Project description:TTN CRISPR activation rescued TTNtv-related functional deficits despite increasing truncated TTN levels, which provides evidence to support haploinsufficiency as a relevant genetic mechanism underlying heterozygous TTNtvs (TTN truncation variants). CRISPR activation could be developed as a therapeutic to treat a large proportion of TTNtvs.
Project description:USP7, which encodes a deubiquitylating enzyme, is among the most frequently mutated genes in pediatric T-ALL, with somatic heterozygous loss-of-function mutations (haploinsufficiency) predominantly affecting the subgroup that has aberrant TAL1 oncogene activation. Network analysis of >200 T-ALL transcriptomes linked USP7 haploinsufficiency with decreased activities of E-proteins. E-proteins are also negatively regulated by TAL1, leading to concerted down-regulation of E-protein target genes involved in T-cell development. In T-ALL cell lines, we show the physical interaction of USP7 with E-proteins and TAL1 by mass spectrometry and ChIP-seq. Haploinsufficient but not complete CRISPR knock-out of USP7 shown accelerated cell growth and validated transcriptional down-regulation of E-protein targets. Our study unveiled the synergistic effect of USP7 haploinsufficiency with aberrant TAL1 activation on T-ALL, implicating USP7 as a haploinsufficient tumor suppressor in T-ALL.
Project description:Haploinsufficiency, having only one functional copy of a gene, leads to a wide-range of human diseases. Using obesity as a disease model, we tested whether haploinsufficiency can be rescued by CRISPR-mediated activation (CRISPRa) of the normal allele. Haploinsufficiency of either SIM1 or MC4R, results in severe obesity in humans and mice. In transgenic mice, CRISPRa targeting of the Sim1 promoter or its ~270kb distant hypothalamic enhancer, rescued the obesity phenotype in Sim1 heterozygous mice. Interestingly, despite using a ubiquitous promoter for CRISPRa, Sim1 was upregulated only in tissues where the promoter or enhancer are active, suggesting that cis-regulatory elements can determine CRISPRa tissue-specificity. To evaluate the potential therapeutic use of CRISPRa, we injected CRISPRa-rAAV into the hypothalamus, leading to reversal of the obesity phenotype in Sim1 and Mc4r heterozygous mice. Our results show that CRISPRa can be developed as a gene regulation therapy (GRT) to treat altered gene dosage diseases.
Project description:To search for factors regulating neuronal differentiation, we performed a genome-wide loss-of-function CRISPR/Cas9 screen in haploid human ESCs. The regulators were identified by the quantification of depletion of their mutant clones within a pooled loss-of-function library upon neuronal differentiation.
Project description:To search for host factors regulating Zika virus infection, we performed a genome-wide loss-of-function CRISPR/Cas9 screen in haploid human ESCs. The regulators were identified by the quantification of enrichment of their mutant clones within a pooled loss-of-function library upon Zika virus infection.
Project description:To search for factors regulating paternally imprinted genes (PEGs), we performed a genome-wide loss-of-function CRISPR/Cas9 screen in haploid parthenogenetic ESCs. This by staining a pooled CRISPR library with a PEG10 antibody and next FACS-sorted for cells that presented de-novo PEG10 expression.
Project description:A pool of 3633 tagged heterozygous transposon disruption mutants underwent haploinsufficiency profiling in the presence of different synthetic compounds to identify their cellular targets
Project description:Genetic TNFAIP3 (A20) inactivation is a classical somatic lymphoma lesion and the genomic trait in haploinsufficiency of A20 (HA20). In a cohort of 33 HA20 patients, we show that heterozygous TNFAIP3 loss skews immune repertoires towards lymphocytes with classical self-reactive antigen receptors typically found in B and T cell lymphomas.