four of the five genes of the rabies virus genome has been used to isolate genetic suppressor elements (GSEs) expressed intracellularly that inhibit rabies virus replication. Two nucleotide fragments, one from the rabies virus nucleocapsid protein (N) gene and the other from the phosphoprotein (P) gene, have been identified as inhibitors of rabies virus replication in cell culture. The N cDNA fragment is expressed in sense-orientation and could produce a dominant negative protein affecting virus replication. The P cDNA fragment is expressed in the inhibitory antisense direction. Inhibition of rabies virus replication was detected in cell culture using an ELISA for detection of rabies virus glycoprotein expression on the cell surface and immunofluorescence for detection of intracellular rabies virus N expression. Both the sense and antisense GSEs, because of their targeted inhibition of rabies virus replication, have possible uses in rational design of antiviral compounds for treatment of rabies. This approach could be applied to any virus, particularly to those that lyse their target host cell.
"Especially in the field of HIV mutants of gag, env or rev were generated that have DN effects with the intend to produce HIV resistant T cells [103,104]. The targeted virus needs not to be a retrovirus, since a truncated N gene of rabies virus for example could inhibit viral replication in cell culture . "
[Show abstract][Hide abstract] ABSTRACT: Investigating and assigning gene functions of herpesviruses is a process, which profits from consistent technical innovation. Cloning of bacterial artificial chromosomes encoding herpesvirus genomes permits nearly unlimited possibilities in the construction of genetically modified viruses. Targeted or randomized screening approaches allow rapid identification of essential viral proteins. Nevertheless, mapping of essential genes reveals only limited insight into function. The usage of dominant-negative (DN) proteins has been the tool of choice to dissect functions of proteins during the viral life cycle. DN proteins also facilitate the analysis of host-virus interactions. Finally, DNs serve as starting-point for design of new antiviral strategies.
[Show abstract][Hide abstract] ABSTRACT: The RNA interference (RNAi) technology has been recognized as a promising antiviral therapy for a few years. One of the potential limitations for applying this technology against wild type rabies virus is its high rate of genetic variation. Recently, an RNAi vector system that incorporated modified dsRNA within microRNA structure [or artificial miRNAs(amiRNAs)] has been described. This allowed expression of multiple amiRNAs of single or multiple targets from a single construct. In this study, we evaluated a benefit of using amiRNA vector against different rabies strains. We found that applying single targeting amiRNA against challenged rabies virus standard (CVS) rabies nucleocapsid (N) mRNA resulted in more than 90% reduction of viral genome in Neuro2A cells up to 72 h after infection. Multiple amiRNAs aiming at single or multiple NmRNA target(s) yielded comparable inhibitory results as with a single amiRNA against perfectly matched target. Although the level of each mature miRNA generated from multiple amiRNA construct was slightly reduced as assessed by stem-loop RT and real-time PCR techniques, its effectiveness remained unchanged even when an ineffective or scrambled amiRNA was also included in the transcript. Against highly pathogenic wild type virus, single amiRNA construct activity was reduced when mismatching with target sequence occurred at critical site whereas multiple targeting amiRNA construct remained highly effective. Our results suggest the benefit of using multiple targeting amiRNAs when confronting with wild type rabies virus, the sequence of which is not completely known.
Antiviral research 08/2009; 84(1):76-83. DOI:10.1016/j.antiviral.2009.07.012 · 3.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In recent years, no major paradigm shifts have occurred in the utilization of new products for the prevention and control of rabies. Development of new cost-effective rabies biologics and antiviral drugs is critical in continuing to prevent and reduce disease. Current rabies vaccines are highly effective but have developed largely based on technical improvements in the vaccine industry. In the future, alternative approaches for improved vaccines, including novel avirulent rabies virus (RABV) vectors, should be pursued. Any rabies vaccine that is effective without the need for rabies immune globulin (RIG) will contribute fundamentally to disease prevention by reducing the cost and complexity of postexposure prophylaxis (PEP). The lack of high quality, affordable RIG is a continuing problem. Virus-specific monoclonal antibodies (mAbs) will soon fulfill the PEP requirement for passive immunity, currently met with RIG. Several relevant strategies for mAb production, including use of transgenic mice, humanization of mouse mAbs, and generation of human immune libraries, are underway. As a result of successful PEP and pre-exposure prophylaxis in developed countries, until recently, no significant focused efforts have been devoted to RABV-specific antiviral agents. To date, combination therapy including broad spectrum antiviral agents has been successful in only one case, and reports of antiviral activity are often conflicting. Current antiviral strategies target either the nucleoprotein or phosphoprotein, but drugs targeting the viral polymerase should be considered. Considering the lag from creation of new concepts to experimental development and clinical trials, many years will likely elapse between today's ideas and tomorrow's practices.
Advances in Virus Research 01/2011; 79:345-63. DOI:10.1016/B978-0-12-387040-7.00016-0 · 4.57 Impact Factor
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