Method and system of nucleic acid sequence detection

Samenvatting

A type lll-B system from Haliangium ochraceum contains two caspase-like proteases, SAVED-CHAT and PCaspase (prokaryotic caspase). Cyclic tri-adenosine monophosphate (AMP)-induced oligomerization of SAVED-CHAT activates proteolytic activity of the CHAT domains, which specifically cleave and activate PCaspase. Subsequently, activated PCaspase cleaves a multitude of proteins, which results in a strong interference phenotype in vivo in Escherichia coli. This provides for a CRISPR-Cas-based method of detecting a target RNA, whereby detection signalling is triggered via a cascade of caspase-associated proteolytic activities. Polynucleotides, plasmids, vectors and nucleoprotein complexes comprising nucleic acids encoding the components of the system are provided.