Mason pfizer monkey virus

A Microbial Biorealm page on the genus Mason pfizer monkey virus

Classification

Higher order taxa

Viruses; Retro-transcribing viruses; Retroviridae; Orthoretrovirinae; Betaretrovirus NCBI

Species

Genus species: Mason Pfizer Monkey Virus

NCBI: Taxonomy

Description and significance

Describe the appearance, habitat, etc. of the organism, and why you think it is important.

Mason Pfizer Monkey virus (MPMV) is the prototype virus of the type D retroviruses and was observed by Harish C. Chopra and Marcus M. Mason in 1970 (Chopra and Mason, 1970). MPMV is a retrovirus of primate origin which has properties similar to the type C and type B viruses, but is morphologically distinct (Fine and Schochetman, 1978). The virus contains intracellular ring-shaped, 60 to 95 nanometers in diameter A-type particles near the plasma membrane, as well as extracellular mature particles with an oval spherical outer unit membrane measuring 100 to 120 nanometers in diameter with an electron-dense sphere or a rod-shaped nucleoid 30 to 50 m/j in diameter.

Genome structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence?

ssRNA; linear; Length: 8,557 nt Replicon Type: viral segment Four protein coding genes, Two non protein coding genes. Three gag-pro-pol-env, MPMVgp1, with protein products: Pr95, DU, RT-IN, gp70 SU, gp20 TM, and p12 PR. NC_001550 RT-IN - RT_Rtv: Reverse transcriptases (RTs) from retroviruses (Rtvs). RTs catalyze the conversion of single-stranded RNA into double-stranded viral DNA for integration into host chromosomes. Proteins in this subfamily contain long terminal repeats (LTRs) and are multifunctional enzymes with RNA-directed DNA polymerase, DNA directed DNA polymerase, and ribonuclease hybrid (RNase H) activities. The viral RNA genome enters the cytoplasm as part of a nucleoprotein complex, and the process of reverse transcription generates in the cytoplasm forming a linear DNA duplex via an intricate series of steps. This duplex DNA is colinear with its RNA template, but contains terminal duplications known as LTRs that are not present in viral RNA. It has been proposed that two specialized template switches, known as strand-transfer reactions or "jumps", are required to generate the LTRs. PMID 9831551

Reverse transcriptase thumb domain. This domain is known as the thumb domain. It is composed of a four helix bundle. PMID:1377403

Retroviral aspartyl protease. Single domain aspartyl proteases from retroviruses, retrotransposons, and badnaviruses (plant dsDNA viruses). These proteases are generally part of a larger polyprotein; usually pol, more rarely gag. Retroviral proteases appear to be homologous to a single domain of the two-domain eukaryotic aspartyl proteases such as pepsins, cathepsins, and renins (pfam00026)-Marchler-Bauer A, Anderson JB, Derbyshire MK, DeWeese-Scott C, Gonzales NR, Gwadz M, Hao L, He S, Hurwitz DI, Jackson JD, Ke Z, Krylov D, Lanczycki CJ, Liebert CA, Liu C, Lu F, Lu S, Marchler GH, Mullokandov M, Song JS, Thanki N, Yamashita RA, Yin JJ, Zhang D, Bryant SH. (2007) CDD: a conserved domain database for interactive domain family analysis. Nucleic Acids Res. 35: D237-40

RnaseH; RNase H. RNase H digests the RNA strand of an RNA/DNA hybrid. Important enzyme in retroviral replication cycle, and often found as a domain associated with reverse transcriptases. Structure is a mixed alpha+beta fold with three a/b/a layers. -Marchler-Bauer A, Anderson JB, Derbyshire MK, DeWeese-Scott C, Gonzales NR, Gwadz M, Hao L, He S, Hurwitz DI, Jackson JD, Ke Z, Krylov D, Lanczycki CJ, Liebert CA, Liu C, Lu F, Lu S, Marchler GH, Mullokandov M, Song JS, Thanki N, Yamashita RA, Yin JJ, Zhang D, Bryant SH. (2007) CDD: a conserved domain database for interactive domain family analysis. Nucleic Acids Res. 35: D237-40

Integrase Zinc binding domain. Integrase mediates integration of a DNA copy of the viral genome into the host chromosome. Integrase is composed of three domains. This domain is the amino-terminal domain zinc binding domain. The central domain is the catalytic domain pfam00665. The carboxyl terminal domain is a DNA binding domain pfam00552. PMID: 9228950

Integrase DNA binding domain. Integrase mediates integration of a DNA copy of the viral genome into the host chromosome. Integrase is composed of three domains. The amino-terminal domain is a zinc binding domain. The central domain is the catalytic domain pfam00665. This domain is the carboxyl terminal domain that is a non-specific DNA binding domain. PMID: 7632683

