Project description:Understanding the impact of splicing and nonsense variants on RNA is crucial for the resolution of variant classification as well as their suitability for precision medicine interventions. This is primarily enabled through RNA studies involving transcriptomics followed by targeted assays using RNA isolated from clinically accessible tissues (CATs) such as blood or skin of affected individuals. Insufficient disease gene expression in CATs does however pose a major barrier to RNA based investigations, which we show is relevant to 1,436 Mendelian disease genes. We term these ‘silent’ Mendelian genes (SMGs), the largest portion (36%) of which are associated with neurological disorders. We developed two approaches to induce SMG expression in human dermal fibroblasts (HDFs) to overcome this limitation, including CRISPR-activation based gene transactivation, and fibroblast-to-neuron transdifferentiation. Initial transactivation screens involving 40 SMGs stimulated our development of a highly multiplexed transactivation system culminating in the 6- to 90,000-fold induction of expression of 20/20 (100%) SMGs tested in HDFs. Transdifferentiation of HDFs directly to neurons led to expression of 193/516 (37.4%) of SMGs implicated in neurological disease. The magnitude and isoform diversity of SMG expression following either transactivation or transdifferentiation was comparable to clinically relevant tissues. We apply transdifferentiation and/or gene transactivation combined with short- and long-read RNA sequencing to investigate the impact that variants in USH2A, SCN1A, DMD and PAK3 have on RNA using HDFs derived from affected individuals. Transactivation and transdifferentiation represent rapid, scalable functional genomic solutions to investigate variants impacting SMGs in the patient cell and genomic context.
Project description:To understand the effect of LncMyod on MyoD-induced transdifferentiation of 10T1/2 fibroblast cells, we performed RNA-seq on LncMyoD-KO 10T1/2 fibroblasts with MyoD-induced transdifferentiation.
Project description:Determining the pathogenicity of human genetic variants is a critical challenge, and functional assessment is often the only option. Experimentally characterizing millions of possible missense variants in thousands of clinically important genes will likely require generalizable, scalable assays. Here we describe Variant Abundance by Massively Parallel Sequencing (VAMP-seq), which measures the effects of thousands of missense variants of a protein on intracellular abundance in a single experiment. We applied VAMP-seq to quantify the abundance of many thousands of single amino acid variants of two proteins, PTEN and TPMT, in which functional variants are clinically actionable.
Project description:Assessment of technical error in a dual-channel, two timepoint experiment using White lab Drosophila melanogaster microarrays Keywords: repeat sample
Project description:Most transcription factors possess at least one long intrinsically disordered transactivation domain that binds to a variety of co-activators and co-repressors and plays a key role in modulating the transcriptional activity. Despite the crucial importance of these mechanisms, the structural and functional basis of transactivation domain in yet poorly understood. Here, we focused on ATF4/CREB-2, an essential transcription factor for cellular stress adaptation. We found that the N-terminal region of the transactivation domain is involved in transient long-range interactions with the basic-leucine zipper domain. In vitro phosphorylation assays with the protein kinase CK2 show that the presence of the basic-leucine zipper domain is required for optimal phosphorylation of the transactivation domain. This study uncovers the intricate coupling existing between the transactivation and basic-leucine zipper domains of ATF4 and highlights its potential functional relevance.