Conclusion

Based on this review of studies, the authors postulated that EVE-derived piRNA-guided gene silencing may represent a previously unknown innate immunity against viruses in eukaryotes, in a mechanism parallel to CRISPR-Cas in prokaryotes. However, there is limited experimental evidence which directly shows this mechanism, and thus studies in this field are a high priority. Considering the popularity of gene editing in the current scientific climate, the authors believe that it is necessary to further elucidate the consequences of viral/transposonal gene transfer and piRNA-mediated gene editing.

Glossary

  • Nucleotide:
    a genomic unit that constitutes DNA and RNA.
  • Bornavirus:
    a virus that causes zoonotic diseases, known primarily to cause encephalitis in horses and sheep. Fragments of bornavirus genes integrated into the genome of many mammals, including humans, millions of years ago.
  • Antisense:
    complementary to specific DNA or RNA.
  • Non-coding RNA:
    An RNA that does not encode protein, and functions to regulate target DNA or RNA.
  • Arbovirus:
    general term for viruses that are transmitted via mosquitoes or ticks.
  • Koala retroviruses:
    viruses that causes leukemia and lymphoma in koalas that integrated into the koala genome relatively recently.
  • Prokaryotes:
    organisms that emerged at the very beginning of biological evolution, such as single-celled organisms like bacteria, which have no nucleus and barely exposed DNA within the cell.
  • CRISPR/Cas:
    a system consisting of a repetitive sequence within prokaryotic genome that encodes CRISPR RNA, which binds to the Cas enzyme to target foreign (including viral) RNA and silence them, making an adaptive antiviral immunity.
  • Transposon:
    genes that move within the genome (“the jumping gene”).
Journal information
Title
piRNA-Guided CRISPR-like Immunity in Eukaryotes
DOI:10.1016/j.it.2019.09.003

Authors
Youdiil Ophinni1, Umberto Palatini2, Yoshitake Hayashi1, Nicholas F. Parrish3, 4
  • 1 Division of Molecular Medicine and Medical Genetics, Department of Pathology, Kobe University Graduate School of Medicine
  • 2 Department of Biology and Biotechnology, University of Pavia
  • 3 Genome Immunobiology RIKEN Hakubi Research Team, Cluster for Pioneering Research, RIKEN
  • 4 Center for Integrative Medical Sciences, RIKEN

Journal
Trends in Immunology
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