Question

Enzymes Core Cytoplasm Attach Entry Intermediate mRNA WO TDNA Uncoating DNA replication DNA polymerase Intermediate transcription factors RNA polymerase Envelope Early mRNA Virus factory Late transcription factors Transcription factors Growth factors Immune defense molecules Late mRNA wwwеr Nucleus Concatemer resolution, DNA packaging Microtubules Late enzymes, early transcription factors, structural proteins Wrapping Maturation Actin tails w TGN or early endosomes MV IV Crescents After reviewing the steps of poxvirus replication, name as many unique or interesting aspects of this replication cycle that you feel will be important to remember. Specifically discuss the role of the nucleus during poxvirus replication, and the role of the proteins that the virus brings into the cell packaged in the virion with the genome.

Answer 1

Pox viruses are largest DNA viruses having complex symmetry.A characteristic feature of these viruses is their common ability to induce characteristic “pox” (pockmark) lesions in skin of affected people.

Virus replication

Virus replication begins after fusion of the extracellular enveloped virion with the plasma membrane or after endocytosis and virus core is then released in to the cytoplasm. DNA is very large and can code for more than 200 proteins which includes the enzymes required for transcription and replication of viral genome. Therefore the replication is restricted to cytoplasm itself independently of nucleus. Proteins synthesized will be early and late proteins. There will be encapsulation of virus after late protein synthesis. The virions are released by budding (enveloped virions ) or cell lysis (nonenveloped virions).

The virus can survive in dry scabs even for years. During its pathogenesis the virus will elaborate few virokines which have the property of epidermal growth which will lead to the proliferation of cell leading to hyperkeratinisation and vesicle formation.