Feng Zhang at the Broad Institute at MIT and Harvard was part of the team that originally showed that CRISPR-Cas9 gene editing could function in human cells . His lab has lead the developent of CRISPR-Cas13 as a biological research tool and for biomedical applications. Zhang’s lab has shown that one member of the Cas13 enzyme family, Cas13a from Leptotrichia wadei, can be used to knockdown mammalian and plant cell RNA to reduce the expression of the target gene . Zhang’s lab also engineered an inactive form of Cas13a with GFP that binds RNA without cutting which can make RNA of interest trackable in live cells .
Zhang and collaborators developed a nucleic acid detection system based on Cas13a, called SHERLOCK (Specific High Sensitivity Enzymatic Reporter UnLOCKing) that can detect viruses, distinguish pathogenic bacteria, genotype human DNA and cell-free tumor DNA mutations . DNA or RNA is amplified with recombinase polymerase and converted to RNA with T7 RNA polymerase. When Cas13a recognizes its RNA target it cleaves non-target RNA nearby. SHERLOCK includes a reporter RNA that fluoresces when cleaved to show target virus sequence has been detected. Zhang collaborated with virology researcher Pardis Sabeti, also at the Broad Institute at MIT and Harvard to demonstrate the use of SHERLOCK to detect Zika virus and dengue virus, instrument-free, in patient body fluids (urine and saliva) at concentrations of 1 copy per microliter .
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- Synthetic biologySynthetic biology is a multidisciplinary area of research that seeks to create new biological parts, devices, and systems, or to redesign systems that are already found in nature to have new abilities.
- BiotechnologyBiotechnology in a broad sense includes the use of living systems and organisms, as well as their parts for the development or production of products.
- CRISPR/Cas ToolsClustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR associated (Cas) proteins perform adaptive immune functions in prokaryotic organisms defending against foreign nucleic acids such as viruses. CRISPR/Cas tools have been adapted for use in genome editing and other DNA and RNA targeting applications.
- CRISPRClustered regularly interspaced short palindromic repeats (CRISPR) is a prokaryotic adaptive immune response that provides immunity against foreign nucleic acids, such as viral DNA and bacterial plasmids, through the use of crRNAs (CRISPR RNAs) and associated Cas genes.
- CRISPR-Cas9CRISPR-Cas9 is a genome editing system. CRISPR systems provides immunity to bacteria and archaea from viruses and has been adapted for use as a genome editing tool capable of knocking out genes and rewriting genetic sequences in animal, plant and fungi. CRISPR-Cas9 is being adapted to other applications outside genome editing.
- CRISPR-Cas13A nucleic acid editing technology that targets RNA, analogous to the CRISPR-Cas9 system
- CRISPR-Cas13bNucleic acid editing technology that targets RNA and is being developed as a tool for editing pathogenic mutations in RNA transcripts.
- CRISPR-Cas12aCRISPR-Cas12a is is a genome editing tool similar to CRISPR-Cas9. CRISPR-Cas12a is a set of RNA guided DNA targeting proteins capable of producing targeted double-stranded DNA (dsDNA) breaks, targeted single-stranded DNA breaks, and indiscriminate ssDNA degradation in trans. The effector protein Cas12a is also known at Cpf1.