An RNA-dependent RNA polymerase gene in the genomes of bats

2015 Fiscal Year Final Research Report

• Project/Area Number: 26850208
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Integrative animal science
• Research Institution: Kagoshima University
• Principal Investigator: Horie Masayuki 鹿児島大学, 共同獣医学部, 特任助教 (20725981)
• Co-Investigator(Renkei-kenkyūsha): KOBAYASHI Yuki 日本大学, 生物資源科学部, 助教 (30712492) ; AKASAKA Takumi 帯広畜産大学, 畜産学部, 助教 (40748357) ; OGAWA Haruko 帯広畜産大学, 動物・食品衛生研究センター, 教授 (10400079) ; IMAI Kunitoshi 帯広畜産大学, 動物・食品衛生研究センター, 教授 (70374767) ; TOMONAGA Keizo 京都大学, ウイルス研究所, 教授 (10301920)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 内在性ウイルス様エレメント / 共進化 / RNA依存性RNAポリメラーゼ / ボルナウイルス

Outline of Final Research Achievements

Endogenous bornavirus-like L (EBLL) elements are heritable sequences derived from bornavirus L genes that encode a viral RNA-dependent RNA polymerase (RdRp) in eukaryotic genomes. Here, we showed that bats of the genus Eptesicus have preserved for more than 11.8 million years an EBLL element named eEBLL-1, which has an intact open reading frame of more than 5,000 nucleotides. Sequence analysis revealed that functional motifs essential for mononegaviral RdRp activity are well conserved in the EBLL-1 genes. Genetic analyses showed that natural selection operated on eEBLL-1 during the evolution of Eptesicus. We detected efficient transcription of eEBLL-1 in tissues from Eptesicus bats and in cell culture from E. nilssonii that we established. To our knowledge, this study is the first report showing that the eukaryotic genome has gained a riboviral polymerase gene from an ancient virus that has the potential to encode a functional RdRp.

Free Research Field

ウイルス学