The efficacy of a single treatment 1 hpi points to this mechanism, as transcription would be the dominant viral intracellular process occurring at this time
The efficacy of a single treatment 1 hpi points to this mechanism, as transcription would be the dominant viral intracellular process occurring at this time. each ebolavirus, resulting in differences in genome transcription efficiency. Most pronounced was the effect of the nucleoprotein and the 3-untranslated region. These data suggest that there are intrinsic specificities in the polymerase complex and untranslated signaling regions that could offer insight regarding observed pathogenic differences. Further adding to the differences in the polymerase complexes, posttransfection/contamination treatment with the compound remdesivir (GS-5734) showed a greater inhibitory effect against BDBV than EBOV. The delayed growth kinetics of BDBV and the greater susceptibility to polymerase inhibitors indicate that disruption of the polymerase complex is a viable target for therapeutics. IMPORTANCE Ebolavirus disease is usually a viral contamination and is fatal in 25 to 90% of cases, depending on the viral species and the amount of supportive care available. Two species have caused Fosbretabulin disodium (CA4P) outbreaks Fosbretabulin disodium (CA4P) in the Democratic Republic of the Congo, (EBOV) and (BDBV). Pathogenesis and clinical outcome differ between these two species, but there is still limited information regarding the viral mechanism for these differences. Previous studies suggested that BDBV replicates slower than Rabbit polyclonal to Transmembrane protein 57 EBOV, but it is usually unknown if this is due to differences in the polymerase complex and its role in transcription and replication. This study details the construction of a minigenome replication system that can be used in a biosafety level 2 laboratory. This system will be important for studying the polymerase complex of BDBV and comparing it with other filoviruses Fosbretabulin disodium (CA4P) and can be used as a tool for screening inhibitors Fosbretabulin disodium (CA4P) of viral growth. consists of the genera (1). There are six different species of ebolaviruses: (EBOV), (SUDV), (BDBV), (TAFV), (RESTV), and the newly discovered (BOMV) (2). With the exception of RESTV and BOMV, ebolaviruses are known to cause severe disease in humans, and EBOV, SUDV, and BDBV all have caused outbreaks of hemorrhagic fever across Africa. The largest ebolavirus outbreak recorded, caused by EBOV, occurred in West Africa from 2013 to 2016 and resulted in over 28,000 cases and a case fatality rate (CFR) of 63% for confirmed cases (3). BDBV, the most recently emerged ebolavirus, is responsible for two outbreaks, one in Bundibugyo, Uganda, in 2007 and one in the DRC in 2012. The BDBV outbreaks had an average CFR of 37% compared to 55% for SUDV and 76% for EBOV outbreaks in central Africa (4,5). Importantly, EBOV, SUDV, and BDBV are all endemic to this region at the border of the DRC and Uganda, indicating a need to fully understand the virology and pathology of these three species in order to gain insight for the development of effective medical countermeasures. Filoviruses are nonsegmented, negative-stranded RNA viruses that replicate using a combination of packaged viral proteins and host cell proteins. The genome of BDBV, as with the other ebolaviruses, contains seven structural proteins, four of which make up the polymerase complex. These proteins are the nucleoprotein (NP), viral protein 35 (VP35), viral protein 30 (VP30), and the catalytic subunit of the polymerase complex encoded by the large gene (L). NP encapsidates the viral RNA, VP35 acts as a polymerase cofactor and a bridge between NP and L, and VP30 is usually a transcriptional coactivator (reviewed in references 6 and 7). Interactions between these proteins, specifically between NP and VP35 (8, 9) and between VP35 and L (10), are vital to the proper function of the polymerase. VP30 is only necessary for transcription and is not required for genomic replication (11, 12). The efficiency of the polymerase complex is an important component to determining viral replication rates as transcription and genome replication creates not only new virion components but also proteins involved in evading the immune response. The genomic untranslated regions (UTR), the 3-leader and 5-trailer, are also implicated in the regulation of transcription and replication. There is evidence suggesting that this terminal nucleotides in the 3-UTR are specific to the genera for initiation of transcription, as the EBOV and Lloviu virus (LLOV) polymerase complexes cannot transcribe chimeric minigenomes with the terminal nucleotides from Marburg virus (MARV) (13, 14). In addition, EBOV cannot transcribe minigenomes made up of the 3-UTR from MARV, although MARV can transcribe in the presence of the EBOV 3-UTR (12). The ability of the polymerase complex and host proteins to interact with the 5-UTR is necessary for antigenome to genome replication (7, 15, 16). and data examining BDBV contamination indicates that this viral kinetics.