Fecha de publicación: -- Fuente: WIPO "tomato" Tandem Interspaced Guide RNA (TIGR) systems are disclosed that offer a unique RNA-guided mechanism for genome manipulation with several distinct advantages over existing CRISPR systems. Conserved across bacteria and viruses, TIGR arrays have a dual repeat architecture that, once transcribed into precursor RNA, are processed into 36-nt tigRNAs that bind to Nop domain- containing TIGR-associated nuclease proteins, or "Tas" proteins. TigRNAs act as guide RNAs, directing the tigRNA-Tas complex to a target nucleotide sequence where tandem spacer interactions with complementary sequences on both strands of a target nucleotide sequence result in a staggered double-strand DNA cleavage. Unlike CRISPR, TIGR systems do not depend on PAM or similar sequence elements, allowing flexible target site selection. Tas proteins are also shown to cleave target sequences in human cells. The modular structure of TIGR and lack of targeting motif requirements, TIGR is a powerful tool for programmable DNA cleavage and base/prime editing systems.