BACTERIAL GENETICS

A function for retrons

Retrons are bacterial genomic elements encoding a reverse transcriptase and a non-coding RNA (ncRNA). Despite their discovery more than three decades ago, the function of retrons remains unknown. Millman et al. found that many retrons are in close proximity in the genome to known phage-defence systems, suggesting that they are also involved in defence against phage infection. Retrons form a cassette that includes a reverse transcriptase, ncRNA and one or two genes encoding proteins that might function as effectors. Introduction of retrons and their effectors into an Escherichia coli strain lacking retrons provided defence against infection by various phages, by growth arrest or cell death. The authors showed that the defence mechanism of one retron involved sensing phage-mediated inactivation of the phage DNA-degrading RecBCD complex, which activated retron effectors and led to abortive infection.

References

Original article

  1. Millman, A. et al. Bacterial retrons function in anti-phage defense. Cell https://doi.org/10.1016/j.cell.2020.09.065 (2020)

    Article  PubMed  Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to Grant Otto.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Otto, G. A function for retrons. Nat Rev Microbiol 19, 3 (2021). https://doi.org/10.1038/s41579-020-00488-2

Download citation

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing