Lecture 4 part 1 Flashcards
(45 cards)
state the envelope, capsid, and genome of paramyxoviruses
envelope – pleomorphic with specific viral attachment proteins (VAPs)
nucleocapsid – helical
genome – large, ssRNA(-) viruses; LINEAR genome
the 3 genera of paramyxoviruses are distinguished by what?
the VAPs (viral attachment proteins)
paramyxoviruses cause major diseases including……
measles
mumps
RSV
paramyxoviruses invade cells via ____ and are released by _____
invade cells via membrane fusion and released by budding
what is the name of the viral attachment protein on paramyxoviruses for MUMPS?
HN (hemagglutinin-neuraminidase)
what is the name of the viral attachment protein on paramyxoviruses for MEASLES
H (hemagglutinin)
true or false
the mumps and measles viruses have a single serotype
true
what is the name for the measles virus
morbillivirus
paramyxovirus is:
the mumps virus AND parainfluenza virus 1-4
what is the name of the RSV virus
pneumovirus
RSV AND metapneumovirus
explain the replication scheme of paramyxoviruses
genome is ssRNA(-)
to make protein:
ssRNA(-) is converted to ssRNA(+) via viral RNA dependent RNA polymerase. ssRNA(+) is like mRNA. translated into viral proteins
to make genome:
ssRNA(-) is converted to ssRNA(+) by RNA dependent RNA polymerase to serve as a template for generating more copies.
RNA dependent RNA polymerase then converts this ssRNA(+) back into ssRNA(-) to package into newly made virus
what are the 3 classes of proteins associated with paramyxoviruses
nucleocapsid associated proteins
VAP’s (produced in host cell)
matrix protein
name the nucleo-capsid associated proteins in paramyxoviruses and state their function
NP (nucleoprotein) – bind and protect viral RNA
P – polymerase phosphoprotein – facilitates viral RNA replication
L (RNA polymerase)
name the VAPS made by paramyxoviruses and state where they are made
made IN THE HOST CELL
F protein – membrane protein that promotes fusion and viral entry
HN (MUMPS VAP)
H (MEASLES VAP)
m protein – matrix protein – associated with the assembly of virions
state the envelope, capsid, and genome of togaviruses
envelope – has envelope. 2 GLYCOPROTEIN SPIKES
capsid – icosahedral
genome – ssRNA(+) viruses
where do togaviruses replicate?
in the cytoplasm
where does the togavirus infect and does it spread?
togavirus infects the upper respiratory tract.
spreads via viremia (blood) to lymphoid tissue, skin, and other organs
the togavirus causes what disease?
what is another name for this disease?
rubella – german measles
explain the replication scheme of the togavirus
genome of togavirus = ssRNA(+)
to make protein:
ssRNA(+) directly binds to the host ribosome and makes protein
to make genome:
RNA dependent RNA polyermase converts ssRNA(+) into ssRNA(-) as a template for generating copies.
RNA dependent RNA polymerase then converts this ssRNA(-) back into ssRNA(+) for the packaging into newly made viruses
explain the structure of the spikes of the rubella virus
trimer of E1 and E2 glycoprotein
how does the rubella virus get into the cell?
receptor mediated endocytosos
in the case of the rubella virus, explain what happens when it affects the host cell, starting with translation
translated into a POLYPROTEIN called p200 which is processed to form p150 and p90.
the combined action of p150 and p90 transcribes the message to make proteins
is the transmission of measles, mumps, and rubella the same or different?
same – all respiratory
measles, mumps, and rubella all result in this symptom:
fever
