Browsing by Author "Rutmane, Anna"

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A Comparative Study of Mayaro Virus TRVL and BeAr Strains
(Tartu Ülikool, 2025) Rutmane, Anna; Varjak, Margus, juhendaja; Merits, Andres, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Tehnoloogiainstituut
Mayaro virus (MAYV) is an arthritogenic alphavirus and the causative agent of Mayaro fever, which is characterized by myalgia, arthralgia, high fever, and maculopapular rash. Currently, the distribution of MAYV is limited to Central and South America, where it causes sporadic outbreaks. However, in recent years, there have been concerns about its potential emergence into urban transmission cycles. Phylogenetically, MAYV is divided into three distinct genotypes: D, L, and N. In this study, we investigate two MAYV strains: TRVL (genotype D) and BeAr (genotype L). To compare the replication and transcription efficiencies between the two strains, we implement a trans-replication system, in which the expression of alphavirus replicase and RNA replication are uncoupled. Our study indicates that the replicase of the TRVL strain is more active in human cells, whereas the replicase of the BeAr strain is more active in mosquito cells. The differences in replicase activity between the strains are driven by determinants located both within the replicase itself and within conserved sequence elements. Lastly, our experiments demonstrate that TRVL and BeAr strains are capable of co-infection.
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Induction of type I IFN response by alphavirus replicases in the absence of viral RNA templates
(Tartu Ülikool, 2023) Rutmane, Anna; Omler, Ailar, juhendaja
Alphaviruses are arthropod transmitted viruses with global distribution and wide host range. Upon infection, some alphaviruses may cause acute muscle pain, arthritis, rash, and encephalitis. In the past decades alphavirus-caused epidemics are not uncommon, but despite that there are currently no licensed vaccines or antiviral drugs for any of the alphavirus species. During viral replication and transcription, alphavirus replicase generates 5’-triphosphate RNA and double-stranded RNA (dsRNA), which trigger type I interferon production. Remarkably, it has been shown that SFV and SINV replicases induce IFN- response in absence of viral RNA templates by generating 5’-ppp dsRNA from host cell RNA. In the current work we investigated whether some other alphavirus replicases possess such property and how it differs in human and insect cells. We observed that other alphavirus replicases can generate IFN-inducing RNA without presence of viral RNA templates. We also concluded that correlation between replicase’s ability to transcribe and replicate viral RNA template and its ability to synthesize IFN-inducing RNA from host’s cellular RNA is not universal attribute of all alphaviruses.