Hamster polyomavirus

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Mesocricetus auratus polyomavirus 1
Virus classification Edit this classification
(unranked): Virus
Realm: Monodnaviria
Kingdom: Shotokuvirae
Phylum: Cossaviricota
Class: Papovaviricetes
Order: Sepolyvirales
Family: Polyomaviridae
Genus: Alphapolyomavirus
Mesocricetus auratus polyomavirus 1

Hamster polyomavirus (abbreviated HaPyV or HaPV,[note 1][1] officially known as Mesocricetus auratus polyomavirus 1[2]) is an unenveloped double-stranded DNA virus of the polyomavirus family whose natural host is the hamster. It was originally described in 1967 by Arnold Graffi as a cause of epithelioma in Syrian hamsters (Mesocricetus auratus).[3][4]

Genome and taxonomy[edit]

The organization of the HaPyV genome is typical of polyomaviruses. At around 5.3 kilobase pairs in length, it contains genes for the small, middle, and large tumor antigens and three viral coat proteins, VP1, VP2, and VP3.[3] In the 2015 taxonomic update to the polyomavirus group, the International Committee on Taxonomy of Viruses classified HaPyV in the genus Alphapolyomavirus, whose type species is mouse polyomavirus (MPyV).[2]

HaPyV and MPyV are closely genetically related; until recently, they were the only two members of the polyomavirus family known to express the middle tumor antigen protein, which is uniquely efficient at inducing neoplastic transformation in infected cells, resulting in transformation in in vitro cell culture and in the formation of tumors in vivo.[5] In 2015 the genome sequence of a rat polyomavirus was reported to contain middle tumor antigen as well,[6] consistent with expectations that it evolved uniquely in the rodent lineage of the polyomavirus family.[7] However, middle tumor antigen has also recently been reported in at least one virus of unrelated lineage, the trichodysplasia spinulosa polyomavirus, which is a normally asymptomatic infection in humans that sometimes causes trichodysplasia spinulosa in immunocompromised individuals.[8]


Following the typical pattern for polyomaviruses, the HaPyV viral capsid contains three proteins: VP1, VP2, and VP3, of which VP1 is the primary component. VP1 monomers assemble into a closed icosahedral structure. However, the HaPyV capsid differs from its close relative MPyV and from another well-studied polyomavirus, SV40, in having a T=7 levo rather than dextro symmetry.[9]

Infection and clinical manifestations[edit]

Hamster polyomavirus was originally identified in hamster epithelial tumors, where virus particles can be readily detected. When the virus is injected into juvenile hamsters from naive populations, it induces leukemias and lymphomas which are free of virus particles but whose cells contain extra-chromosomal viral DNA.[3][10] This observation is in contrast to the skin tumors, which carry substantial viral loads.[3] The capacity to induce hematopoietic tumors is unusual for polyomaviruses[1][3] and may be associated with the properties of the HaPyV middle tumor antigen.[11]

HaPyV has primarily been reported in research colonies; it appeared apparently spontaneously in the colony from which it was first described and in which it became enzootic.[3] It was also identified in a 2001 case report as naturally occurring in a pet Syrian hamster.[12] It is shed in urine and this is believed to be the mechanism for transmission, similar to what is observed in mouse polyomavirus. While many known hamster viruses are clinically inapparent, HaPyV (along with hamster parvovirus) is unusual in causing clinically significant disease.[1] The virulence of HaPyV in Syrian hamsters may be due to cross-species transmission from the European hamster, most likely the natural host.[10]


  1. ^ This was the historically common abbreviation; however, it is ambiguous because it is also used for hamster parvovirus.


