Fundamentals of Molecular Virology

HSV at a glance Family name: Herpesviridae (herpesviruses derive their name from the Greek herpes, meaning “creep”) Subfamilies: Nine human herpesviruses subdivided in the three subfamilies: alpha- beta- gamma-herpesvirinae Herpes simplex viruses 1 and 2 (human herpes virus-1 and -2) Genome: Linear double stranded DNA (about 150 kbp) consists of two covalently linked unique regions UL and US, each bracketed by inverted repeats. One ORIl at midlle of UL sequence, and two Oris at each terminus of Us. The repeats of the L component are designated ab and a’b’. The repeats of the S component are a’c’ and ca. The number of a sequence repeats at the L-S junction and at the L terminus are variable. The genome can be represented as alanb-Ul-b’a’mc’-Us-cas (Fig. 1). Gene products: At least 84 unique transcriptional units (six in two copies) encode 84 proteins (Fig. 1). The genes are classified into kinetic classes as alpha or immediate early, beta or early, and gamma- or late. Six alpha proteins encode transactivators (Table 2) The proteins can be clustered into functional groups (Table 1) Virion morphology: Capsid has icosahedral symmetry, is overlayed by tegument and envelope 6 proteins in capsid – ICP5 is the major capsidic protein 14 protein in tegumant 11 glycoproteins in envelope.