Knockout of microRNAs Using the CRISPR-Cas9 System with Paired Synthetic crRNAs
Poster Apr 24, 2018
Eldon T. Chou, John A. Schiel, Elena Maksimova, Travis Hardcastle, Emily A. Anderson, Annaleen Vermeulen, Anja van Brabant Smith
The CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 (CRISPR-associated 9) system derived from Streptococcus pyogenes uses a Cas9 nuclease directed by a guide RNA (gRNA) to create a DNA double-strand break (DSB) at the target site. The gRNAs can be dual synthetic molecules, like the native bacterial system containing a CRISPR RNA (crRNA) and a trans-activating CRISPR RNA (tracrRNA) (Figure 1), or a single synthetic guide RNA (sgRNA). The DSB is most often repaired by either nonhomologous end joining (NHEJ) or homology directed repair (HDR) through endogenous mechanisms within mammalian cells. NHEJ can result in insertions or deletions (indels) that produce functional gene knockouts through nonsense mutations or introduction of a stop codon. When using CRISPR-Cas9 components targeting coding genes, there are typically multiple protospacer adjacent motif (PAM) sequences (NGG for S. pyogenes) to choose from along the gene to design a gRNA. For most CRISPR Cas9 genome engineering experiments, one targeting gRNA is sufficient to generate the desired functional gene knockout. However, for some applications, it may be advantageous to use two gRNAs to generate a larger deletion and ensure gene knockout or to remove an exon, long non-coding RNA (lncRNA), or transcriptional regulatory element.
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
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.
Studies have shown that IFI16 acts as an antiviral restriction factor against a number of DNA viruses, by inhibiting viral replication or transcription through epigenetic modifications. However, till date, no specific epigenetic function of IFI16 has been identified. Here, we have discovered that IFI16 recruits two histone methyltransferases on the KSHV episome leading to altered Histone H3K9 methylation, thus regulating its lifecycle.READ MORE