HCMVAdapted from Streblow et al. in Cytomegaloviruses
HCMV: Human cytomegalovirus (HCMV) is a prototypic beta-herpesvirus that encodes over 200 predicted open reading frames (ORFs). The mature HCMV virion is 150-200nm in diameter, and composed of a 100nm icosahedral capsid that contains a linear 230kbp double-stranded DNA genome with attached proteins, a large tegument component in comparison to Herpes Simplex Virus (HSV), surrounded by the envelope that contains a cellular lipid bilayer with viral glycoproteins. A number of the viral and cellular proteins that compose an HCMV virion have been identified by biochemical and immunological approaches. These methods generally are limited to the identification of single abundant species of protein using immunological methods with specific antibodies. However, other approaches have included the sequencing of peptides from disrupted HCMV particles separated on gels.
HCMV infected cells generate three different types of particles including infectious mature virions described above, non-infectious enveloped particles (NIEPs), and dense bodies (DBs). NIEPs are composed of the same viral proteins as infectious virions and possess a capsid but lack viral DNA. So, by electron microscopy they can be distinguished from mature virions by their lack of an electron dense DNA core. DBs are uniquely characteristic of HCMV and simian CMV infections and are non-replicating, fusion-competent enveloped particles composed primarily of the tegument protein pp65 (UL83). The quantities of these different HCMV particles are dependent on the viral strain and the multiplicity of infection. MCMV infected cells do not produce DBs, instead, this virus forms multi-capsid virions, which are not observed in HCMV-infected cells.
Human Cytomegalovirus Genomics
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