Retroviridae: Difference between revisions

From MicrobeWiki, the student-edited microbiology resource
No edit summary
No edit summary
Line 20: Line 20:
==Description and Significance==
==Description and Significance==


 
Retroviruses are viruses that are remarkable for their use of reverse transcription of viral RNA into DNA during replication.  Members of this family include [[Human immunodeficiency virus]] (the virus that causes AIDS), feline leukemia, and several cancer-causing viruses.  Retroviruses were discovered in 1908 by Vilhelm Ellermann and Oluf Bang.  The first sixty years of study of retroviruses focused exclusively on animal infection and disease.  In the 1960s and 1970s, study focused on the viral replication cycle and pathogenic effects at the cellular level.  Current study of retroviruses focuses on the diverse pathogenic effects of these viruses at the cellular and molecular levels.  Retroviruses were the first viruses to be modified for gene therapy, and continue to be used in the majority of gene therapy clinical trials.  (sources: [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowTOC&rid=rv.TOC Coffin et al.], [http://pharmrev.aspetjournals.org/cgi/reprint/52/4/493 Hu and Pathak])


==Genome Structure==
==Genome Structure==
Line 37: Line 37:
==Viral Ecology & Pathology==
==Viral Ecology & Pathology==


The pathogenesis of retrovirus has been concentrated on oncogenesis and more recently AIDS but retroviruses cause a variety of haematopoetic and neurological conditions. Some such conditions caused by retroviridae are paralysis, wasting, ataxia, arthritis, dementia and neuropathy.
 
==References==


It was recently reported that an ancient retrotransposon insertion is the cause of Fukayama-type muscular dystrophy, one of the commonest autosomal recessive disorders in Japan. This is the only known instance of insertional mutagenesis of the human genome caused by this type of element to date, but it seems certain that other examples will be discovered in the future.  
[http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowTOC&rid=rv.TOC Coffin et al.  <u>Retroviruses</u>. Cold Spring Harbor Laboratory Press, 1997.]


==References==
[http://pharmrev.aspetjournals.org/cgi/reprint/52/4/493 Hu, Wei-Shau and Vinay K. Pathak.  "Design of Retroviral Vectors and Helper Cells for Gene Therapy."  ''Pharmacological Reviews'' 52.4 (2000): 493-511.]


[http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.061.htm ICTVdB - The Universal Virus Database, version 4. http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/]
[http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.061.htm ICTVdB - The Universal Virus Database, version 4. http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/]

Revision as of 18:50, 10 July 2006

Baltimore Classification

Higher order taxa

Viruses; Retro-transcribing viruses; Retroviridae

Genera

  • Orthoretrovirinae (subfamily)
    • Alpharetrovirus
    • Betaretrovirus
    • Deltaretrovirus
    • Epsilonretrovirus
    • Gammaretrovirus
    • Lentivirus
  • Spumaretrovirinae (subfamily)
    • Spumaretrovirus
  • Unclassified Retroviridae

Description and Significance

Retroviruses are viruses that are remarkable for their use of reverse transcription of viral RNA into DNA during replication. Members of this family include Human immunodeficiency virus (the virus that causes AIDS), feline leukemia, and several cancer-causing viruses. Retroviruses were discovered in 1908 by Vilhelm Ellermann and Oluf Bang. The first sixty years of study of retroviruses focused exclusively on animal infection and disease. In the 1960s and 1970s, study focused on the viral replication cycle and pathogenic effects at the cellular level. Current study of retroviruses focuses on the diverse pathogenic effects of these viruses at the cellular and molecular levels. Retroviruses were the first viruses to be modified for gene therapy, and continue to be used in the majority of gene therapy clinical trials. (sources: Coffin et al., Hu and Pathak)

Genome Structure

The genome of retroviridae is dimeric, unsegmented and contains a single molecule of linear. The genome is -RT and a positive-sense, single-stranded RNA. Minor species of non-genomic nucleic acid are also found in virions. The encapsidated nucleic acid is mainly of genomic origin but virions may also contain nucleic acid of host origin, including host RNA and fragments of host DNA believed to be incidental inclusions. The complete genome of one monomer is 7000-11000 nucleotides long. The 5'-end of the genome has a methylated nucleotide cap with a cap sequence type 1 m7G5ppp5'GmpNp. The 3'-terminus of each monomer has a poly (A) tract and the terminus has a tRNA-like structure. (source: ICTVdB)

Virion Structure of a Retroviridae

The virions of a retroviridae consist of an envelope, a nucleocapsid and a nucleoid. The virus capsid is enveloped. The virions are spherical to pleomorphic and measure 80-100 nm in diameter. The surface projections are small or distinctive glycoprotein spikes that cover the surface evenly. The projections are densely dispersed and 8 nm long. The nucleoid is concentric or eccentric while the core is spherical. (source: ICTVdB)


Reproduction Cycle of a Retroviridae in a Host Cell

Viral Ecology & Pathology

References

Coffin et al. Retroviruses. Cold Spring Harbor Laboratory Press, 1997.

Hu, Wei-Shau and Vinay K. Pathak. "Design of Retroviral Vectors and Helper Cells for Gene Therapy." Pharmacological Reviews 52.4 (2000): 493-511.

ICTVdB - The Universal Virus Database, version 4. http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/

Retrieved from "https://microbewiki.kenyon.edu/index.php?title=Retroviridae&oldid=4781"