Project description:tRNase ZL-utilizing efficacious gene silencing (TRUE gene silencing) is an RNA-mediated gene expression control technology that has therapeutic potential. This technology is based on the properties of tRNase ZL that it can cleave any target RNA at any desired site under the direction of an appropriate artificial small guide RNA (sgRNA) and that cytosolic tRNase ZL can modulate gene expression by cleaving mRNA under the direction of cellular 5M-bM-^@M-2-half-tRNA or microRNA as sgRNA. In order to estimate a number of potential therapeutic heptamer-type sgRNAs for hematological malignancies, we constructed an sgRNA library composed of 156 heptamer-type sgRNAs, and examined how the sgRNAs affect viability of leukemia and myeloma cells. And we found that 20 of the 156 sgRNAs can efficiently induce apoptosis in at least one of the cancer cell lines. Furthermore, we demonstrated that 4 of the 20 effective sgRNAs can reduce growth rates of HL60 cells in mouse xenograft models. DNA microarray analysis for changes in an mRNA profile by these four heptamer-type sgRNAs suggested at least one candidate target mRNA that contains a potential tRNase ZL target site for each sgRNA. Changes in gene expression in HL60 cells were measured after 18-hour incubation in the absence or presence of one of five different heptamer-type sgRNAs. *Heptamer sequences requested but not provided by submitter
Project description:To minimize the human genome-wide CRISPR/Cas9 library size, we established H-mLib which recruited a novel sgRNA design method and applied with dual plasmid based strategy. The performance of the H-mLib was benchmarked to other CRISPR libraries in a proliferation screening conducted in K562 cells. We also identified human core essential genes and cell-type specific essentials genes in K562 and Jurkat cells.
Project description:Following a CRISPR enhancer scan covering the GATA2 super-enhancer region, the top sgRNAs were selected for further inspection. MUTZ3 cells were thus treated with the selected sgRNAs and the region of interested was subjected to amplicons sequencing (amplicon-seq). To that end, we used the Illumina PCR-based custom amplicon sequencing method using the TruSeq Custom Amplicon index kit (Illumina). The same experiment was conducted in K562 cells, which do not harbor an inv(3)/t(3;3), to investigate the role of MYB in this enhancer in other leukemia settings
Project description:We have combined a machine-learning approach with other strategies to optimize the efficiency of sgRNAs for CRISPR screens and have constructed a genome-wide, sequence-verified, arrayed CRISPR library. This incorporates expression strategies to facilitate multiplexed or combinatorial screening. By conducting parallel loss-of-function screens, we compare our approach to existing sgRNA design and expression strategies.
Project description:We have combined a machine-learning approach with other strategies to optimize the efficiency of sgRNAs for CRISPR screens and have constructed a genome-wide, sequence-verified, arrayed CRISPR library. This incorporates expression strategies to facilitate multiplexed or combinatorial screening. By conducting parallel loss-of-function screens, we compare our approach to existing sgRNA design and expression strategies.
Project description:We have combined a machine-learning approach with other strategies to optimize the efficiency of sgRNAs for CRISPR screens and have constructed a genome-wide, sequence-verified, arrayed CRISPR library. This incorporates expression strategies to facilitate multiplexed or combinatorial screening. By conducting parallel loss-of-function screens, we compare our approach to existing sgRNA design and expression strategies.
Project description:We conducted a two-vector CRISPR/Cas13d proliferation screening experiment. The screening library contains 10,830 sgRNAs targeting 192 protein-coding genes and 234 lncRNAs, and the screening experiment was performed using a melanoma cell line A375. It provides a unique dataset to model Cas13d sgRNA efficiency and specificity. We designed a deep learning model, named DeepCas13, to predict the sgRNA on-target activity with high accuracy from sgRNA sequences and RNA secondary structures.
Project description:tRNase ZL-utilizing efficacious gene silencing (TRUE gene silencing) is an RNA-mediated gene expression control technology that has therapeutic potential. This technology is based on the properties of tRNase ZL that it can cleave any target RNA at any desired site under the direction of an appropriate artificial small guide RNA (sgRNA) and that cytosolic tRNase ZL can modulate gene expression by cleaving mRNA under the direction of cellular 5′-half-tRNA or microRNA as sgRNA. In order to estimate a number of potential therapeutic heptamer-type sgRNAs for hematological malignancies, we constructed an sgRNA library composed of 156 heptamer-type sgRNAs, and examined how the sgRNAs affect viability of leukemia and myeloma cells. And we found that 20 of the 156 sgRNAs can efficiently induce apoptosis in at least one of the cancer cell lines. Furthermore, we demonstrated that 4 of the 20 effective sgRNAs can reduce growth rates of HL60 cells in mouse xenograft models. DNA microarray analysis for changes in an mRNA profile by these four heptamer-type sgRNAs suggested at least one candidate target mRNA that contains a potential tRNase ZL target site for each sgRNA.
Project description:CRISPR interference (CRISPRi) genetic screens use programmable repression of gene expression to systematically explore questions in cell biology and genetics. However, wider adoption of CRISPRi screening has been constrained by the large size of single guide RNA (sgRNA) libraries and lack of consensus on the choice of CRISPRi effector proteins. Here, we address these challenges to present next-generation CRISPRi sgRNA libraries and effectors. First, we combine empiric sgRNA selection with a dual sgRNA library design to generate an ultra-compact, highly active CRISPRi sgRNA library. Next, we rigorously compare CRISPRi effectors to show that the recently published Zim3-dCas9 provides an optimal balance between strong on-target knockdown and minimal nonspecific effects on cell growth or the transcriptome. Finally, we engineer a suite of cell lines which stably express Zim3-dCas9 and demonstrate robust on-target knockdown across these cell lines. Our results and publicly available reagents establish best practices for CRISPRi genetic screening.
Project description:Five different sgRNAs targeting mCherry gene (wild-type, without a spacer, and three truncated variants) were used to investigate the off-target effects of CRISPR interference.