Rubella virus

from Wikipedia, the free encyclopedia
Rubella virus
Rubella virus TEM B82-0203 lores.jpg

Rubella virus ( TEM image )

Systematics
Classification : Viruses
Area : Riboviria
Empire : Orthornavirae
Phylum : Kitrinoviricota
Class : Alsuviricetes
Order : Hepelivirales
Family : Matonaviridae
Genre : Rubivirus
Type : Rubella virus
Taxonomic characteristics
Genome : (+) ssRNA linear
Baltimore : Group 4
Symmetry : icosahedral
Cover : available
Scientific name
Rubella virus
Short name
RUBV
Left

The rubella virus ( scientifically rubella virus ) is the causative agent of rubella and is the cause of rubella embryo-fetopathy when infected in the first few weeks of pregnancy . Humans are the only known hosts of the virus that can be transmitted by droplet infection .

The rubella virus is the only member of the genus Rubivirus and belongs to the Matonaviridae family (formerly Togaviridae ), the members of which typically have a single-stranded RNA with positive polarity as the genome, which is surrounded by an icosahedral capsid . The RNA genome inside the capsid is approximately 9,757 nucleotides in length and codes for two non-structural proteins and three structural proteins. The capsid protein and the two envelope proteins E1 and E2 make up the three structural proteins.

The molecular basis for the cause of rubella embryopathy is not yet fully understood, but in vitro studies with cell lines have shown that the rubella virus has an apoptotic effect on individual cell types. There is evidence of a p53- dependent mechanism.

morphology

The spherical virus particles of the Matonaviridae have a diameter of 50 to 70 nm and are surrounded by a lipid membrane ( virus envelope ). The heterodimers of the two viral envelope proteins E1 and E2 are embedded in the envelope as distinct spikes (protuberances) 6 nm in height . Inside the lipid shell there is a capsid about 40 nm in size .

Replication

Rubella viruses attach to the cell surface via specific receptors and are taken up by a developing endosome vesicle . At neutral pH outside the cell, the E2 coat protein covers the E1 protein. In the interior of the endosome, the outer domains of the E1 protein are now exposed at acidic pH and the fusion of the endosome membrane and the virus envelope is induced. Thus, the capsid enters the cytosol , disintegrates and releases the genome.
The (+) ssRNA ( positive single- stranded RNA ) initially only serves to translate the non-structural proteins, which are synthesized as a large polyprotein and then cut into individual proteins. The sequences for the structural proteins are first multiplied by the viral RNA polymerase (replicase) using a complementary (-) ssRNA as a template and translated as a separate short mRNA. This short (subgenomic) mRNA is also packaged in the virion.

The translation of the structural proteins also produces a long polypeptide (110  kDa ) that has to be cut into three pieces. The polyprotein is endoproteolytically divided into proteins E1, E2 and capsid protein. E1 and E2 are type I transmembrane proteins whose translocation into the endoplasmic reticulum (ER) takes place with the help of an N-terminal signal sequence. From the ER to the present as a heterodimer E1 · E2 complex passes into the Golgi apparatus , where budding ( budding ) of new virions takes place (in contrast to the Alpha viruses whose budding on the plasma membrane takes place). The capsid proteins, on the other hand, remain in the cytoplasm and attach to the genomic RNA with which they ultimately form the capsid.

Capsid protein

The capsid protein (also protein C) has different functions. The main functions are the formation of homo- oligomers to form the capsid and the binding of the genomic RNA. It is also responsible for the aggregation of the RNA in the capsid, it interacts with the membrane proteins E1 and E2 and binds the human host protein p32, this interaction being important for the virus to multiply in the host. In contrast to alphaviruses, the capsid does not undergo autoprotolysis, but is separated from the rest of the polyprotein by the signal peptidase . The capsid is produced on the surface of the intracellular membranes at the same time as the virus buds.

Reporting requirement

In Germany, direct or indirect evidence of the rubella virus must be reported by name in accordance with Section 7 of the Infection Protection Act (IfSG) if the evidence indicates an acute infection. The obligation to notify primarily concerns the management of laboratories ( § 8 IfSG).

In Switzerland, the positive laboratory analytical finding is a rubella virus laboratory reportable namely after the Epidemics Act (EpG) in connection with the epidemic Regulation and Annex 3 of the Regulation of EDI on the reporting of observations of communicable diseases of man .

literature

  • David M. Knipe, Peter M. Howley (Eds.): Fields' virology . Wolters Kluwer / Lippincott Williams & Wilkins Health, Philadelphia 2013, ISBN 978-1-4511-0563-6 (English).
  • CM Fauquet, MA Mayo et al .: Eighth Report of the International Committee on Taxonomy of Viruses . London / San Diego 2005.

Web links

  • Togaviridae. In: Human Virology at Standord. March 8, 1998(English).;

Individual evidence

  1. a b c ICTV Master Species List 2018b.v1 , MSL # 34
  2. a b c d ICTV: ICTV Master Species List 2019.v1 , New MSL including all taxa updates since the 2018b release, March 2020 (MSL # 35)
  3. Communication from the Standing Vaccination Commission at the RKI - recommendation and scientific justification for the harmonization of the professionally indicated measles, mumps, rubella (MMR) and varicella vaccinations . In: Epidemiological Bulletin . No. 2/2020 . Robert Koch Institute (RKI) , January 9, 2020, p. 3–22 , here p. 6 top right ( rki.de [PDF; 2.8 MB ; accessed on April 2, 2020]).
  4. Dominguez G, Wang CY, Frey TK: Sequence of the genome RNA of rubella virus: evidence for genetic rearrangement during togavirus evolution . In: Virology . 177, No. 1, July 1990, pp. 225-38. PMID 2353453 .
  5. Megyeri K, Berencsi K, Halazonetis TD, et al : Involvement of a p53-dependent pathway in rubella virus-induced apoptosis . In: Virology . 259, No. 1, June 1999, pp. 74-84. doi : 10.1006 / viro.1999.9757 . PMID 10364491 .
  6. Bardeletti G, Kessler N, Aymard-Henry M: Morphology, biochemical analysis and neuraminidase activity of rubella virus . In: Arch. Virol. . 49, No. 2-3, 1975, pp. 175-86. PMID 1212096 .
  7. Togaviridae Classification and Taxonomy . Retrieved February 6, 2011.
  8. Garbutt M, Law LM, Chan H, Hobman TC: Role of rubella virus glycoprotein domains in assembly of virus-like particles . In: J. Virol. . 73, No. 5, May 1999, pp. 3524-33. PMID 10196241 . PMC 104124 (free full text).
  9. Beatch MD, Everitt JC, LJ Law, Hobman TC: Interactions between rubella virus capsid and host protein p32 are important for virus replication . In: J. Virol. . 79, No. 16, August 2005, pp. 10807-20. doi : 10.1128 / JVI.79.16.10807-10820.2005 . PMID 16051872 . PMC 1182682 (free full text).
  10. Beatch MD, Hobman TC: Rubella virus capsid associates with host cell protein p32 and localizes to mitochondria . In: J. Virol. . 74, No. 12, June 2000, pp. 5569-76. PMID 10823864 . PMC 112044 (free full text).