  1. ^ a b c Suckow, Mark A.; Stevens, Karla A.; Wilson, Ronald P. (2012). The laboratory rabbit, guinea pig, hamster, and other rodents (1st ed.). Amsterdam: Elsevier Academic Press. p. 822. ISBN 978-0-12-380920-9.
  2. ^ a b Polyomaviridae Study Group of the International Committee on Taxonomy of, Viruses; Calvignac-Spencer, S; Feltkamp, MC; Daugherty, MD; Moens, U; Ramqvist, T; Johne, R; Ehlers, B (29 February 2016). "A taxonomy update for the family Polyomaviridae". Archives of Virology. 161 (6): 1739–50. doi:10.1007/s00705-016-2794-y. hdl:10037/13151. PMID 26923930.
  3. ^ a b c d e f Scherneck, S; Ulrich, R; Feunteun, J (January 2001). "The hamster polyomavirus--a brief review of recent knowledge". Virus Genes. 22 (1): 93–101. doi:10.1023/A:1008190504521. PMID 11210944. S2CID 13698088.
  4. ^ Graffi, A; Schramm, T; Graffi, I; Bierwolf, D; Bender, E (April 1968). "Virus-associated skin tumors of the Syrian hamster: preliminary note". Journal of the National Cancer Institute. 40 (4): 867–73. doi:10.1093/jnci/40.4.867. PMID 5646499.
  5. ^ Fluck, MM; Schaffhausen, BS (September 2009). "Lessons in signaling and tumorigenesis from polyomavirus middle T antigen". Microbiology and Molecular Biology Reviews. 73 (3): 542–63, Table of Contents. doi:10.1128/mmbr.00009-09. PMC 2738132. PMID 19721090.
  6. ^ Ehlers, B; Richter, D; Matuschka, FR; Ulrich, RG (3 September 2015). "Genome Sequences of a Rat Polyomavirus Related to Murine Polyomavirus, Rattus norvegicus Polyomavirus 1". Genome Announcements. 3 (5): e00997–15. doi:10.1128/genomeA.00997-15. PMC 4559740. PMID 26337891.
  7. ^ Gottlieb, KA; Villarreal, LP (June 2001). "Natural biology of polyomavirus middle T antigen". Microbiology and Molecular Biology Reviews. 65 (2): 288–318, second and third pages, table of contents. doi:10.1128/mmbr.65.2.288-318.2001. PMC 99028. PMID 11381103.
  8. ^ van der Meijden, Els; Kazem, Siamaque; Dargel, Christina A.; van Vuren, Nick; Hensbergen, Paul J.; Feltkamp, Mariet C. W.; Imperiale, M. J. (15 September 2015). "Characterization of T Antigens, Including Middle T and Alternative T, Expressed by the Human Polyomavirus Associated with Trichodysplasia Spinulosa". Journal of Virology. 89 (18): 9427–9439. doi:10.1128/JVI.00911-15. PMC 4542345. PMID 26136575.
  9. ^ Siray, Hassen; O¨zel, M.; Jandrig, B.; Voronkova, T.; Jia, W.; Zocher, R.; Arnold, W.; Scherneck, S.; Kru¨ger, D. H.; Ulrich, R. (1999). "Capsid Protein-Encoding Genes of Hamster Polyomavirus and Properties of the Viral Capsid". Virus Genes. 18 (1): 39–47. doi:10.1023/A:1008017201999. PMID 10334036. S2CID 35407503.
  10. ^ a b Barthold, Stephen W.; Griffey, Stephen M.; Percy, Dean H. (2016). Pathology of Laboratory Rodents and Rabbits (4th ed.). John Wiley & Sons. p. 176. ISBN 978-1-118-92403-7.
  11. ^ Courtneidge, SA; Goutebroze, L; Cartwright, A; Heber, A; Scherneck, S; Feunteun, J (June 1991). "Identification and characterization of the hamster polyomavirus middle T antigen". Journal of Virology. 65 (6): 3301–8. doi:10.1128/JVI.65.6.3301-3308.1991. PMC 240988. PMID 1709702.
  12. ^ Simmons, JH; Riley, LK; Franklin, CL; Besch-Williford, CL (July 2001). "Hamster polyomavirus infection in a pet Syrian hamster (Mesocricetus auratus)". Veterinary Pathology. 38 (4): 441–6. doi:10.1354/vp.38-4-441. PMID 11467479.