Herpes simplex virus

As herpes simplex viruses (HSV) are two closely related species of virus from the family Herpesviridae denotes that occur in humans. They belong to the genus simplex virus and were first classified as serotypes of the same species; Virus according to the taxonomy as Human Herpes Virus 1 (HSV -1) and human herpes virus 2 (HSV -2) designated. The herpes simplex viruses cause very different diseases of the herpes simplex, including the so-called oral thrush in infants which the initial infection with. The most common symptoms of infection of these viruses, however, are cold sores (herpes labialis ) and genital herpes ( genital herpes ). The herpes neonatorum of the newborn and the Herpes simplex encephalitis especially in immunocompromised people represent life-threatening complications

Morphology

Herpes simplex viruses consist of a approximately 100 to 110 nm in diameter, large icosahedral capsid. This is about 20 cases of tegument proteins and surrounded by an outer viral envelope; the complete virions are (depending on the study methodology highly variable ) about 140 to 180 nm in size. The capsid is composed of 162 capsomers, of which 150 are in hexagonal symmetry ( hexons ) arranged in twelve pentagonal ( Pentone ). The hexons consist of six molecules of the major capsid VP5 (155 kDa ) and six molecules of the vertex protein VP26; These twelve protein molecules of the hexons are arranged around a central pore around. Three hexons are combined in a triangular symmetry in the structure of proteins VP19c and VP23 are also included. The Pentone consist of five molecules of VP5 and are located at each of the twelve vertices of the icosahedral symmetry. Two other structural proteins are present in small quantities in the capsid: VP24, which has properties of a protease and is responsible for the maturation of the capsid of importance, as well as unclear in its functional gene UL6.

The tegument covering the capsid proteins contain important for gene regulation of the infected cell and the initiation of viral replication, which are not all characterized in their function. Are known VP16, which is also known as αTIF (alpha -trans- inducing factor ), as well as a virion - associated factor UL41, which can inhibit cellular transcription (host shut -off ). To the tegument proteins also include regulatory immediate early protein ( IE) ICP4 and ICP0, and the large subunit of the viral ribonucleotide reductase RR1.

The viral envelope of the herpes simplex virus contains at least ten different viral proteins (mostly glycoproteins ), which are incorporated into a cellular lipid membrane. The coat protein US4 gG shows the differences between the species most HSV-1 and HSV-2 and is responsible for the different serological properties. At least four coat proteins ( gD US6, gL - UL1, UL22 - gH and gB - UL26 ) mediate viral entry into the cell. The sequence of the gB proteins is conserved in a large number of members of the Herpesviridae. The envelope proteins US7 gI and US8 gE form a heterodimer, which provides the direct propagation of the virus between cells, and is capable of binding the Fc portion of IgG antibody.

Genome

The genome consists of a 152 kb large linear double stranded DNA. Correspondence between the nucleotide sequences of HSV-1 and HSV-2 is in most regions of genes, more than 99 %, in the entire sequence about 85%. The differences mainly relate to genes that are involved in the control of viral gene expression or some viral coat proteins. During the virus replication, the linear DNA is a closed ring ( cccDNA ) and may persist in this form in the nucleus. The genome encodes more than 80 open reading frame gene products of more than 100.

System

  • Family Herpesviridae
  • Subfamily Alphaherpesvirinae
  • Genus simplex virus
  • Species herpes simplex virus 1 (HSV -1) or human herpes virus 1 (HHV -1)
  • Species herpes simplex virus 2 (HSV -2) or human herpes virus 2 (HHV -2)
  • Species herpes B virus ( herpesvirus simiae )

Swell

  • CM Fauquet, MA Mayo et al.: Eighth Report of the International Committee on Taxonomy of Viruses. London, San Diego, 2005 ISBN 0-12-249951-4
  • Allan Granoff, Robert G. Webster (eds. ): Encyclopedia of Virology. San Diego, 1999, Volume 2, pp. 677ff ISBN 0-12-227030-4
389221
de