The widespread IS200/IS605 transposon family encodes diverse programmable RNA-guided endonucleases

• Main Authors: Altae-Tran, Han (Author), Kannan, Soumya (Author), Demircioglu, F Esra (Author), Oshiro, Rachel (Author), Nety, Suchita P (Author), McKay, Luke J (Author), Dlakić, Mensur (Author), Inskeep, William P (Author), Makarova, Kira S (Author), Macrae, Rhiannon K (Author), Koonin, Eugene V (Author), Zhang, Feng (Author)
• Format: Article
• Language: English
• Published: American Association for the Advancement of Science (AAAS), 2022-04-25T17:24:22Z.
• Subjects: Article
• Online Access: Get fulltext

 IscB proteins are putative nucleases encoded in a distinct family of IS200/IS605 transposons and are likely ancestors of the RNA-guided endonuclease Cas9, but the functions of IscB and its interactions with any RNA remain uncharacterized. Using evolutionary analysis, RNA sequencing, and biochemical experiments, we reconstructed the evolution of CRISPR-Cas9 systems from IS200/IS605 transposons. We found that IscB uses a single noncoding RNA for RNA-guided cleavage of double-stranded DNA and can be harnessed for genome editing in human cells. We also demonstrate the RNA-guided nuclease activity of TnpB, another IS200/IS605 transposon-encoded protein and the likely ancestor of Cas12 endonucleases. This work reveals a widespread class of transposon-encoded RNA-guided nucleases, which we name OMEGA (obligate mobile element-guided activity), with strong potential for developing as biotechnologies.