The fact that bats carry and shed highly pathogenic viruses including
The fact that bats carry and shed highly pathogenic viruses including Ebola, Nipah and SARS, they rarely display clinical symptoms of infection. Host factors influencing viral replication are poorly understood in bats and are likely to include both pre- and post-transcriptional regulatory mechanisms. MicroRNAs are a major mechanism of post-transcriptional gene regulation, however very little is known about them in bats. Results: This study describes 399 microRNAs identified by PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/29069523 deep sequencing of small RNA isolated from tissues of the PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28724915 Black flying fox, Pteropus alecto, a confirmed natural reservoir of the human pathogens Hendra virus and Australian bat lyssavirus. Of the microRNAs identified, more than 100 are Chaetocin clinical trials unique amongst vertebrates, including a subset containing mutations in critical seed regions. Clusters of rapidly-evolving microRNAs were identified, as well as microRNAs predicted to target genes involved in antiviral immunity, the DNA damage response, apoptosis and autophagy. Closer inspection of the predicted targets for several highly supported novel miRNA candidates suggests putative roles in host-virus interaction. Conclusions: MicroRNAs are likely to play major roles in regulating virus-host interaction in bats, via dampening of inflammatory responses (limiting the effects of immunopathology), and directly limiting the extent of viral replication, either through restricting the availability of essential factors or by controlling apoptosis. Characterisation of the bat microRNA repertoire is an essential step towards understanding transcriptional regulation during viral infection, and will assist in the identification of mechanisms that enable bats to act as natural virus reservoirs. This in turn will facilitate the development of antiviral strategies for use in humans and other species. Keywords: Bats, Chiroptera, Pteropus alecto, MicroRNA, Non-coding RNA, TranscriptomeBackground More than 20 of all mammalian species are bats, making them an extraordinarily important and successful group from an evolutionary perspective [1]. Bats are unique amongst mammals for their ability to fly, and possess notable traits such as long life expectancy in proportion to body size [2]. Many species of bats exhibit exotic traits including echolocation and hibernation, and bats are an important part of the ecosystem via plant pollination and insect control [3]. Notoriously, bats are also reservoir* Correspondence: [email protected] 1 CSIRO Australian Animal Health Laboratory, 5 Portarlington Rd, Geelong East, Victoria 3220, Australia Full list of author information is available at the end of the articlehosts for a large number of zoonotic viruses [4]. Understanding the mechanisms by which bats co-exist with and seemingly tolerate viruses that are deadly in humans and other mammals has implications for human health, and may facilitate development of new antiviral strategies. One aspect of the bat-virus relationship that has not been investigated in detail is the role of host gene regulation, in particular the role of microRNAs (miRNAs). MiRNAs are essential regulators of eukaryotic gene expression [5] and include elements required for viral replication [6]. MiRNA biogenesis is a multistep process in which primary-miRNA transcripts (pri-miRNA) are cleaved into precursor-miRNA (pre-miRNA) by the nuclear RNase III?2014 Cowled et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons.