The core is composed of a tightly compressed nucleoprotein. To view an electron micrograph of a negatively-stained poxvirus particle click here . Several poxvirus genomes have been sequenced. There is some contribution from the cell but it is not clear what this is - poxvirus gene expression and genome replication occur in enucleated cells, but maturation is blocked. Poxvirus gene expression has been studied in detail because of the interest in the use of Vaccinia virus as a vector for expression of heterologous genes.
Genome replication is believed to involve self-priming, leading to the formation of high m.w.
Inclusions are formed in the cytoplasm which mature into virus particles. Vaccinia virus shows considerable resistance to the antiviral effects of interferons. IL-1 and TNFs. Vaccination was almost universally adopted worldwide around 1800, but it took a major commitment from the WHO in 1965 to achieve eradication. Vaccinia virus is an effective immunogen.