How is viral polyprotein processed?
Abstract. The primary translation product of the picornavirus genome is a single large protein which is processed to the mature viral polypeptides by progressive, co- and post-translational cleavages. Replication of the picornaviruses is thus entirely dependent upon the proteolysis of viral precursor proteins.
What is the life cycle of flavivirus?
Flavivirus particles undergo major conformational changes during the life cycle. Some of these changes can be inferred from structural information available for the immature and mature virions as well as the pre-fusion dimer and the post-fusion trimer21,24,25,26,40,71,72,84,85. Virus maturation is a two-step process.
What is polyprotein strategy?
Encoding and translating large viral polyprotein precursors is a strategy with many benefits for the virus lifecycle. First, polyproteins allow for a more compact genome by eliminating additional genetic features, such as promoter or enhancer elements, that would be necessary to express each protein individually.
Which protein is produced by all flavivirus?
The NS2A protein of flavivirus can recruit genomic RNA, structural proteins (C/prM/E), and nonstructural proteins (NS2B/NS3) to the virion assembly site. Once the C-prM-E polyprotein is formed, NS2A will transfer the viral RNA to the structural proteins for virion assembly .
What is nested ORF?
ORFs in S. cerevisiae that may encode nonintronic nested genes were identified by large-scale gene-trapping and strand-specific expression analyses. The putative nested gene is indicated, along with the length of the ORF in codons, its chromosomal start coordinate, and the host gene name.
What is viral Uncoating?
The architecture of a virus particle allows timely release of the viral genome in a host cell during entry. This critical step is known as viral uncoating. It is regulated by cues from receptors, enzymes and chemicals, and facilitated by factors that do not contact the virion directly.
What are the 7 steps of the life cycle of the Flavivirus?
The basic stages of the flavivirus life cycle include attachment to the cell surface, internalization into the host cell, transfer of the viral RNA genome into the cytoplasm, translation of the viral proteins, replication of the genomic RNA, assembly and maturation of the virions, and ultimately the release of progeny …
How does Flavivirus cause yellow fever?
Yellow fever virus is an RNA virus that belongs to the genus Flavivirus. It is related to West Nile, St. Louis encephalitis, and Japanese encephalitis viruses. Yellow fever virus is transmitted to people primarily through the bite of infected Aedes or Haemagogus species mosquitoes.
What is polyprotein gene?
polyprotein. (Science: protein) protein that, after synthesis, is cleaved to produce several functionally distinct polypeptides. Some viruses produce such proteins and some polypeptide hormones seem to be cleaved from a single precursor polyprotein (pro opimelanocortin, for example).
What type of genome do flaviviruses have?
Flaviviridae are small enveloped viruses hosting a positive-sense single-stranded RNA genome. The complete genome is 9500–12,500 nucleotides long.
What is the function of capsid?
A primary function of the capsid is to protect the viral genome from environmental conditions and ultimately to deliver the genome to the interior of a homologous host cell.
What is Polyprotein gene?