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Biomedical subjects

Ryan N Jackson

Publications and source records attributed to Ryan N Jackson.

3 recordsLinked to original sources

Targeting cancer-specific mutations with RNA-triggered chromatin shredding.

Genetic mutations that drive cancer often occur in tumour-suppressor proteins such as the p53 transcription factor, which is altered in 40-50% of cases1,2. However, current therapies often fail to target these mutations because the mutant proteins typically lack defined drug-binding pockets and restoring their endogenous function has proven challenging. Here we program Cas12a2, an RNA-guided CRISPR nuclease with trans-nucleolytic cleavage activity3,4, to kill cancer cells selectively by targeting cancer-specific transcripts. This approach limited cell growth by inducing trans shredding of chromatin and triggering DNA-damage responses and cell death. In contrast to existing methods, RNA-guided Cas12a2 senses cellular RNA signatures, enabling precise targeting of undruggable mutations. Transcript-activated chromatin shredding provides an innovative approach to precision disease treatments for undruggable targets.

Animals

Determining the biochemical function of type IV CRISPR ribonucleoprotein complexes and accessory proteins.

Type IV CRISPR systems are phylogenetically diverse and poorly understood. However, recently, major strides have been made toward understanding type IV-A systems. In type IV-A systems, a multi-subunit ribonucleoprotein complex, called the Csf complex, uses a CRISPR-derived guide to bind double-stranded DNA, forming an R-loop to which a helicase called CRISPR-associated DinG (CasDinG) is recruited. It is proposed that the ATP-dependent helicase activity of CasDinG then unwinds duplex DNA near the targeting site, impairing RNA transcription, and gene expression. Here we describe methods used to investigate the type IV-A system from Pseudomonas aeruginosa strain 83 including a plasmid clearance assay, expression and purification of type IV ribonucleoprotein complexes and proteins, nucleic acid binding assays, and CasDinG helicase assays. These methods provide a foundation for future work aimed at understanding these enigmatic systems.

Ribonucleoproteins