Identification of novel avian and mammalian deltaviruses provides new insights into deltavirus evolution

Masashi Iwamoto; Yukino Shibata; Junna Kawasaki; Shohei Kojima; Yung-Tsung Li; Shingo Iwami; Masamichi Muramatsu; Hui-Lin Wu; Kazuhiro Wada; Keizo Tomonaga; Koichi Watashi; Masayuki Horie

doi:10.1093/ve/veab003

Identification of novel avian and mammalian deltaviruses provides new insights into deltavirus evolution

Virus Evol. 2021 Feb 12;7(1):veab003. doi: 10.1093/ve/veab003. eCollection 2021 Jan.

Authors

Masashi Iwamoto^{1

2}, Yukino Shibata³, Junna Kawasaki^{4

5}, Shohei Kojima^{4

6}, Yung-Tsung Li⁷, Shingo Iwami², Masamichi Muramatsu¹, Hui-Lin Wu^{7

8}, Kazuhiro Wada⁹, Keizo Tomonaga^{4

5

10}, Koichi Watashi^{1

11}, Masayuki Horie^{4

12}

Affiliations

¹ Department of Virology II, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
² Mathematical Biology Laboratory, Department of Biology, Faculty of Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
³ Graduate School of Life Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo 060-0810, Japan.
⁴ Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan.
⁵ Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan.
⁶ Genome Immunobiology RIKEN Hakubi Research Team, RIKEN Center for Integrative Medical Sciences and RIKEN Cluster for Pioneering Research, 1-7-22, Suehiro-Cho, Tsurumi-Ward, Yokohama 230-0045, Japan.
⁷ Hepatitis Research Center, National Taiwan University Hospital, 7 Chung Shan South Road, Taipei 10002, Taiwan.
⁸ Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, 7 Chung Shan South Road, Taipei 10002, Taiwan.
⁹ Faculty of Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan.
¹⁰ Department of Molecular Virology, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan.
¹¹ Department of Applied Biological Sciences, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Japan.
¹² Hakubi Center for Advanced Research, Kyoto University, 53 Kawahara-cho, Shogo-in, Sakyo, Kyoto 606-8507, Japan.

Abstract

Hepatitis delta virus (HDV) is a satellite virus that requires hepadnavirus envelope proteins for its transmission. Although recent studies identified HDV-related deltaviruses in certain animals, the evolution of deltaviruses, such as the origin of HDV and the mechanism of its coevolution with its helper viruses, is unknown, mainly because of the phylogenetic gaps among deltaviruses. Here, we identified novel deltaviruses of passerine birds, woodchucks, and white-tailed deer by extensive database searches and molecular surveillance. Phylogenetic and molecular epidemiological analyses suggest that HDV originated from mammalian deltaviruses and the past interspecies transmission of mammalian and passerine deltaviruses. Further, metaviromic and experimental analyses suggest that the satellite-helper relationship between HDV and hepadnavirus was established after the divergence of the HDV lineage from non-HDV mammalian deltaviruses. Our findings enhance our understanding of deltavirus evolution, diversity, and transmission, indicating the importance of further surveillance for deltaviruses.

Keywords: deltavirus; inter-species transmission; virome.