Poxviridae: diferenças entre revisões

{{wikiconcurso-grupo2}}

 

The prototype of poxvirus family is vaccinia virus, which has been used as a successful vaccine to eradicate smallpox virus. Vaccinia virus is also used as an effective tool for foreign protein expression to elicite strong host immune response. Vaccinia virus enters cells mainly by cell fusion, although currently the receptor is not known. Virus contains three classes of genes, early, intermediate and late, that are transcribed by viral RNA polymerase and associated transcription factors. Vaccinia virus replicates its genome in cytoplasm of the infected cells and after late gene expression virion morphogenesis produces IMV that contains envelope, although the origin of the envelope membrane is still unknown. IMV is transported to Golgi to be wrapped additional two membrane to become intracellular enveloped virus (IEV). IEV transports along microtubules to reach cell periphery and fuse with plasma membrane to become cell-associated enveloped virus (CEV) that triggers actin tails on cell surfaces or is releared as EEV.

 

The only other poxvirus known to specifically infect humans is the [[molluscum contagiosum|molluscum contagiosum virus]] (MCV).{{fn|3}}

 

The following genera are currently included here:

 

 

==Replicação==

Replication of the poxvirus involves several stages. The first thing the [[virus]] does is to bind to a receptor on the host cell surface; the receptors for the poxvirus are currently unknown. After binding to the receptor, the [[virus]] enters the cell where it uncoats. Uncoating of the [[virus]] is a two step process. Firstly the outer membrane is removed as the particle enters the cell; secondly the [[virus]] particle (without the outer membrane) is uncoated further to release the core into the [[cytoplasm]]. The pox viral [[genes]] are expressed in two phases. The early [[genes]] are expressed first. These [[genes]] the non-structural [[protein]], including [[proteins]] necessary for replication of the viral [[genome]], and are expressed before the [[genome]] is replicated. The late [[genes]] are expressed after the [[genome]] has been replicated and encode the structural [[proteins]] to make the [[virus]] particle. The assembly of the [[virus]] particle occurs in the [[cytoskeleton]] of the cell and is a complex process that is poorly understood but is currently being researched. Considering the fact that this [[virus]] is large and complex replication is relatively quick taking only 12 hours approximately. The replication of this virus is unusual for a [[virus]] with double stranded [[DNA]] [[genome]] because it encodes its own machinery for [[genome]] replication and therefore the replication occurs in the [[cytoplasm]]. Most [[viruses]] with a double stranded [[DNA]] [[genome]] replicate in the [[cell nucleus|nucleus]] and use the host cells [[genome]] replication machinery.

 

*{{fnb|1}}International Committee on Taxonomy of Viruses. [http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/58000000.htm ICTVdb Descriptions: 58. Poxviridae]. Retrieved 2005-02-26.

*{{fnb|2}}[http://www.cellsalive.com/howbig.htm How Big is a ... ?] at ''[http://www.cellsalive.com/index.htm Cells Alive!]''. Retrieved 2005-02-26.

*{{fnb|3}}{{cite journal | title=Pathogenic Molluscum Contagiosum Virus Sequenced | journal=Antiviral Agents Bulletin | month=August | year=1996 | pages=196-7 | publisher=Biotechnology Information Institute | url=http://www.bioinfo.com/mcv.html | accessdate=2006-07-16}}

 

* Buller, R.M.; Palumbo, G.J. (1991). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=1851533 Poxvirus pathogenesis.] ''Microbiological Reviews'' '''55''' (1), 80-122. Full text link provided by [http://www.pubmedcentral.nih.gov/ PubMed Central]. Retrieved 2005-02-27.

* [http://www.poxvirus.org Detailed genomic and bioinformatic information on Poxviruses on NIH-funded database].