April 28, 2022
Single-cell expression analysis provides insights about gene expression and cell heterogeneity at the single-cell level. It enables the elucidation of intracellular gene regulatory networks and intracellular pathways that would otherwise be masked in bulk analysis (Massaia et al., 2018). The DriverMap™ Targeted Gene Expression Profiling (TXP) assay combines highly multiplexed RT-PCR amplification with the depth and precision of Next-Generation Sequencing (NGS) to quantitatively measure gene expression of up to 19,000 target genes in a single assay–even down to the single-cell level. Read More April 28, 2022
Adaptive immunity relies on B and T cells that recognize foreign antigens via hypervariable B cell and T cell receptors (BCRs and TCRs). Diversity among B cell and T cell receptors is primarily produced by V(D)J recombination, which involves the shuffling and joining of the variable (V), diversity (D), joining (J), and constant region (C) gene segments. This results in a diverse repertoire called the adaptive immune repertoire (AIR) that comprises multiple individual clonotypes (sequence) for particular receptor chains.
Read More July 06, 2020
Introducing Inducible Cas9 Expression in a Single Lentiviral Vector to make cells capable of high Cas9 expression for a limited time during which CRISPR-mediated targeted rearrangements can occur, and then shut off Cas9 expression for downstream assays with the modified cells.
Read More November 13, 2019
Perturb-Seq or CROP-Seq screens make use of single-cell RNA-Sequencing in conjunction with a pooled CRISPR library to identify transcriptional changes and, by implication, activation or deactivation of cellular pathways related to phenotypic changes produced by specific sgRNA-mediated gene knockouts. Read More April 22, 2019
Researchers at MD Anderson Cancer Center recently used a Cellecta CloneTracker Barcode Library to label patient-derived xenograft (PDX) cells and establish a stable population of aggressive tumorigenic cells with a specific set of barcodes. With this population of barcoded tumorigenic clones, the investigators...
Read More March 28, 2019
A recent article demonstrates the unique suitability of the DriverMap Expression Profiling Assay for blood biomarker analysis. In Scientific Reports, Tarca, et al. reported that DriverMap Targeted RNA sequencing identified more potential biomarkers associated with spontaneous labor than either standard Illumina...
Read More October 04, 2017
Earlier this year, 3 separate studies (Adamson, et al., Datlinger, et al., and Dixit, et al.) demonstrated an approach to combine pooled CRISPR genetic screening with RNA expression profiling at the single-cell level. Integrating these two approaches enables knockout-specific expression data to be generated for...
Read More September 05, 2017
Cellecta now offers the mouse Thy1.1 gene (Thymus Cell Antigen 1.1, CD90.1) as a marker in custom CRISPR, RNAi, and cDNA constructsThy1 genes express small, almost peptide-like T-cell glycooprotein expressed by thymocytes, hematopoietic stem cells, some fibroblast and muscle cells in most mammals. These...
Read More July 03, 2017
Essentially half of human DNA consists of repeated transposable elements or "mobile" DNA. One type of long interspersed element—LINE-1—is one of the most prevalent variants and accounts for approximately 17% of the human genome. The LINE-1 sequence is a protein-coding transposable element that copies itself through...
Read More June 01, 2017
In addition to the pooled CRISPR libraries we offer, there are a few other libraries that researchers can choose to use for gene knockout screens, such as the Broad Institute’s GeCKO and Brunello libraries available through Addgene. To conserve the limited stock of these libraries, many labs only distribute a...
Read More May 27, 2016
Using a Cellecta-made shRNA library, groups from the European Institute of Oncology and MD Anderson Cancer Center published the first in vivo pooled RNAi screen in patient-derived tumor xenograft PDX mouse models. The study published in June Cancer Discovery screened 236 epigenetic genes targeted with a pooled shRNA...
Read More April 07, 2016
Last year, Cellecta received a Phase 1 NIH SBIR grant to develop validated single guide RNA (sgRNA). The initial study was designed to investigate an approach to optimize CRISPR sgRNA to improve the efficiency of CRISPR knockout.The 5'-end of the CRISPR sgRNA contains 20 nucleotides specific to the gene targeted...
Read More July 22, 2015
Cellecta received a Phase I NIH SBIR Grant to develop CRISPR guide RNAs (gRNAs or sgRNAs) for human and mouse genes and then use these to build a knockout library targeting 6,500 key disease-related genes in major signal transduction pathways.Targeting a gene for knockout using CRISPR requires a short strand of...
Read More June 06, 2015
Researchers at Novartis recently published a study using a lentiviral based library containing many millions of unique sequences (barcodes) to label and track erlotinib-resistant non-small lung cancer cells. The approach provided a way to differentiate whether these resistant cells were already present in...
Read More April 29, 2015
Use of antibiotic resistance markers with CRISPR is an effective tool for cells that proliferate. However, for primary cells and non-dividing cells, all-in-one sgRNA-Cas9 lentiviral vector that contains a fluorescence marker (GFP-CRISPR) could be a better option.Our standard, Single-Vector CRISPR-Cas9 System...
