Department of Microbiology

Research activities

Research Overview

Our laboratory focuses on the molecular biology of RNA viruses, with a particular emphasis on rotavirus genetics, virus–host interactions, and emerging zoonotic viruses. By integrating reverse genetics, cell biology, animal models, and field surveillance, we aim to uncover fundamental mechanisms of viral infection and develop new strategies for prevention and control.

1. Rotavirus Reverse Genetics and Viral Pathogenesis
   Rotavirus remains a leading cause of severe gastroenteritis in infants and young children worldwide. Our laboratory has established an advanced plasmid-based reverse genetics system, enabling precise manipulation of all 11 genome segments. This technology allows us to dissect gene function in unprecedented detail and to generate recombinant viruses for both basic and translational research.
2. Intestinal Microbiota–Virus Interactions
   The gastrointestinal tract harbors a complex microbial ecosystem that profoundly influences enteric viral infections. We study how intestinal bacteria, metabolites, and epithelial cell gene expression regulate rotavirus and other enteric viruses.
3. Zoonotic Virus Surveillance and Wildlife Virome
   Emerging viruses frequently originate from wildlife, yet many remain uncharacterized. In collaboration with partners in Southeast Asia, we conduct field-based zoonotic virus surveillance, focusing on mammals such as bats, primates, and rodents.
4. Molecular mechanisms of replication of praramyxoviruses
   The family Paraxyoviridae contains many well-known human and animal pathogens, such as human parainfluenza virus type (PIV) 1-4, measles virus, mumps virus, Sendai virus, Nipah virus, and RS virus. We have been studying PIV2, PIV5, SV41, and Sendai virus, using reverse genetics and other methods.
   To explore the mechanisms of viral growth, we are currently conducing the following projects.
   1. Identification of cellular proteins that interact with viral proteins.
   2. Functional studies of each viral protein.
   3. Molecular mechanisms of immune system inhibited by viral proteins.
   4. Development of highly efficient reverse genetics system for negative-strand RNA viruses.

Members

Graduate Students Wanted

We are seeking enthusiastic graduate students who wish to pursue advanced research in virology, including rotavirus reverse genetics, intestinal microbiota–virus interactions, and zoonotic virus surveillance.
We offer a highly supportive research environment, state-of-the-art facilities, and opportunities for international collaboration.
Students funded by Japanese Government (MEXT) Scholarships or other programs are welcome to apply.

If you are passionate about scientific discovery and wish to join our lab, please contact:
Yuta Kanai, DVM, PhD
Email: y-kanai@wakayama-med.ac.jp

