An RNA-dependent RNA polymerase gene in bat genomes derived from an ancient negative-strand RNA virus.

Endogenous bornavirus-like L (EBLL) elements are inheritable sequences derived from ancient bornavirus L genes that encode a viral RNA-dependent RNA polymerase (RdRp) in many eukaryotic genomes. Here, we demonstrate 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 1,718 codons. The eEBLL-1 coding sequence 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. Notably, we detected efficient transcription of eEBLL-1 in tissues from Eptesicus bats. To the best of 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.

Citation

Masayuki Horie, Yuki Kobayashi, Tomoyuki Honda, Kan Fujino, Takumi Akasaka, Claudia Kohl, Gudrun Wibbelt, Kristin Mühldorfer, Andreas Kurth, Marcel A Müller, Victor M Corman, Nadine Gillich, Yoshiyuki Suzuki, Martin Schwemmle, Keizo Tomonaga. An RNA-dependent RNA polymerase gene in bat genomes derived from an ancient negative-strand RNA virus. Scientific reports. 2016;6:25873

PMID: 27174689

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