Pr95 -

gp20 TM - ENV polyprotein (coat polyprotein). - Marchler-Bauer A, Anderson JB, Derbyshire MK, DeWeese-Scott C, Gonzales NR, Gwadz M, Hao L, He S, Hurwitz DI, Jackson JD, Ke Z, Krylov D, Lanczycki CJ, Liebert CA, Liu C, Lu F, Lu S, Marchler GH, Mullokandov M, Song JS, Thanki N, Yamashita RA, Yin JJ, Zhang D, Bryant SH. (2007) CDD: a conserved domain database for interactive domain family analysis. Nucleic Acids Res. 35: D237-40 - gag gene protein p24 (core nucleocapsid protein). p24 forms inner protein layer of the nucleocapsid. ELISA tests for p24 is the most commonly used method to demonstrate virus replication both in vivo and in vitro. PMID: 9245608

gp70 SU - ENV polyprotein (coat polyprotein)- Marchler-Bauer A, Anderson JB, Derbyshire MK, DeWeese-Scott C, Gonzales NR, Gwadz M, Hao L, He S, Hurwitz DI, Jackson JD, Ke Z, Krylov D, Lanczycki CJ, Liebert CA, Liu C, Lu F, Lu S, Marchler GH, Mullokandov M, Song JS, Thanki N, Yamashita RA, Yin JJ, Zhang D, Bryant SH. (2007) CDD: a conserved domain database for interactive domain family analysis. Nucleic Acids Res. 35: D237-40

One gag gene, MPMVgp2, with protein products: Pr78, p14 NC, p10 MA, p24, p12, and p 27. NC_001550

Retroviral GAG p10 protein. This family consists of various retroviral GAG (core) polyproteins and encompasses the p10 region producing the p10 protein upon proteolytic cleavage of GAG by retroviral protease. The p10 or matrix protein (MA) is associated with the virus envelope glycoproteins in most mammalian retroviruses and may be involved in virus particle assembly, transport and budding. Some of the GAG polyproteins have alternate cleavage sites leading to the production of alternative and longer cleavage products (e.g. p19) the alignment of this family only covers the approximately N-terminal (GAG) 100 amino acid region of homology to p10. PMID: 9094640

Non protein coding genes pro, MPMVgp3, and pol, MPMVgp4. NC_001550

The Mr of the genome constitutes 2% of the virion by weight. The genome is dimeric; not segmented; consists of { } { } a single molecule of; { }linear; { }positive-sense; { }single-stranded; { }RNA. The complete genome is of one monomer 8000 nucleotides long. { }Has been fully sequenced; { } with the accession number [[http:]www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=*****] [M12349]. The genome has terminally redundant sequences. The terminally redundant sequences have long terminal repeats (LTR) (of about 350 nt). The 5'–end of the genome has a cap; cap is a methylated nucleotide cap; cap sequence type is of type 1 m7G5ppp5'GmpNp. The 3'–terminus has of each monomer a poly (A) tract. The 3'–terminus has a tRNA–like structure (and accepts lysin). http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/

Virion Structure

Interesting features of cell structure; how it gains energy; what important molecules it produces.

2 types of particles, viz., an intracytoplasmic, electron-dense, ring-shaped particle measuring about 70 m/u in diameter, and an extracellular particle with an outer unit membrane and a central dense nucleoid measuring about 110 m/n in diameter. (Mason, 1970)

Betaretrovirus contains unique D type structural retroviruses, similar yet distinguished morphology from type C retrovirus and type B retrovirus. Less dense knob shaped surface spikes, tubular nucleoid region. Requires host cells for metabolism Type D is also distinguished by accumulation of type A intracellular particles and budding release.

Virions{ }; have a complex construction; { } and consist of an envelope, a nucleocapsid, and a nucleoid. Virus capsid (core) is enveloped. Virions are spherical to pleomorphic; measure 80–100 nm in diameter. The surface projections are small { }; { } spikes { }; { } evenly covering the surface. They are { } densely dispersed. The core is spherical. The nucleoid is eccentric. http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/

Proteins constitute about 60% of the particle weight. The viral genome encodes structural proteins and non-structural proteins.

Non-Structural Proteins: The virus codes for an RNA-dependent DNA polymerase

Lipids are present; { } and are located in the envelope. Virions are composed of 35% lipids by weight. The composition of viral lipids and host cell membranes are similar. The lipids are of host origin; { }{ } are derived from plasma membranes.

the intracytoplasmic development and virus maturation by a process of budding at the level of the cell membrane

By itself, genomic nucleic acid is not infectious.

Translation: Replication involves a reverse transcription step.

Ecology

Habitat; symbiosis; contributions to the environment.

Mason Pfizer monkey virus was first isolated from mammary breast carcinoma in rhesus monkey, and old world monkey. Virus isolates maintain infectious in other old world monkeys such as langur monkeys, new world monkeys, as well as isolate type D retroviruses from humans; this retrovirus infects rhesus monkeys body temperature 36-40 degrees C Human 36.9. This slight fluctuation of temperature indicates this virus requires mesophillic conditions (15 and 40 °C)in a host.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Induces fatal immune suppression by attacking T-lymphocyte cells in mammalian hosts. Newborns treated with MPMV - Older monkeys with MPMV-

Virus infects during its life cycle a single type of vertebrate host. Viral hosts belong to the Domain Eucarya.

Domain Eucarya Kingdom Animalia.

Kingdom Animalia Phylum Chordata.

Phylum Vertebrata Subphylum Vertebrata.

Class Mammalia.

Class Mammalia Order Primates. http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/

Isolate abundance in healthy rhesus monkeys

Symptoms

Current Research

Enter summarries of the most rescent research here--at least three required

1) MPMV as a vector

2) Ancestral relations, origins

3)

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Emily Lilly at University of Massachusetts Dartmouth.