The advent of CRISPR-Cas (Clustered regularly interspaced short palindromic repeats-CRISPR associated) makes it feasible to target/edit the genome with precision. Most of the CRSIPR-Cas systems show a trans nuclease activity upon binding their specific target, which is absent in FnCas9 (Cas9 derived from Francisella novicida). This high specificity along with an extremely high mismatch sensitivity (binding is abolished if there is more than a single base pair mismatch between guide RNA and the substrate DNA) of FnCas9 makes it possible to target and edit SNPs with precision. The proof-of-concept for which has been shown by the correction of the Sickle Cell Disease (SCD) point mutation (in patient derived iPSCs, induced pluripotent stem cells) and the detection of SCD/COVID-19 by FELUDA (FnCas9 linked uniform detection assay is a robust, rapid, and inexpensive point-of-care test).
FnCas9 based genome editing and nucleic acid detection
Debojyoti Chakraborty, Senior Scientist, CSIR-IGIB, New Delhi, India