dsRNA Viruses Flashcards
Which family was studied in the dsRNA virions?
Reoviridae
Give a very brief description of reoviridae tissue tropism and transmission.
Broad host range and transmission via food, water, and arthropod vectors.
What does the REO in Reoviridae stand for?
Respiratory Enteric Orphan Virus
What kind of serotypes does Reovirus have?
T1L, T2J, and T3D
Where does Reovirus replicate in host cells?
Inclusion bodies / Viral factories
What BSL level do Reoviruses belong in? Why?
BSL1. They don’t cause diseases in humans
What are the clinical trials of reovirus attempting to do?
Be used as an anti cancer agent because they seem to lyse cancer cells.
How does reovirus help decrease cancer in a host?
It causes immunogenic cell death by killing cells directly and indirectly by lysis and by increasing activating cytokines respectively.
Describe rotavirus
Rotavirus is a dsRNA virus which is the most common cause of severe diarrhea in infants and young children. Clinical presentation has changed from GI infection to plasma viremia
How is rotavirus transmitted?
Via fecal-oral route.
What is the primary infection of the rotavirus?
It infects the small intestine causing gastroenteritis and destroys gut cells causing malabsorption. Now it is also available systemically causing plasma viremia.
Describe the physical structure of rotavirus
Has a triple capsid structure in 3 forms: virion, ISVP, and the core
Describe the breakdown of the physical structure of rotavirus in the host
Virion undergoes proteolytic cleavage in GI tract or within endocytic vesicle
Infections subvirion particle
Delivery of transcriptionally active core to the plasma
Describe rotavirus genome
11 segments of dsRNA of various lengths. 5’ polyphosphate cap on each strand to enhance viral RNA stability.
Explain how the rotavirus genome could play a part in antigenic shift.
Rotavirus genome is segmented and therefore it could incorporate new/double/less in the developing capsids which could drastically change the function of the genome due to reassortment and lead to antigenic shift.
How does rotavirus replicate?
Attachment via VP4 prot and clathrin mediated endocytosis
Loses outermost layer (VP4-7) in endosome
Early transcription in double layered particles
dsRNA never exposed to cytoplasm
Replication in viral factories
Late transcription in progeny cores
Double layered particles are coated with VP6 which bud across membrane through ER
Mature virions released during cell death
What is copy choice recombination?
RdRp or RT switches from one RNA template to another during synthesis while still bound to the NA chain so there could be mixed ancestry.
What kind of genomes favour template switching?
Intergenic and interprotein domains are usually immune because they have a secondary RNA structure that makes it more likely that template switching will be non-disruptive.