Read More March 30, 2015
Chronic Myeloid Leukemia (CML) is characterized by increased and unregulated growth of myeloid cells in the bone marrow and accumulation of these cells in the blood. Most CML is caused by a chromosomal abnormality that results in a fusion between Abl tyrosine kinase and BCR gene on chromosome 2, which results in a constitutively active tyrosine kinase. Most CMLs are treated with tyrosine kinase inhibitors...
Read More March 12, 2015
The previous blog post " Two-Vector CRISPR System Is Better Approach for Knockout Screens" discussed the advantages of expressing the Cas9 nuclease on a vector separate from the one used for the guide RNAs (sgRNA)—a two-vector CRISPR system—when using the system for complex pooled loss-of-function screens. In...
Read More November 26, 2014
Since our introduction of the All-in-One CRISPR-Cas9 lentiviral system in the Spring, we have done a bit more work and moved forward with a two-vector system for our pooled libraries of sgRNA expression constructs. If the All-in-One CRISPR-Cas9 vector works well—which it does—why, you might wonder, would we...
Read More October 16, 2014
Most experiments that rely on lentiviral technology to deliver genetic elements benefit greatly by starting with pure high-titer virus. With some easy-to-transduce cell systems grown in routine medium, such as DMEM, it may be possible to squeak by with a dilute viral supernatant containing proteins and factors from the packaging cell culture. However, protocols involving cells that require different media...
Read More May 28, 2014
Cellecta recently developed a one-plasmid CRISPR lentiviral vector that expresses both the sgRNA and Cas9 protein. CRISPR enables convenient of a target gene at the genomic level, as opposed to shRNA which knocks down the level of the RNA transcript for the target gene.Due to the differences between the shRNA...
Read More March 25, 2014
Recently, one of our customers compared our lentiviral packaging mix with packaging mixes from two competitors. The same lentiviral vector that expresses firefly luciferase was used in all three packaging protocols. Each lentivector was packaged according to the manufacturer's instructions in 293T cells....
Read More March 12, 2014
Dr. Gregory Hoffman's group from Novartis recently used a custom library from Cellecta that identified BRM/SMARCA2 as a critical target in BRG1-deficient cancers (PMID: 24520176). The shRNA library consisted of 6500 shRNAs (380 genes with 17 shRNAs per gene) involved in epigenetic regulation. These genes represented...
Read More February 26, 2014
The ability to identify and quantify the size of clonal cell populations produced by each cell in a founder population offers researchers a powerful tool for understanding how groups cells grow and proliferate in all sorts of conditions. This sort of clonal cell tracking enables cell biologists,...
Read More January 17, 2014
Researchers at the German Cancer Research Center (DKFZ) and the MD Anderson Cancer Center used Cellecta's shRNA DECIPHER Libraries for an in vivo genetic screen that identified SALL1 as a breast cancer tumor suppressor that plays a role in E-cadherin regulation (Article)E-cadherin (CDH1) has been shown to have a...
Read More June 10, 2013
Researchers at the German Cancer Research Center (DKFZ) used Cellecta's shRNA DECIPHER libraries to identify genes that sensitize pancreatic cells to gemcitabine.Pancreatic cancer has only a 6% 5-year survival rate. Gemcitabine is the standard treatment in conjunction with surgery to remove cancerous...
Read More February 11, 2013
At Cellecta, we have relied primarily on lentiviral vectors to develop our RNAi genetic screening technology. The broad tropism of lentivirus-based plasmids packaged into VSV-g pseudotyped viral particles provides a very convenient vector system to introduce and stably express shRNA expression...
Read More January 05, 2013
2013 seems to have started at a full sprint. It feels as though the annual meeting of the American Society of Cell Biology in San Francisco just finished. We exhibited and presented a tutorial there entitled, Find Functionally Important Driver Genes with RNAi Genetic ScreeningUsing Pooled shRNA Libraries on December...
Read More October 23, 2012
It's been a while since the last post to this blog. It is not that nothing has been going on, in fact, quite the opposite. It has been quite busy the past several months and, unfortunately, blog postings have suffered. However, I thought I would get things started again with short post about our recent SBIR...
Read More March 20, 2012
Our group recently ran across an article describing an independent RNAi screen with a non-Cellecta pooled shRNA expression library that piqued our interest. In the October 2011 online Genome Biology Journal, Sims, et al. comprehensively described how to run a rigorous genome-wide pooled RNA interference screen...
Read More February 03, 2012
A couple of months ago at the CHI Discovery on Target Conference, Hakim Djaballah, Director of the HTS Core Facility at the Memorial Sloan Kettering Cancer Center, gave a unique and insightful presentation highlighting the challenges RNAi screening to identify lethal loss of function interaction in oncogenic...
Read More October 14, 2011
We recently received a phase II of our SBIR grant Exploiting Synthetic Lethality of Hematopoietic Lineage Cells to Develop Novel Targets from the NIH. Rather than trying to identify potential drug targets in oncogenic hematopoietic cells, much of the effort for this project focuses on trying to develop a...
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