Cellecta offers pre-made and custom pooled shRNA libraries that have been used in a number of highly cited and published genetic screening experiments for discovery and functional characterization of novel therapeutic targets.
Cellecta offers pre-made pooled and custom lentiviral-based libraries containing heterogeneous mixtures of shRNA that allow you to assay the effects of many thousands of constructs in one experiment. Our pre-made, pooled lentiviral genome-wide shRNA libraries target nearly all protein-encoding genes for human or mouse. In addition, we can make precisely defined high quality custom pooled libraries with well designed shRNAs targeting any set of your genes of interest in just a couple of months.
By taking advantage of array-based oligonucleotide synthesis technologies, we can readily make precisely defined large custom pooled libraries expressing many thousands of shRNAs. In approximately 2 months, we can produce a completely new, high-quality custom library focusing on any target set of genes. The library vector can also be easily customized, and the same library oligonucleotides can be cloned into more than one vector backbone (e.g. with an inducible and constitutive shRNA). It is a very flexible platform that enables us to easily meet your experimental needs.
Screening readout of enrichment or depletion representation of particular shRNAs is greatly facilitated by the incorporation of easily sequenced unambiguous barcodes in each shRNA construct. Direct amplification and sequencing of hairpins is problematic, and increases variability in the data since small sequence variations of the hairpin stem significantly affect the efficiency of PCR leading to increased noise in the data readout. The incorporation of shRNA-specific barcodes addresses this problem inherent to pooled shRNA screens.
Genetic screens with shRNA libraries can be utilized to investigate most aspects of biology that can be recapitulated in a cell culture model. As opposed to expressing and assaying the functional effects of an individual shRNA molecule, the development of complex shRNA libraries allows for simultaneous screening of thousands of different shRNA molecules in a target population. In general, genetic screens represent an unbiased approach to identify genes that act in specific cellular pathways. High-throughput (HT) RNAi genetic screens have been proven to be an extremely powerful and versatile tool to explore the molecular basis of cancer development and progression, and to discover genes essential for viability in cancer cells that can subsequently be used as targets for anticancer drug development.
Genetic screens using pooled shRNA libraries require that recipient cells with desired phenotypic changes be selected from a pool of unaffected cells. Selection may be based on cell survival, appearance of specific markers, induction of reporter constructs, changes in cell morphology or behavior, etc. The design of a selection strategy is the most critical arm of any genetic screening project. Repeated rounds of selection may be necessary for either secondary validation or to reduce the number of false positives that could increase the percentage of positive hits.