Functional RNA Structures in the 3'UTR of Tick-Borne, Insect-Specific and No-Known-Vector Flaviviruses.

Roman Ochsenreiter,Michael Wolfinger,Ivo Hofacker

doi:10.3390/v11030298

Abstract

Untranslated regions (UTRs) of flaviviruses contain a large number of RNA structural elements involved in mediating the viral life cycle, including cyclisation, replication, and encapsidation. Here we report on a comparative genomics approach to characterize evolutionarily conserved RNAs in the 3UTR of tick-borne, insect-specific and no-known-vector flaviviruses in silico. Our data support the wide distribution of previously experimentally characterized exoribonuclease resistant RNAs (xrRNAs) within tick-borne and no-known-vector flaviviruses and provide evidence for the existence of a cascade of duplicated RNA structures within insect-specific flaviviruses. On a broader scale, our findings indicate that viral 3UTRs represent a flexible scaffold for evolution to come up with novel xrRNAs.

Highlights

Flaviviruses are small, single-stranded positive-sense RNA viruses that are typically transmitted between arthropod vectors and vertebrate hosts
The genus Flavivirus within the Flaviviridae family comprises more than 70 species, which are organized into four groups, each with a specific host association: Mosquito-borne flaviviruses (MBFVs) and tick-borne flaviviruses (TBFVs) spread between vertebrate and invertebrate hosts, whereas insect-specific flaviviruses (ISFVs) replicate in mosquitoes and no-known-vector flaviviruses (NKVs) have only been found in rodents and bats, respectively
Emerging and re-emerging MBFVs such as Dengue virus (DENV), Japanese encephalitis virus (JEV), West Nile virus (WNV), Yellow fever virus (YFV) or Zika virus (ZIKV) are the causative agents of large-scale outbreaks that result in millions of human and veterinary infections every year [4]

Summary

Introduction

Flaviviruses are small, single-stranded positive-sense RNA viruses that are typically transmitted between arthropod vectors and vertebrate hosts They are endemic in tropic and sub-tropic regions and represent a global health threat, humans are considered dead end hosts in many cases. The genus Flavivirus within the Flaviviridae family comprises more than 70 species, which are organized into four groups, each with a specific host association: Mosquito-borne flaviviruses (MBFVs) and tick-borne flaviviruses (TBFVs) spread between vertebrate (mammals and birds) and invertebrate (mosquitoes and ticks) hosts, whereas insect-specific flaviviruses (ISFVs) replicate in mosquitoes and no-known-vector flaviviruses (NKVs) have only been found in rodents and bats, respectively. Emerging and re-emerging MBFVs such as Dengue virus (DENV), Japanese encephalitis virus (JEV), West Nile virus (WNV), Yellow fever virus (YFV) or Zika virus (ZIKV) are the causative agents of large-scale outbreaks that result in millions of human and veterinary infections every year [4]

Methods

Results

Conclusion