Myxoma virus
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Classification: ICTVdB Virus Code: 00.058.1.05.001. Virus accession number: 58105001. Obsolete virus code: 58.1.5.0.001; superceded accession number: 58150001. NCBI Taxon Identifier NCBI Taxonomy ID: 10273. Type of the genus: 00.058.1.05. [1]poripoxvirus]|Leporipoxvirus subfamily 00.058.1. [Chordopoxvirinae]|[2] in the family 00.058. Poxviridae.]
Image: none found.
Natural Host: Lagomorphia, ie. cute little bunny rabbits and hares.
Domain Eucarya, Kingdom Animalia, Phylum Chordata, Subphylum Vertebrata, Class Mammalia, Order Lagomorphia.
Species: Myxoma virus belongs to the genus Leporipoxvirus; subfamily Chondropoxvirinae; family Poxviridae
Genus species Image: not available given copyright restrictions
Description and significance:
Describe the appearance, habitat, etc. of the organism: Myxoma virions have a two complex structures having either an envelope or no envelope, a surface membrane, a core, and lateral bodies. The envelope contains host-derived lipids and self-synthesized glycolipids. In the course of its life cycle, these virions produce both extracellular and intracellular particles. They can have two phenotypes and may be enveloped during their extracellular phase. The extracellular virions initiate viral infection. Myxoma virions may be segregated within non-occluded inclusion bodies. Typically they contain one enveloped nucleocapsid and are slightly pleomorphic, brick–shaped, and measure approximately 250 nm in diameter, 250–300 nm in length, and 200 nm in height. The core is biconcave with two lateral bodies, nested between either the core membrane or the surface membrane. They mature by budding through the membrane of the host cell.
The Myxoma virus was important enough to have its genome sequenced is because it encodes multiple gene products designed to circumvent the host's cellular immune response to the viral infection, thereby inducing extensive immunosuppression in infected rabbits.
Describe how and where it was isolated. The Lausanne strain of the virus was isolated by a team of Canadian scientists at the Department of Microbiology, The University of Western Ontario, London, Ontario, Canada. However, only a partial sequencing of the California MSW strain was achieved by a team associated with School of Biochemistry and Molecular Biology, Faculty of Science, Australian National University, Canberra, Australia. There they cloned EcoRI and SalI restriction fragments of viral DNA and sequenced the ends.
Include a picture or two (with sources) if you can find them. Genome structure Describe the size and content of the genome. The DNA is fully sequenced. Sequence has the accession number [M93049]. The genome is not segmented and consists of a single molecule of linear double-stranded DNA. The complete genome is approximately 161.8 kb long with a central region containing highly conserved enzymatic and structural genes required for essential viral functions. However, peripheral regions within the inverted terminal repeats at both ends of the genome encode nonessential factors that affect host response to infection. These factors include serine proteinase inhibitors, such as SERP1, Serp2, and Serp3, and a scrapin. All of these are located near the right end of the genome and they are responsible for major histo-compatibility complex class I down regulation. The genome has a guanine + cytosine content of approximately 40%e and has termini with cross-linked hairpin ends forming one continuous polynucleotide chain. The genome has terminally redundant sequences which have reiterated inverted terminal sequences that are tandemly repeated. Double-stranded DNA is linked at both ends. [Cheryl Cameron et al. "The Complete DNA Sequence of Myxoma Virus." Virology, Volume 264, Issue 2, 25 November 1999, Pages 298-318].The viral genome encodes structural proteins and non-structural proteins.
How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle? Cell structure and metabolism [edit]
Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces. Ecology [edit]
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc. Pathology [edit]
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms. Application to Biotechnology [edit]
Does this organism produce any useful compounds or enzymes? What are they and how are they used? Current Research [edit]
Enter summaries of the most recent research here--at least three required References [edit]