Project description:Genetic manipulation of organisms using CRISPR/Cas9 technology generally produces small insertions/deletions (indels) that can be difficult to detect. Here, we describe a technique to easily and rapidly identify such indels. Sequence-identified mutations that alter a restriction enzyme recognition site can be readily distinguished from wild-type alleles using a cleaved amplified polymorphic sequence (CAPS) technique. If a restriction site is created or altered by the mutation such that only one allele contains the restriction site, a polymerase chain reaction (PCR) followed by a restriction digest can be used to distinguish the two alleles. However, in the case of most CRISPR-induced alleles, no such restriction sites are present in the target sequences. In this case, a derived CAPS (dCAPS) approach can be used in which mismatches are purposefully introduced in the oligonucleotide primers to create a restriction site in one, but not both, of the amplified templates. Web-based tools exist to aid dCAPS primer design, but when supplied sequences that include indels, the current tools often fail to suggest appropriate primers. Here, we report the development of a Python-based, species-agnostic web tool, called indCAPS, suitable for the design of PCR primers used in dCAPS assays that is compatible with indels. This tool should have wide utility for screening editing events following CRISPR/Cas9 mutagenesis as well as for identifying specific editing events in a pool of CRISPR-mediated mutagenesis events. This tool was field-tested in a CRISPR mutagenesis experiment targeting a cytokinin receptor (AHK3) in Arabidopsis thaliana. The tool suggested primers that successfully distinguished between wild-type and edited alleles of a target locus and facilitated the isolation of two novel ahk3 null alleles. Users can access indCAPS and design PCR primers to employ dCAPS to identify CRISPR/Cas9 alleles at http://indcaps.kieber.cloudapps.unc.edu/.
Project description:Polymerase chain reaction (PCR) is widely applied in clinical and environmental microbiology. Primer design is key to the development of successful assays and is often performed manually by using multiple nucleic acid alignments. Few public software tools exist that allow comprehensive design of degenerate primers for large groups of related targets based on complex multiple sequence alignments. Here we present a method for designing such primers based on tree building followed by application of a set covering algorithm, and demonstrate its utility in compiling Multiplex PCR primer panels for detection and differentiation of viral pathogens.
Project description:Purpose: The goals of this study are to introduce a new genome editing tool, which has the higher editing scope than the original genome editing tools. Methods: First, we transfected PE2 (the original prime editing tool, prime editor2), PE3 (the original prime editing tool, prime editor3) and HOPE (the new tool we developed in this study) vectors into human cells, respectively. Then, we harvested the genomic DNA form the transfected cells and amplified the specified amplicons. Finally, we used targeted amplicon sequencing approach to compare the editing efficiency and presion of the new tool with the original reported tools. Results: Our new genome editing tool improves the editing efficiency of prime editing without increasing the risk of undesired indels formation. Conclusions: We deleveped a new genome editing tool to increase the likelihood of successful gene engineering.
Project description:BackgroundDifferent algorithms have been proposed to solve various versions of degenerate primer design problem. For one of the most general cases, multiple degenerate primer design problem, very few algorithms exist, none of them satisfying the criterion of designing low number of primers that cover high number of sequences. Besides, the present algorithms require high computation capacity and running time.ResultsPAMPS, the method presented in this work, usually results in a 30% reduction in the number of degenerate primers required to cover all sequences, compared to the previous algorithms. In addition, PAMPS runs up to 3500 times faster.ConclusionDue to small running time, using PAMPS allows designing degenerate primers for huge numbers of sequences. In addition, it results in fewer primers which reduces the synthesis costs and improves the amplification sensitivity.
Project description:CRISPR/Cas systems have gained prominence as powerful tools for genome engineering. Recent investigations into the crucial role of transposable elements (TEs) have stimulated research interest in manipulating TEs to elucidate their functions. Nevertheless, designing single guide RNAs (sgRNAs) that are both specific and efficient for TE manipulation presents a formidable challenge, considering the repetitive nature and high copy numbers of TEs. Although various sgRNA design tools have been developed for gene editing, an optimized sgRNA designer explicitly for TE manipulation has yet to be established. To bridge this gap, we presented CRISPR-TE, a web-based application featuring an accessible graphical user interface, available at https://www.crisprte.cn. CRISPR-TE could identify all potential sgRNAs for TEs and offers a comprehensive solution for efficient TE targeting at both the single duplicate and subfamily levels. We also demonstrated that young TEs can be targeted with higher coverage at the subfamily level. Finally, we validated the overexpression of SVAD, a human-specific TE, using dCas9-VP64 activator incorporated with three sgRNAs designed by our tool. Collectively, our findings suggest that CRISPR-TE may serve as a versatile framework for designing sgRNAs aimed at TE targeting.
Project description:SummaryGenerate Indexes for Libraries (GIL) is a software tool for generating primers to be used in the production of multiplexed sequencing libraries. GIL can be customized in numerous ways to meet user specifications, including length, sequencing modality, color balancing, and compatibility with existing primers, and produces ordering and demultiplexing-ready outputs.Availability and implementationGIL is written in Python and is freely available on GitHub under the MIT license: https://github.com/de-Boer-Lab/GIL and can be accessed as a web-application implemented in Streamlit at https://dbl-gil.streamlitapp.com.
Project description:CRISPR-Cas9 has been widely used to functionally interrogate multiple aspects of cellular physiology and pathophysiology from single gene studies to genome-wide screens. Proper design of highly efficient guide RNAs directing the CRISPR genome editing process is critical for success in these types of experiments. Here, we present a pipeline for designing highly efficient loss-of-function guide RNA (gRNA) libraries with improved rates of knock-out efficiency compared to previous guide RNA library designs. We provide pre-computed and triaged gRNAs from our pipeline for all human and mouse transcripts through a fully searchable online portal as a resource to the community.
Project description:Ligands of the TGF-β/BMP superfamily are crucially involved in the regulation of growth, patterning and organogenesis and can act as long-range morphogens. Essential for understanding TGF-β/BMP signaling dynamics and regulation are tools that allow monitoring and manipulating pathway components at physiological expression levels and endogenous spatiotemporal patterns. We used genome engineering to generate a comprehensive library of endogenously epitope- or fluorescent-tagged versions of receptors, co-receptors, transcription factors and key feedback regulators of the Drosophila BMP and Activin signaling pathways. We demonstrate that the generated alleles are biologically active and can be used for assessing tissue and subcellular distribution of the corresponding proteins. Furthermore, we show that the genomic platforms can be used for in locus structure-function and cis-regulatory analyses. Finally, we present a complementary set of protein binder-based tools, which allow visualization as well as manipulation of the stability and subcellular localization of epitope-tagged proteins, providing new tools for the analysis of BMP signaling and beyond.