Flavivirus E Protein and NS2B Proteinase Quiz

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Questions and Answers

What is the function of P4 in the context of the text?

It is a structural protein cleaved during translation

It is an RNA dependent RNA polymerase (correct)

It binds to the packaging signal on the genome RNA

It is involved in palmitoylation of structural proteins in the Golgi

Which cellular location are structural proteins directed to during translation?

Endoplasmic reticulum

Lysosomes

Golgi apparatus (correct)

Mitochondria

What is the role of 6K in the context of the text?

It forms nucleocapsid

It is a membrane-associated protein that is palmitoylated (correct)

It is involved in viral genome replication

It interacts with the cytoplasmic tails of envelope proteins studding the plasma membrane

What is the diameter of picornaviruses?

30nm Signup and view all the answers

What is the function of the poly(A) tail in picornavirus RNA?

Stabilizes the RNA molecule Signup and view all the answers

What is the role of the internal ribosome entry site (IRES) in picornavirus RNA?

Allows initiation of translation without a 5’ cap Signup and view all the answers

How many copies of VP4 are present in a mature picornavirus virion?

30 Signup and view all the answers

What is the role of Flavivirus E protein domain III?

Receptor binding Signup and view all the answers

How is RNA synthesis carried out in Flaviviruses?

On membranes in the cytoplasm Signup and view all the answers

How do Flaviviruses enter cells?

Endocytosis within clathrin-coated vesicles Signup and view all the answers

What can antibody-dependent enhancement (ADE) cause in Flavivirus infections?

More severe disease like dengue hemorrhagic fever Signup and view all the answers

What protects Flavivirus E protein from premature conformational change?

Precursor membrane protein (prM) Signup and view all the answers

What is the role of Togavirus glycoproteins E1 and E2?

Receptor binding Signup and view all the answers

What is the genome type of Togaviruses?

'+' sense ssRNA genome Signup and view all the answers

How do Togaviruses enter cells?

Receptor-mediated endocytosis via clathrin-coated vesicles Signup and view all the answers

In Picornaviruses, how are proteins made?

As a single precursor polyprotein, autocatalytically cleaved into capsid proteins and non-structural proteins Signup and view all the answers

What is the role of NS3 protein in Flaviviruses?

Involved in polyprotein cleavage, RNA replication, and possesses nucleoside triphosphate and helicase activities Signup and view all the answers

How does entry of poliovirus RNA into the cytoplasm lead to virion assembly?

Major conformation changes, leading to virion assembly through cleavage of VP0 to VP2 plus VP4 Signup and view all the answers

What is the distinct feature of flavivirus genome organization compared to Togaviruses?

Distinct from Togaviruses despite similar virion morphology and transmission via arthropods Signup and view all the answers

How do Picornaviruses inhibit host cell translation?

Infection causes proteolytic cleavage of eIF-4G, hindering host cell translation Signup and view all the answers

What is the structure of flavivirus virion?

Contains an envelope and 180 copies of M and E (envelope protein heterodimers) arranged with icosahedral symmetry Signup and view all the answers

How does replication of picornavirus RNAs occur?

In a multiprotein complex bound to cellular vesicles, utilizing negative RNA strand as a template for positive-strand synthesis Signup and view all the answers

What is the role of eIF-4G in Picornavirus infection?

Signup and view all the answers

Study Notes

Viral Replication and Translation Processes in Picornaviruses and Flaviviruses

Picornaviruses use cap-dependent translation mechanism, but infection causes proteolytic cleavage of eIF-4G, hindering host cell translation
Picornaviruses hijack cellular translation by binding host cell proteins to internal ribosome entry site (IRES)
Picornavirus proteins are made as a single precursor polyprotein, autocatalytically cleaved into capsid proteins and non-structural proteins
Replication of picornavirus RNAs occurs in a multiprotein complex bound to cellular vesicles, utilizing negative RNA strand as a template for positive-strand synthesis
Entry of poliovirus RNA into the cytoplasm involves major conformation changes, leading to virion assembly through cleavage of VP0 to VP2 plus VP4
Picornavirus infection inhibits host cell functions and leads to the release of newly synthesized virions from the cell
Flaviviruses are transmitted by arthropods and cause important human diseases, with distinct genome organization resembling Picornaviruses
The flavivirus virion contains an envelope and 180 copies of M and E (envelope protein heterodimers) arranged with icosahedral symmetry
Flaviviruses have a linear '+' sense ssRNA genome capped at the 5' end, translated into a single long polyprotein undergoing proteolytic processing
Flavivirus genome organization is distinct from Togaviruses, despite similar virion morphology and transmission via arthropods
Flavivirus RNA structures at the 3' end are cleaved into non-structural and structural proteins, including capsid, prM, M, and NS3 proteins
NS3 protein of Flaviviruses is involved in polyprotein cleavage, RNA replication, and possesses nucleoside triphosphate and helicase activities

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Description

Test your knowledge on Flavivirus E protein and NS2B proteinase, which are essential components for the cleavage of viral polyprotein and receptor binding and membrane fusion. Learn about the structure and function of these viral proteins.