CRISPR-Cas9 Genome Editing Utilizing Chemically Synthesized RNA
Poster May 06, 2016
Kaizhang He, Eldon Chou, Amanda Haas, Žaklina Strezoska, Melissa L. Kelley, and Anja van Brabant Smith Dharmacon, part of GE Healthcare, 2650 Crescent Drive, Lafayette, CO 80026, USA
The CRISPR-Cas9 system permits researchers to quickly edit genes for functional protein knockout in mammalian, fish and plant genomes, among others, and consequently has dramatically transformed biological research. The CRISPR-Cas9 system requires exogenous Cas9 nuclease to be delivered into the cell, which can be accomplished through transfection of an expression plasmid, mRNA or protein, or through transduction with lentiviral particles. Besides Cas9 nuclease, the natural CRISPR-Cas9 system also requires two RNA components: CRISPR RNA (crRNA) comprised of spacer-derived sequence and of repeat-derived sequence and tracrRNA, which hybridizes to the crRNA through repeat-derived sequences. The crRNA:tracrRNA complex recruits the Cas9 nuclease and cleaves DNA upstream of a protospacer-adjacent motif (PAM). The crRNA and tracrRNA can be linked together with a loop sequence for generation of a chimeric single guide RNA (sgRNA). In a vector-based approach, cloning and sequence verification of each sgRNA vector can be laborious and time consuming, especially if the goal is to study tens or thousands of gene targets. Likewise, in vitro transcription of the sgRNA also requires additional time and quality control to ensure consistency in length and purity of the transcribed product. In contrast, chemical synthesis can easily be employed for rapidly generating the crRNA and tracrRNA molecules separately or a synthetic sgRNA for direct delivery into cells for gene editing.
Genome-wide association studies (GWAS) have identified more than 100 genetic loci associated with type 2 diabetes. The majority of these are located in the intergenic or intragenic regions suggesting that the implicated variants may alter chromatin conformation. This, in turn, is likely to influence the expression of nearby or more remotely located genes to alter beta cell function. At present, however, detailed molecular and functional analyses are still lacking for most of these variants. We recently analysed one of these loci and mapped five causal variants in an islet-specific enhancer cluster within the STARD10 gene locus. Here, we aimed to understand how these causal variants influence b-cell function by alteration of the chromatin structure of enhancer clusterREAD MORE
The nuclear receptors pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are closely related transcription factors that regulate the expression of phase I (cytochrome P450s), phase II metabolizing enzymes and transporter genes in response to xenobiotics, including prescription drugs.READ MORE
Early life stress (ELS) is highly associated with development of psychopathology
and mood disorders in adulthood. Genetic studies have identified variation in the gene calcium voltage-gated channel subunit alpha1C (CACNA1C) to increase risk for several psychiatric disorders. This poster assessed the expression of Cacna1c following prepubertal stress.