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Molecular dynamics of koala retrovirus infection in captive koalas in Japan

  • Mohammad Enamul Hoque Kayesh
  • Osamu Yamato
  • Mohammad Mahbubur Rahman
  • Md Abul Hashem
  • Fumie Maetani
  • Taiki Eiei
  • Kyoya Mochizuki
  • Hiroko Sakurai
  • Kyoko Tsukiyama-KoharaEmail author
Original Article

Abstract

Koala retrovirus (KoRV) is a gammaretrovirus that is becoming endogenous in koalas. Here, we explored the dynamics of KoRV infection in captive koalas in Japan. We isolated peripheral blood mononuclear cells (PBMCs) from 11 koalas, from which we extracted the KoRV genome. We found the prevalence of KoRV provirus in the koalas to be 100%, and the copy number of KoRV proviral DNA in genomic DNA isolated from PBMCs was variable. The KoRV envelope genes from 11 koalas were sequenced and all were found to be KoRV type A. Nucleotide substitution analysis revealed differences in the KoRV env gene sequences of parents and their offspring. Although no viral KoRV RNA was detected in plasma of healthy koalas, a high copy number was found in plasma of a diseased koala (#6). Hematological analysis showed a high white blood cell (WBC) count in the blood of koala #6. Notably, when retested ~ 5 months later, koala #6 was found to be negative for KoRV in plasma, and the WBC count was within the normal range. Therefore, KoRV in the plasma could be a possible indicator of koala health. We also investigated KoRV growth in concanavalin-A-stimulated koala PBMCs by measuring the KoRV provirus copy number in gDNA and the KoRV RNA copy number in cells and culture supernatants by real-time PCR at days 4, 7, and 14 post-culture. We also observed that KoRV isolates were able to infect HEK293T cells. These findings could enhance our understanding of the dynamics of KoRV and its pathogenesis in koalas.

Notes

Funding

This work was supported by grants from the Ministry of Education, Science, and Culture, Japan.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no competing financial interests.

Ethical approval

This study was done in accordance with institutional committee protocols.

Supplementary material

705_2019_4149_MOESM1_ESM.pdf (661 kb)
Fig. S1 Multiple sequence alignment of partial nucleotide sequences (A) and predicted protein sequences (B) of KoRV env genes isolated from 11 koalas. Specific nucleotide and amino acid changes are indicated by black and red boxes, respectively

References

  1. 1.
    Rasmussen HB (1997) Interactions between exogenous and endogenous retroviruses. J Biomed Sci 4:1–8Google Scholar
  2. 2.
    Gifford R, Tristem M (2003) The evolution, distribution and diversity of endogenous retroviruses. Virus Genes 26:291–315CrossRefGoogle Scholar
  3. 3.
    Bock M, Stoye JP (2000) Endogenous retroviruses and the human germline. Curr Opin Genet Dev 10:651–655CrossRefGoogle Scholar
  4. 4.
    Boeke JD, Stoye JP (1997) Retrotransposons, endogenous retroviruses, and the evolution of retroelements. In: Coffin JM, Hughes SH, Varmus HE (eds) Retroviruses. Cold Spring Harbor, Cold Spring Harbor Laboratory, New York, pp 343–346Google Scholar
  5. 5.
    Hanger JJ, Bromham LD, McKee JJ, O’Brien TM, Robinson WF (2000) The nucleotide sequence of Koala (Phascolactos cinereus) retrovirus: a novel type C endogenous virus related to Gibbon ape leukemia virus. J Virol 74:4264–4272CrossRefGoogle Scholar
  6. 6.
    Tarlinton R, Meers J, Hanger J, Young P (2005) Real-time reverse transcriptase PCR for the endogenous koala retrovirus reveals an association between plasma viral load and neoplastic disease in koalas. J Gen Virol 86:783–787CrossRefGoogle Scholar
  7. 7.
    Denner J, Young PR (2013) Koala retroviruses: characterization and impact on the life of koalas. Retrovirology 10:108CrossRefGoogle Scholar
  8. 8.
    Chaban B, Ong VA, Hanger J, Timms P (2017) Molecular dynamics and mode of transmission of Koala Retrovirus (KoRV) as it invades and spreads through a wild Queensland koala population. J Virol.  https://doi.org/10.1128/JVI.01871-17 Google Scholar
  9. 9.
    Simmons GS, Young PR, Hanger JJ, Jones K, Clarke D, McKee JJ, Meers J (2012) Prevalence of koala retrovirus in geographically diverse populations in Australia. Aust Vet J 90:404–409CrossRefGoogle Scholar
  10. 10.
    Kinney ME, Pye GW (2016) Koala retrovirus: a review. J Zoo Wildl Med 47:387–396CrossRefGoogle Scholar
  11. 11.
    Shaw G, Morse S, Ararat M, Graham FL (2002) Preferential transformation of human neuronal cells by human adenoviruses and the origin of HEK 293 cells. FASEB J 16:869–871CrossRefGoogle Scholar
  12. 12.
    Miyazawa T, Shojima T, Yoshikawa R, Ohata T (2011) Isolation of koala retroviruses from koalas in Japan. J Vet Med Sci 73:65–70CrossRefGoogle Scholar
  13. 13.
    Tarlinton R, Meers J, Young P (2006) Retroviral invasion of the koala genome. Nature 422:79–81CrossRefGoogle Scholar
  14. 14.
    Kumar S, Stecher G, Tamura K (2016) MEGA7: molecular evolutionary genetics analysis version 7.0 for bigger datasets. Mol Biol Evol 33:1870–1874CrossRefGoogle Scholar
  15. 15.
    Xu W, Gorman K, Santiago JC, Kluska K, Eiden MV (2015) Genetic diversity of koala retroviral envelopes. Viruses 7:1258–1270CrossRefGoogle Scholar
  16. 16.
    Shojima T, Hoshino S, Abe M, Yasuda J, Shogen H, Kobayashi T, Miyazawa T (2013) Construction and characterization of an infectious molecular clone of koala retrovirus. J Virol 87:5081–5088CrossRefGoogle Scholar
  17. 17.
    Nitta T, Ha D, Galvez F, Miyazawa T, Fan H (2015) Human and murine APOBEC3s restrict replication of koala retrovirus by different mechanisms. Retrovirology 12:68CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2019

Authors and Affiliations

  • Mohammad Enamul Hoque Kayesh
    • 1
    • 2
    • 3
    • 4
  • Osamu Yamato
    • 5
  • Mohammad Mahbubur Rahman
    • 5
  • Md Abul Hashem
    • 1
    • 3
  • Fumie Maetani
    • 6
  • Taiki Eiei
    • 6
  • Kyoya Mochizuki
    • 6
  • Hiroko Sakurai
    • 6
  • Kyoko Tsukiyama-Kohara
    • 1
    • 2
    • 3
    Email author
  1. 1.Department of Animal Hygiene, Joint Faculty of Veterinary MedicineKagoshima UniversityKagoshimaJapan
  2. 2.Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary ScienceYamaguchi UniversityYamaguchiJapan
  3. 3.Transboundary Animal Diseases Centre, Joint Faculty of Veterinary MedicineKagoshima UniversityKagoshimaJapan
  4. 4.Department of Microbiology and Public HealthPatuakhali Science and Technology UniversityBarishalBangladesh
  5. 5.Department of Clinical Pathology, Joint Faculty of Veterinary MedicineKagoshima UniversityKagoshimaJapan
  6. 6.Hirakawa Zoological ParkKagoshimaJapan

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