Recent Publications

• Ohta K, Kawasaki J, Kolakofsky D, Nishio M, Matsumoto Y. Evidence that hPIV2 paramyxovirus antigenomes are edited during infection. mBio. 16:e0366724.(2025)
• Ohta K, Saka N, Nishio M. Identification of critical residues for RNA binding of nairovirus nucleoprotein. J Virol. 98:e0144624.(2024)
• Saka N, Nishio M, Ohta K. Human parainfluenza virus type 2 V protein inhibits mitochondrial apoptosis pathway through two ways. Virology. 594:110053. (2024)
• Kanai Y, Kotaki T, Sakai S, Ishisaka T, Matsuo K, Yoshida Y, Hirai K, Minami S, and Kobayashi T. Rapid production of recombinant rotaviruses by overexpression of NSP2 and NSP5 genes with modified nucleotide sequences. J Virol 98(12):e0099624 (2024)
• Ohta K, Saka N, Nishi Y, Nishio M. Nairovirus polymerase mutations associated with the establishment of persistent infection in human cells. J Virol. 98:e0169823. (2024)
• Saka N, Ohta K, Kolakofsky D, Nishio M. The bipartite promoter of Orthonairovirus hazaraense large segment. J Virol. 97:e0091823. (2023)
• Kanai Y, Onishi M, Yoshida Y, Kotaki T, Minami S, Nouda R, Yamasaki M, Enoki Y, and Kobayashi T. Genetic engineering strategy for generating a stable dsRNA virus vector using a virus-like codon-modified transgene. J Virol 97(10):e0049223 (2023)
• Yamasaki M, Kanai Y, Wakamura Y, Kotaki T, Minami S, Nouda R, Nurdin JA, Kobayashi T. Characterization of Sialic Acid-Independent Simian Rotavirus Mutants in Viral Infection and Pathogenesis. Journal of Virology 97 :e0139722. (2023)
• Ohta K, Saka N, Fukasawa M, Nishio M. Hazara orthonairovirus nucleoprotein facilitates viral cell-to-cell spread by modulating tight junction protein, claudin-1. Front Microbiol. 14:1192956. (2023)
• Ohta K, Saka N, Nishio M. Hazara orthonairovirus nucleoprotein antagonizes type I interferon production by inhibition of RIG-I ubiquitination. Viruses. 14:1965. (2022)
• Saka N, Matsumoto Y, Ohta K, Kolakofsky D, Nishio M. A point mutation in the human parainfluenza virus type 2 nucleoprotein leads to two separate effects on virus replication. J Virol. 96:e0206721. (2022)
• Kolakofsky D, Le Mercier P, Nishio M, Blackledge M, Crépin T, Ruigrok RWH. Sendai virus and a unified model of mononegavirus RNA synthesis. Viruses. 13:2466. (2021)
• Ohta K, Saka N, Nishio M. Human parainfluenza virus type 2 V protein modulates iron homeostasis. J Virol. 95:e01861-20. (2021)
• Ohta K, Matsumoto Y, Nishio M. Common and unique mechanisms of filamentous actin formation by viruses of the genus Orthorubulavirus. Arch Virol. 165:799-807. (2020)
• Ohta K, Matsumoto Y, Nishio M. Inhibition of Cavin3 degradation by the human parainfluenza virus type 2 V protein is important for efficient viral growth. Front Microbiol. 11:803. (2020)
• Ohta K, Matsumoto Y, Nishio M. Profilin2 is required for filamentous actin formation induced by human parainfluenza virus type 2. Virology. 533:108-114. (2019)
• Matsumoto Y, Ohta K, Nishio M. Importance of tyrosine in the RNA-binding domain of human parainfluenza virus type 2 nucleoprotein for polymerase activity. Arch Virol. 164:1851-1855. (2019)
• Matsumoto Y, Nouchi T, Ohta K, Nishio M. Regulation of Hazara virus growth through apoptosis inhibition by viral nucleoprotein. Arch Virol. 164:1597-1607. (2019)
• Yumine N, Matsumoto Y, Ohta K, Fukasawa M, Nishio M. Claudin-1 inhibits human parainfluenza virus type 2 dissemination. Virology. 531:93-99. (2019)
• Matsumoto Y, Ohta K, Kolakofsky D, Nishio M. A minigenome study of Hazara nairovirus genomic promoters. J Virol. 93:e02118-18. (2019)
• Ohtsuka J, Matsumoto Y, Ohta K, Fukumura M, Tsurudome M, Nosaka T, Nishio M. Nucleocytoplasmic shuttling of human parainfluenza virus type 2 phosphoprotein. Virology. 528:54-63. (2019)
• Ohta K, Matsumoto Y, Yumine N, Nishio M. The V protein of human parainfluenza virus type 2 V protein promotes RhoA-induced filamentous actin formation. Virology. 524:90-96. (2018)
• Ohta K, Matsumoto Y, Nishio M. Human parainfluenza virus type 2 V protein inhibits caspase-1. J Gen Virol. 99:501-511. (2018)
• Ohta K, Matsumoto Y, Nishio M. Rab27a facilitates human parainfluenza virus type 2 growth by promoting cell surface transport of envelope proteins. Med Microbiol Immunol. 207:141-150. (2018)
• Matsumoto Y, Ohta K, Kolakofsky D, Nishio M. The control of paramyxovirus genome hexamer length and mRNA editing. RNA. 24:461-467. (2018)
• Matsumoto Y, Ohta K, Nishio M. Lethal infection of embryonated chicken eggs by Hazara virus, a model for Crimean-Congo hemorrhagic fever virus. Arch Virol. 163:219-222. (2018)
• Tsurudome M, Ohtsuka J, Ito M, Nishio M, Nosaka T. The hemagglutinin-neuraminidase (HN) head domain and the fusion (F) protein stalk domain of the parainfluenza viruses affect the specificity of the HN-F interaction. Front Microbiol. 9:391. (2018)
• Matsumoto Y, Ohta K, Nishio M. Human parainfluenza virus type 2 polymerase complex recognizes leader promoters of other species belonging to the genus Rubulavirus. Med Microbiol Immunol. 206:441-446. (2017)
• Ohta K, Matsumoto Y, Ito M, Nishio M. Tetherin antagonism by V proteins is a common trait among the genus Rubulavirus. Med Microbiol Immunol. 206:319-326. (2017)
• Ohta K, Matsumoto Y, Yumine N, Nishio M. Human parainfluenza virus type 2 V protein inhibits induction of tetherin. Med Microbiol Immunol. 206:311-318. (2017)
• Matsumoto Y, Ohta K, Kolakofsky D, Nishio M. A point mutation in the RNA-binding domain of human parainfluenza virus type 2 nucleoprotein elicits abnormally enhanced polymerase activity. J Virol. 91: e02203-16. (2017)

Undergraduate

• School of Medicine
  • Message from the Dean
  • List of Medicine
• School of Health and Nursing Science
  • Message from the Dean
• School of Pharmaceutical Sciences
  • Message from the Dean

pagetop