Merkel cell polyomavirus: Difference between revisions

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==Cell structure, metabolism & life cycle==
==Cell structure, metabolism & life cycle==
MCV virus-like particles resemble typical icosahedral polyomavirus capsids that are 55–58 nm diameter. [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2747737/?tool=pmcentrez (5)]  Once they are integrated into the host cell DNA, they lose their ability to replicate independently.  They are typically integrated into the host cell DNA at different locations. [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2747737/?tool=pmcentrez (4)]
MCV virus-like particles resemble typical icosahedral polyomavirus capsids that are 55–58 nm diameter. [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2747737/?tool=pmcentrez (6)]  Once they are integrated into the host cell DNA, they lose their ability to replicate independently.  They are typically integrated into the host cell DNA at different locations. [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2747737/?tool=pmcentrez (5)]


Provide a physical and biochemical description of the organism.  What kind of organism is it, what does it look like, how is it built, what are its metabolic properties, how can it be identified, what is it's life cycle, &c. In other words, describe the organism from <i>its</i> perspective.
Provide a physical and biochemical description of the organism.  What kind of organism is it, what does it look like, how is it built, what are its metabolic properties, how can it be identified, what is it's life cycle, &c. In other words, describe the organism from <i>its</i> perspective.

Revision as of 03:46, 2 November 2011

This student page has not been curated.

A Microbial Biorealm page on the genus Merkel cell polyomavirus

Classification

Virus; dsDNA viruses, no RNA stage; Polyomaviridae; polyomavirus; unclassified polyomavirus (Merkel cell polyomavirus)

Description and significance

Merkel cell polyomavirus is a human tumor virus. It is suspected to be the cause of most cases of a rare skin cancer called Merkel cell carcinoma.

Describe the disease caused by this organism if it is a pathogen, or the natural macroscopic "field guide" appearance and habitat of your organism if it is not. What is or has been the impact your organism on human history or our environment?. How does it do this? How have we harnessed this power, or tried to prevent it? In other words, how do you know it if you see it, and how does its presence influence humans in the present, and historically?

Genome structure

MCV has a 5.4 kbp circular double stranded DNA genome and is a non-enveloped virus. The virus typically integrates at different locations within the human genome in different tumors. Once the virus is integrated into the DNA within the tumor, it cannot be cut out from its host cell. Instead, it must replicate as the host cell replicates. Sequencing of the virus from Merkel cell cancers has revealed this characteristic. The virus typically has tumor-specific mutations that shorten the MCV T antigen. These mutations are the reason why the virus can no longer replicate independently. (3)

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

Cell structure, metabolism & life cycle

MCV virus-like particles resemble typical icosahedral polyomavirus capsids that are 55–58 nm diameter. (6) Once they are integrated into the host cell DNA, they lose their ability to replicate independently. They are typically integrated into the host cell DNA at different locations. (5)

Provide a physical and biochemical description of the organism. What kind of organism is it, what does it look like, how is it built, what are its metabolic properties, how can it be identified, what is it's life cycle, &c. In other words, describe the organism from its perspective.

Ecology (including pathogenesis)

MCV is typically found in about 80% of Merkel cell carcinoma, an agressive neuroendocrine skin cancer linked to lymphoid malignancies such as chronic lymphocytic leukemia. It can also be found in healthy tissues of people without Merkel cell carcinoma. (5) It can also be found in respiratory secretions, suggesting a possible respiratory trasmittance. (1) However, viruses found in Merkel cell carcinoma tumors are nontransmissible because the virsus is integrated into the host DNA and cannot replicate independently. (5) MCV mainly infects elderly people or immunosuppressed individuals, such as AIDS patients (2)

MCV is believed to be the cause of Merkel cell carcinoma tumors that are infected with the virus because inhibition of viral oncoproteins cause cells from the infected tumors to die. Cells from tumors that are not infected with the Merkel cell polyomavirus are not affected by this inhibition. (4)

Describe its habitat, symbiosis, and contributions to environment. If it is a pathogen, how does this organism cause disease? Human, animal, plant hosts? Describe virulence factors and patient symptoms.

Interesting feature

Describe in detail one particularly interesting aspect of your organism or it's affect on humans or the environment.

References

(1) Bialasiewicz S., Lambert S. B., Whiley D. M., Nissen M. D., Sloots T. P. "Merkel cell polyomavirus DNA in respiratory specimens from children and adults." Emerging Infectious Diseases. 2009. Volume 15(3).

(2) Feng, H. Shuda, M., Chang, Y., Moore, P. S. "Clonal Integration of a Polyomavirus in Human Merkel Cell Carcinoma." Science. 2008. Volume 319(5866) p. 1096-1100.

(3) Garneski K. M., DeCaprio J. A., Nghiem, P. "Does a new polyomavirus contribute to Merkel cell carcinoma?" Genome Biology. 2008. Volume 9(6). p. 228.

(4) Shuda, M., Arora, R., Kwun, H. J., Feng, H., Sarid, R., Fernández-Figueras, M. T., Tolstov, Y., Gjoerup, O., Mansukhani, M. M., Swerdlow S. H., Chaudhary, P. M., Kirkwood, J. M., Nalesnik, M. A., Kant, J. A., Weiss, L. M., Moore, P. S., Chang, Y. "Human Merkel cell polyomavirus infection I. MCV T antigen expression in Merkel cell carcinoma, lymphoid tissues and lymphoid tumors." International Journal of Cancer. 2009. Volume 126(6). p. 1243-1249.

(5)

[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.