E-MTAB-10445
CRISPR-Cas9 screening of lncRNAs and protein coding genes involved in the transdifferentiation from human pre-B cells into macrophages
BLaER1 cells are human leukemia pre-B cells able to transdifferentiate into functional and non-tumorigenic macrophages. With the goal of uncovering the genes involved in the transdifferentiation process, we have designed a DECKO (Double Excision CRISPR Knockout) library to knockout lncRNAs and protein coding genes (pc-genes) overexpressed along the seven days the process lasts. We have seen that targeting pc-genes with two gRNAs synergistically enhances the efficiency of knock out, by inducing deletions and/or frameshifts that promote the expression of non-functional proteins. Thus, using the CRISPETa tool, we designed paired guide RNAs targeting either the region surrounding the Transcription Start Site of the 166 lncRNAs or the coding exons of the 874 pc candidate genes. Cas9-expressing BLaER1 cells were infected at low-multiplicity of infection with the combined library and induced transdifferentiation. Delayed and differentiated subpopulations of cells were isolated by Fluorescence-Activated Cell Sorting at 3 days and 6 days after induction, and pgRNAs were sequenced in an Illumina HiSeq2500 instrument. The sequencing reads were mapped and quantified to uncover the enriched pgRNAs found in each subpopulation. Among all genes targeted in the library, we identified twenty pc-genes and six lncRNAs as strong candidates to be involved in the process, as the pgRNAs targeting their loci were enriched in the delayed population compared to the differentiated one, either at 3 days or at 6 days after transdifferentiation induction. From these, we selected two pc-genes and two lncRNAs for deeper characterization.
BLaER1 cells are human leukemia pre-B cells able to transdifferentiate into functional and non-tumorigenic macrophages. With the goal of uncovering the genes involved in the transdifferentiation process, we have designed a DECKO (Double Excision CRISPR Knockout) library to knockout lncRNAs and protein coding genes (pc-genes) overexpressed along the seven days the process lasts. We have seen that targeting pc-genes with two gRNAs synergistically enhances the efficiency of knock out, by inducing deletions and/or frameshifts that promote the expression of non-functional proteins. Thus, using the CRISPETa tool, we designed paired guide RNAs targeting either the region surrounding the Transcription Start Site of the 166 lncRNAs or the coding exons of the 874 pc candidate genes. Cas9-expressing BLaER1 cells were infected at low-multiplicity of infection with the combined library and induced transdifferentiation. Delayed and differentiated subpopulations of cells were isolated by Fluorescence-Activated Cell Sorting at 3 days and 6 days after induction, and pgRNAs were sequenced in an Illumina HiSeq2500 instrument. The sequencing reads were mapped and quantified to uncover the enriched pgRNAs found in each subpopulation. Among all genes targeted in the library, we identified twenty pc-genes and six lncRNAs as strong candidates to be involved in the process, as the pgRNAs targeting their loci were enriched in the delayed population compared to the differentiated one, either at 3 days or at 6 days after transdifferentiation induction. From these, we selected two pc-genes and two lncRNAs for deeper characterization.