Project description:RNA base editing represents a promising alternative for genome editing. Recent approaches harness the endogenous RNA editing enzyme ADAR to circumvent problems related to the ectopic expression of an editing enzyme, but they suffer from sequence restriction, lack of efficiency, and bystander editing. Here, we present in‐silico optimized CLUSTER guide RNAs, which bind their target mRNAs in a multivalent fashion and thereby enable editing with unprecedented precision as shown by next generation sequencing. CLUSTER guide RNAs can be genetically encoded and manufactured into viruses to work in various cell lines. They achieve on‐target editing on endogenous transcripts like GUSB and NUP43 with yields up to 45% without bystander editing and have been shown to recruit endogenous ADAR in vivo. The CLUSTER approach tremendously enlarges the sequence space available for guide RNA design and opens new avenues for drug development in the field of RNA base editing.
Project description:The purpose of the this study is to determine the prevalence of germline cancer susceptibility gene mutation among Chinese population, and to find best ways to screen patients with colorectal cancer in China. To accomplish this objective, the investigators will establish a large sample database of hereditary colorectal cancer related information using multigene panel testing based on Next-Generation Sequencing.
Project description:Next Generation Sequencing in cancer: a feasibility study in France to assess sample circuit and to perform analyzes within a limited time.
Project description:While the next generation sequencing technology is accelerating the discovery of sites in RNA editing, the strategies to accurately identify the editome, the mechanism by which its profile is maintained and its functional significance remain controversial. Here, 90bp × 2, paired-end, strand-specific, polyA-postive RNA-Seq were performed in 3 rhesus monkey tissues, and 90bp × 2, paired-end, whole exome sequencing was performed in blood cells. Combining genome-wide identification and other quality control in multiple tissues from the same individual, we identified a list of editing sites in coding regions from the rhesus macaque, one of our closest evolutionary relatives. Low-scale verification validated all of these sites and the corresponding levels of editing. The editome in macaque coding region suggests RNA editing as a type of controlled, conserved regulation shaped by purifying selection. This submission represents RNA-Seq: cerebellum, lung, kidney and heart component of study.
Project description:The CRISPR/Cas genome editing approach in non-model organisms poses challenges that remain to be resolved.Here, we demonstrated a generalized roadmap for a de-novo genome-annotation approach applied to the non-model organism Macrobrachium rosenbergii. We also addressed typical genome editing challenges arising from genetic variations, such as a high frequency of single nucleotide polymorphisms, differences in sex chromosomes, and repetitive sequences that can lead to off-target events. For genome editing of M. rosenbergii, our laboratory recently adapted the CRISPR/Cas genome-editing approach to embryos and embryonic primary cell culture. In this continuation study, an annotation pipeline was trained to predict gene models by leveraging available genomic, transcriptomic, and proteomic data, enabling accurate gene prediction and guide design for knock-outs. Next-generation sequencing analysis demonstrated a high frequency of genetic variations in genes on both autosomal and sex chromosomes, which have been shown to affect the accuracy of editing analyses. To enable future applications based on the CRISPR/Cas tool in non-model organisms, we also verified the reliability of editing efficiency and tracked off-target frequencies. Despite the lack of comprehensive information on non-model organisms, this study provides an example of the feasibility of selecting and editing specific genes with a high degree of certainty.
Project description:To explore the correlation between gene mutations of metastatic colorectal cancer and TCM syndrome types based on Second-generation sequencing technology.
Project description:We present MultiEditR, the first algorithm specifically designed to detect and quantify RNA editing from Sanger sequencing (z.umn.edu/multieditr). Although RNA editing is routinely evaluated by measuring the heights of peaks from in Sanger sequencing traces, the accuracy and the precision of this approach has yet to be evaluated against gold-standards next-generation sequencing methods. Through a comprehensive comparison to RNA-seq and amplicon based deep sequencing, we show that MultiEditR is accurate, precise, and reliable for detecting endogenous and programmable RNA editing.
Project description:Prime editing is a powerful means of introducing precise changes to specific locations in mammalian genomes. However, the widely varying efficiency of prime editing across target sites of interest has limited its adoption in the context of both basic research and clinical settings. Here, we set out to exhaustively characterize the impact of the cis-chromatin environment on prime editing efficiency. Utilizing a newly developed and highly sensitive method for mapping the genomic locations of a randomly integrated “sensor”, we identify specific epigenetic features that strongly correlate with the highly variable efficiency of prime editing across different genomic locations. Next, to assess the interaction of trans-acting factors with the cis-chromatin environment, we develop and apply a pooled genetic screening approach with which the impact of knocking down various DNA repair factors on prime editing efficiency can be stratified by cis-chromatin context. Finally, we demonstrate that we can dramatically modulate the efficiency of prime editing through epigenome editing, i.e. enhancing (or restricting) local chromatin accessibility in order to increase (or decrease) the efficiency of prime editing at a target site. Looking forward, we envision that the insights and tools described here will broaden the range of both basic research and therapeutic contexts in which prime editing is useful.
Project description:Prime editing is a powerful means of introducing precise changes to specific locations in mammalian genomes. However, the widely varying efficiency of prime editing across target sites of interest has limited its adoption in the context of both basic research and clinical settings. Here, we set out to exhaustively characterize the impact of the cis-chromatin environment on prime editing efficiency. Utilizing a newly developed and highly sensitive method for mapping the genomic locations of a randomly integrated “sensor”, we identify specific epigenetic features that strongly correlate with the highly variable efficiency of prime editing across different genomic locations. Next, to assess the interaction of trans-acting factors with the cis-chromatin environment, we develop and apply a pooled genetic screening approach with which the impact of knocking down various DNA repair factors on prime editing efficiency can be stratified by cis-chromatin context. Finally, we demonstrate that we can dramatically modulate the efficiency of prime editing through epigenome editing, i.e. enhancing (or restricting) local chromatin accessibility in order to increase (or decrease) the efficiency of prime editing at a target site. Looking forward, we envision that the insights and tools described here will broaden the range of both basic research and therapeutic contexts in which prime editing is useful.
Project description:Prime editing is a powerful means of introducing precise changes to specific locations in mammalian genomes. However, the widely varying efficiency of prime editing across target sites of interest has limited its adoption in the context of both basic research and clinical settings. Here, we set out to exhaustively characterize the impact of the cis-chromatin environment on prime editing efficiency. Utilizing a newly developed and highly sensitive method for mapping the genomic locations of a randomly integrated “sensor”, we identify specific epigenetic features that strongly correlate with the highly variable efficiency of prime editing across different genomic locations. Next, to assess the interaction of trans-acting factors with the cis-chromatin environment, we develop and apply a pooled genetic screening approach with which the impact of knocking down various DNA repair factors on prime editing efficiency can be stratified by cis-chromatin context. Finally, we demonstrate that we can dramatically modulate the efficiency of prime editing through epigenome editing, i.e. enhancing (or restricting) local chromatin accessibility in order to increase (or decrease) the efficiency of prime editing at a target site. Looking forward, we envision that the insights and tools described here will broaden the range of both basic research and therapeutic contexts in which prime editing is useful.