Table of Contents
How do adenoviruses replicate?
Adenoviruses possess a linear dsDNA genome and are able to replicate in the nucleus of vertebrate cells using the host’s replication machinery.
Where do poxviruses replicate?
Poxviruses are large, enveloped viruses that replicate in the cytoplasm and encode proteins for DNA replication and gene expression.
How does smallpox virus replicate?
Upon invasion of a host cell, the smallpox virus replicates in the host cytoplasm, rather than the host nucleus, using many of the host’s own enzymes to replicate.. Replication begins once the virion has reached the cytoplasm of the host cell..
What is the pathogenesis of poxvirus?
The pathogenesis of localized poxvirus infections is simple. Virus invades through broken skin, replicates at the site of inoculation, and causes dermal hyperplasia and leukocyte infiltration.
Is adenovirus lytic or lysogenic?
Species C adenoviruses typically establish a lytic infection in human epithelial cells and produce progeny virus as soon as 12 h postinfection (hpi). During such a lytic infection, cell proliferation ceases and the infected cells die within a few days (2).
How do adenoviruses infect cells?
Adenovirus entry into cells, as defined by experiments with cultured cells, generally involves attachment to a primary receptor, followed by interaction with a secondary receptor responsible for internalization.
Why do poxviruses replicate in the cytoplasm?
Poxviruses replicate in the cell cytoplasm independent of the nucleus and are not dependent upon the cell’s synthetic tools. Thus, the virus employs a panoply of enzymes of its own making to manufacture new progeny virions.
Why poxviruses do not replicate in the cell nucleus?
Poxviruses, a family of large DNA viruses, are unique among DNA viruses, because they carry out DNA replica- tion in the cytoplasm rather than the nucleus.
Where does smallpox replicate in the body?
Smallpox is a double-stranded, 135- to 375-kilobase (kb) DNA virus that replicates in the cytoplasm of the host cell and forms B-type inclusion bodies (Guarnieri bodies). This is in contrast to herpes viruses, which replicate in the nucleus. The orthopoxviruses are among the largest and most complex of all viruses.
How does HPV replicate its genome?
Human papillomavirus (HPV) begins its life cycle by infecting the basal cells of the epithelium. Within these proliferating cells, the viral genomes are replicated, maintained, and passed on to the daughter cells.
What causes poxvirus?
Poxviruses exist throughout the world and cause disease in humans and many other types of animals. Poxvirus infections typically result in the formation of lesions, skin nodules, or disseminated rash. Infection in humans usually occurs due to contact with contaminated animals, people, or materials.
What is the function of adenovirus?
The adenovirus capsid has the job of finding a cell and delivering the viral genome inside. Most of the action occurs at the vertices. The long fibers bind selectively to receptors on the surface of the cell. The most common receptor is CAR, a protein of unknown function that is found on most types of cells.
Which virus replicates in the cytoplasm?
Indeed, poxviruses are DNA viruses that replicate entirely in host cell cytoplasm.
How does poxvirus replicate in the cytoplasm?
This process does not occur randomly, but instead, these viruses create cytoplasmic ‘mini-nuclei’, distinct sites that are surrounded by membranes derived from the rough endoplasmic reticulum (ER) that support viral replication.
Does smallpox affect DNA or RNA?
What is the pathogenesis of smallpox?
Pathogenesis. Smallpox is transmitted to the host via infection by the variola virus . The point of entry for the injection typically resides in the respiratory mucosa although the virus may enter through the skin . Upon infection the virus rapidly advances to the nearby lymph nodes.
When does HPV replicate?
The HPV replication cycle takes at least 3 weeks, as this is the time required for the keratinocyte to undergo complete differentiation cycle. Infection with the high risk human papillomaviruses may lead to pathological changes in the infected tissues, like induction of cervical carcinoma.
How is the poxvirus replicated?
There are about 250 genes in the genome of poxviruses. Replication of the poxvirus is accomplished in several stages. Initially, the virus binds to a receptor present on the surface of host cell. So far the receptors for the poxvirus are not known. Thereafter, the virus enters inside the cell where its uncoating is done in two steps:
How do antivirals target poxvirus DNA replication proteins?
Poxvirus-encoded DNA replication proteins are prime targets for antivirals. Cidofovir and oral derivatives are acyclic nucleoside analogs that are incorporated into the growing DNA strand and inhibit the 5′-to-3′ chain extension and 3′-to-5′ exonuclease activities of poxvirus DNA polymerase (Andrei and Snoeck 2010; Rice et al. 2011).
What is the process of viral replication?
Replication: After the viral genome has been uncoated, transcription or translation of the viral genome is initiated. It is this stage of viral replication that differs greatly between DNA and RNA viruses and viruses with opposite nucleic acid polarity. This process culminates in the de novo synthesis of viral proteins and genome. 5.
What is the self priming model of poxvirus replication?
Self-priming model of poxvirus DNA replication. F and S within the hairpin loops refer to the fast and slow electrophoretic mobilities of DNA fragments containing inverted and complementary hairpin sequences. Dashed lines indicate newly synthesized DNA with arrowheads at the 3′ OH ends.