Thermus and Pyrococcus Argonautes have been characterised as novel defence systems, revealing their unique property to use DNA guides for DNA interference.
Currently, mesophilic Argonaute variants are being analysed. CRISPR-Cpf1, of the pathogenic bacterium Francisella, has been characterised, establishing its potential as a powerful genome-editing tool. A recent discovery concerns links between the Cas9 of pathogenic bacteria and their virulence.
The finding that guide-free Cas9 may act as a DNA-degrading virulence factor in human cells, reveals a novel strategy of pathogenic bacteria. Moreover, it implies that guide-saturation is crucial for safe application of Cas9 in gene therapy. Molecular details of this unexpected link (guided nucleases) will be studied, in more detail, in the coming years.