Animal Replication Flashcards
tropism
specificity of a virus to a particular tissue/cell type
Animal Virus Entry
fusion
some enveloped viruses leave their envelopes at the host cell membrane during entry or at the endosome following receptor mediated endocytosis
Animal Virus Entry
receptor mediated endocytosis
membrane invagination pulls the virus into the cell in an endosome
Animal Virus Entry
uncoating
process of removing the nucleocapsid can occur due to enzymes/pH changes in the endosome or following the escape from the endosome
Animal Virus Release: Budding and lysis
host cell lysis
viral proteins puncture the host plasma membrane
Animal Virus Release: Budding and lysis
budding
often occurs at the same time as envelope formation
Double-Stranded (ds) DNA virus synthesis
tegument
layer of proteins between nucleocapsid and envelope
Double-Stranded (ds) DNA virus synthesis
productive infection
lyse cell releasing 50,000 - 200,000 virions
Double-Stranded (ds) DNA virus synthesis
latent infection
- virions are undetected can be reactivated after months/years
- different than a chronic infection
Double-Stranded (ds) DNA virus synthesis
chronic infection
a slow increase in viral load
Understanding RNA Viruses
Sense (+) RNA strands
can be used as mRNA
Understanding RNA Viruses
Anti-Sense (-) RNA strands
must be transcribed into sense (+) RNA prior to translation, serve as the template for sense (+) synthesis
Understanding RNA Viruses
RNA-dependent RNA polymerase
almost all RNA viruses (except retroviruses) require a virally encoded enzyme to transcribe and replicate RNA
Understanding RNA Viruses
replicase
RdRp that replicates a viral RNA genome (more error prone than DdDp)
Understanding RNA Viruses
transcriptase
an RdRp that synthesizes mRNA
Sense (+) RNA Virus Synthesis
nonstructural proteins (NSP)
include enzymes for viral processes
Sense (+) RNA Virus Synthesis
structural proteins (SP)
include spike proteins
Sense (+) RNA Virus Synthesis
accessory proteins (AP)
involved in interfering with cellular processes and the innate immune response
Sense (+) RNA Virus Synthesis
spike glycoprotein
associates with the ACE2 receptor and is cleaved to induce fusion
Antisense (-) RNA Virus Synthesis
hemagluttinin spikes (HA)
attaches to sialic acid moieties linked to glycoproteins and glycolipids on cells in teh respiratory epithelium
Antisense (-) RNA Virus Synthesis
neuraminidase spike (NA)
facilitates induction of receptor mediated endocytoosis and separation of the virus from the host cell during budding
Retrosviruses
reversetranscriptase (RT)
- converts ssRNA into dsDNA
- functions as RpDp, DdDp, and a ribonuclease
Retroviruses
integrase
inserts viral dsDNA into the host chromosome
dsDNA Virus
Location of Nucleic Acid Synthesis.
nucleus
dsDNA Virus
Steps of viral nucleic acid synthesis.
dsDNA –> dsDNA