First Set of VIR Cards Flashcards
Picornavirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
(+)ssRNA
naked nucleocapsid (therefore icosohedral)
REPLICATION:
- Enters cell; rep occurs in cytosol
- Its +sense ssRNA genome serves as mRNA—> expressed as one big polypeptide
- cleaved forming viral prots + RNA-dep RNA pol
- RNA pol forms -sense RNA template which is then used to make more viral genomes
- assemble and make crystals in the cytosol
EXAMPLES: polio, coxsackie, ECHO, rhion, HAV
Reovirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = 11 dsRNA segments
Virion = naked icosohedral
REPLICATION:
- attaches to ß-adrenergic recept.
- in cytosol, RNA-dep RNA pol synths mRNA from 11 segs
- these are then translated in the nucleus, including another RNA pol which…
- synths (-)sense RNA
- released by lysis
EXAMPLES:
rotaviruses
Orthomyxoviruses
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = multiple (-)ssRNAs (each in their own helical nucleocapsid)
virion = enveloped helical
REPLICATION:
1) Virion dsorbs to cell via H->sialic acid interaction
2) virion contains RNA-dep RNA pol b/c genome is (-)ssRNA, but unique to RNA virus, it replicates its genome in the NUCLEUS
3) Translation and assembly in the cytosol
4) Bud out
EXAMPLES: influenza
Paramyxoviruses
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single (-)ssRNA
Virion = helical enveloped
REPLICAITON:
1) also uses hemagglutinin to adsorb to cell
2) have only one RNA segment (therefore no antigenic shift) and replicates genome in cytosol, but otherwise similar to influenza/orthomyxoviridae: Virion contains RNA-dependent RNA pol, budding, etc.
EXAMPLES: parainfluenza (Croup), RSV, Measles, mumps
Rhabdovirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single (-)ssRNA
virion = helical enveloped
REPLICAITON:
EXAMPLES: rabies
coronavirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single (+)ssRNA
virion = helical enveloped
REPLICATION:
1) adsorbs via its HA
2) (+) genome is translated in cytosol into two large polypeps which are “self-cleaved by the virus-encoded protease”
3) envelope from ER (unique)
EXAMPLES: common cold (2nd most important cause après rhinos); SARS-assoc’d coronavirus
togavirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single (+)ssRNA
virion = icosahedral enveloped
REPLICATION:
1) uncoats in cytosol, 2) (+)ssRNA genome is translated into several structural and non-structural proteins (i.e. not just one large polypeptide like poliovirus), 3) makes RDRP to make (-)ssRNA template of its genome, 4) buds out through plasmalemma
EXAMPLES: rubella, arboviral encephalitises (WNV, EEE, WEE, etc.)
Retroviruses
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = two identical (+) ssRNA
virion = nous ne savons pas…
REPLICATION:
EXAMPLES: HIV-1, tumor dzs
parvovirus
Nucleic acid set-up?
Virion structure?
Replicaiton ?
Examples?
NA = single, linear ssDNA
virion = smallest human virus; icosahedral naked
Replication: adsorption—>moves to nuc for replication—>ssDNA has “hairpin loops” that ~=dsDNA where cell’s DNA pol’s synth progeny genomes—>mRNA from dsDNA intermediate by cell’s RNA pols—>assembled in nucleus
EXAMPLES: B-19 (slapped cheeks)
papovirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single, circular, dsDNA
vir = icosahedral naked
REPLICATION:
EXAMPLES: HPV
adenovirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single, linear dsDNA
vir = naked icosahedral
REPLICATION:
Use unique fiber protruding from each of its twelve vertices to attach—>penetrates/uncoats—>viral DNA to nucleus where host DNA-dep RNA pol transcribe early genes—>splicing enzymes remove introns (introns were discovered in adenoviruses!)—>early mRNAs translated in cytosol into nonstructural prots—>viral DNA replicated—> late mRNAs for structural prots then translated—>assembly in nucleus—>released by lysis [i.e. not budding]
EXAMPLES: colds, conjunctivitis, etc.
Herpesvirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single, linear dsDNA
vir = icosahedral enveloped
REPLICATION
- fusion
- DNA—>nucleus
- mRNA goes out to cytosol, is translated and then those early prots go BACK to the nuc to act as transcription factors
- enveloped temporarily from nucleus
- get permanent envelope from the Golgi
- delivered as vesicle to cell surface
EXAMPLES
HSV, varicela-zoster, CMV, EBV
Poxvirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single, linear dsDNA
virion = enveloped w/o symmetry
REPLICATION:
EXAMPLES: Smallpox, Molluscum contageosum
Hepadnavirus
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
NA = single, circular dsDNA (for most of its length; bizzare)
virion = icosahedral enveloped PLUS spherical and filamentous antigenic/sub-viral particles (also bizzare!)
REPLICATION:
1) in nucleus, virion’s DNA pol synths rest of DNA making circular viral genome
2) template for mRNA synth w/ host RNA pol
3) full-length (-)RNA made from this which will be converted into new DNA genome w/ reverse transcriptase encoded for by virion’s genome
EXAMPLES: HBV
Calciviruses
Nucleic acid set-up?
Virion structure?
How does it multiply?
Examples?
(+)ssDNA
Virion = small, non-eveloped
Rep = poorly understood
Examples: Norwalk virus (norovirus)
differ from picornaviruses in that they have: larger genome and distinctive spikes on their surface
