replication of ds RNA virus Flashcards
what does the genome structure look like of dsRNA virus?
genome is segmented (but more types of protein than mRNA can be produced)
what does the virion structure of dsRNA look like?
complex, 3-layered protein shell
insensitive to detergents (non-enveloped) but glycoproteins
3 layers: virion
2 layers: subviral particle
1 layer: core
explain the replication cycle of reoviridae
1.receptor binding via hemagluttin and endocytosis
2.acid induced proteolysis within the endosome: conversion of the virion into infectious subviral particle –> this can also already happen in intestine
3.penetration through endosomal membrane into cytoplasm
4.cytoplasm: conversion from ISVP to core particle
5.synthesis of capped viral mRNA takes place into core particle
6.association of mRNAs with newly translated proteins to RNase sensitive subviral particles SVP
7.transcription of mRNA into - strand and formation of RNA resistant SVP with 10 dsRNA segments
8.formation of virions by assembly of preformed outer capsid proteins
how does the structural organisation of the RNA in the rotavirus core particle look like?
25 % of dsRNA in ordered structure
Is naked RNA infectious? Is dsRNA ever naked?
naked RNA not infectious –> dsRNA is never naked –> always together with viral proteins
where does the RNA transcription of rotaviruses take place?
in double layered core particle
mRNA leaves core particles via channels
each channel has polymerase and capping enzyme
–> dsRNA formation in virion –> dsRNA is never exposed to cytoplasm
where do reoviral subviral particles mature? How do they receive the outer capsid proteins?
mature at the viroplasm and bud into the ER and receive the outer capsid proteins (glycoproteins)
how can reoviruses and retroviruses enter the cytoplasm?
use of hydrophobic parts to cross the membrane
reovirus; cathepsin B/L cleaves molecules off which locally dissolve membrane
rotavirus: Trypsin cleaves to expose hydrophobic parts
what are the characteristics of blue tongue disease? (animals, transmission, variability, virus family, diagnosis)
animals: sheep, cattle, goat
transmission: gnats
variability: high –> 24 serotypes
virus family: reoviridae
diagnosis: Pathogen detection via RT-PCR or Ab detection via ELISA
why can real time RT-PCR only be used at the very beginning of infection? What can be detected in later stages and how?
viral RNA eventually eradicated by immune system –> no detection
later: serology test for antibodies –> detect antibodies via ELISA, NT
how was blue tongue disease countered and controlled?
duty of disclosure
prohibition of transfer
zones
export szop
monitoring
quarantine
immunisation