Biology subjects

Wang, R. Y.

Publications and source records attributed to Wang, R. Y..

5 recordsLinked to original sources

bioRxiv2022

CRISPR-Mediated Generation and Characterization of a Gaa Homozygous c.1935C>A (p.D645E) Pompe Disease Knock-in Mouse Model Recapitulates Human Infantile Onset-Pompe Disease

Pompe disease (PD) is an autosomal recessive disorder caused by deficient lysosomal acid -glucosidase (GAA), leading to reduced degradation and subsequent accumulation of intra-lysosomal glycogen in tissues, especially skeletal and oftentimes cardiac muscle. The c.1935C>A (p.Asp645Glu) variant is the most frequent GAA pathogenic mutation in people of Taiwanese and Southern Chinese ethnicity, causing infantile-onset PD (IOPD), which presents neonatally with severe hypertrophic cardiomyopathy, profound muscle hypotonia, and respiratory failure leading to premature death if untreated. To further investigate the pathogenic mechanism and facilitate development of therapies pertaining to this variant, we applied CRISPR-Cas9 homology-directed repair (HDR) using a novel dual sgRNA approach flanking the target site to generate a GaaEm1935C>A knock-in mouse model as well as a myoblast cell line carrying the Gaa c.1935C>A mutation. Herein we describe the molecular, biochemical, physiological, histological, and behavioral characterization of 3-month-old homozygous GaaEm1935C>A mice. Homozygous GaaEm1935C>A knock-in mice exhibited normal Gaa mRNA expression levels relative to wild-type mice, but GAA enzymatic activity was almost completely abolished, leading to a substantial increase in tissue glycogen storage, and significant concomitant impairment of autophagy. Echocardiography of 3-month-old knock-in mice revealed significant cardiac hypertrophy. The mice also demonstrated skeletal muscle weakness but, paradoxically, not early mortality. Longitudinal studies of this model, including assessment of its immune response to exogenously supplied GAA enzyme, are currently underway. In summary, the GaaEm1935C>A knock-in mouse model recapitulates the molecular, biochemical, histopathologic, and phenotypic aspects of human IOPD caused by the GAA c.1935C>A pathogenic variant. It is an ideal model to assess innovative therapies to treat IOPD, including personalized therapeutic strategies that correct pathogenic variants, restore GAA activity and produce functional phenotypes.

genetics↗

bioRxiv2021

Multimodal tubulin binding by the yeast kinesin-8, Kip3, underlies its motility and depolymerization

The microtubule (MT) cytoskeleton is central to cellular processes including axonal growth, intracellular transport, and cell division, all of which rely on precise spatiotemporal control of MT organization. Kinesin-8s play a key role in regulating MT length by combining highly processive directional motility with MT-end disassembly. However, how kinesin-8 switches between these two apparently opposing activities remains unclear. Here, we define the structural features underlying this molecular switch through cryo-EM analysis of the yeast kinesin-8, Kip3 bound to MTs, and molecular dynamics simulations to approximate the complex of Kip3 with the curved tubulin state found at the MT plus-end. By integrating biochemical and single-molecule biophysical assays, we identified specific intra- and intermolecular interactions that modulate processive motility and MT disassembly. Our findings suggest that Kip3 undergoes conformational changes in response to tubulin curvature that underlie its unique ability to interact differently with the MT lattice than with the MT-end.

biophysics↗

bioRxiv2021

Revisiting the Hayflick Limit: Insights from an Integrated Analysis of Changing Transcripts, Proteins, Metabolites and Chromatin

The process wherein dividing cells exhaust proliferative capacity and enter into replicative senescence has become a prominent model for cellular aging in vitro. Despite decades of study, this cellular state is not fully understood in culture and even much less so during aging. Here, we revisit Leonard Hayflicks original observation of replicative senescence in WI-38 human lung fibroblasts equipped with a battery of modern techniques including RNA-seq, single cell RNA-seq, proteomics, metabolomics, and ATAC-seq. We find evidence that the transition to a senescent state manifests early, increases gradually, and corresponds to a concomitant global increase in DNA accessibility in nucleolar and lamin associated domains. Furthermore, we demonstrate that senescent WI-38 cells acquire a striking resemblance to myofibroblasts in a process similar to the epithelial to mesenchymal transition (EMT) that is regulated by the transcription factors YAP1/TEAD1 and TGF-{beta}2. Lastly, we show that verteporfin inhibition of YAP1/TEAD1 activity in aged WI-38 cells robustly attenuates this gene expression program.

genomics↗

bioRxiv2020

A genome-scale yeast library with inducible expression of individual genes

The ability to switch a gene from off to on and monitor dynamic changes provides a powerful approach for probing gene function and elucidating causal regulatory relationships, including instances of feedback control. Here, we developed and characterized YETI (Yeast Estradiol strains with Titratable Induction), a collection in which 5,687 yeast genes are engineered for transcriptional inducibility with single-gene precision at their native loci and without plasmids. Each strain contains Synthetic Genetic Array (SGA) screening markers and a unique molecular barcode, enabling high-throughput yeast genetics. We characterized YETI using quantitative growth phenotyping and pooled BAR-seq screens, and we used a YETI allele to characterize the regulon of ROF1, showing that it is a transcriptional repressor. We observed that strains with inducible essential genes that have low native expression can often grow without inducer. Analysis of data from other eukaryotic and prokaryotic systems shows that low native expression is a critical variable that can bias promoter-perturbing screens, including CRISPRi. We engineered a second expression system, Z3EB42, that gives lower expression than Z3EV, a feature enabling both conditional activation and repression of lowly expressed essential genes that grow without inducer in the YETI library.

synthetic biology↗

bioRxiv2019

CRISPR-Cas9 generated Pompe knock-in murine model exhibits early-onset cardiomyopathy and impaired skeletal muscle function

Infantile-onset Pompe Disease (IOPD), caused by mutations in lysosomal acid alpha-glucosidase (Gaa), manifests rapidly progressive fatal cardiac and skeletal myopathy incompletely attenuated by synthetic GAA intravenous infusions. The currently available murine model does not fully simulate human IOPD, displaying skeletal myopathy with late-onset hypertrophic cardiomyopathy. Bearing a Cre-LoxP induced exonic disruption of the murine Gaa gene, this model is also not amenable to genome-editing based therapeutic approaches. We report the early onset of severe hypertrophic cardiomyopathy in a novel murine IOPD model generated utilizing CRISPR-Cas9 homology-directed recombination to harbor the orthologous Gaa mutation c.1826dupA (p.Y609*), which causes human IOPD. We demonstrate the dual sgRNA approach with a single-stranded oligonucleotide donor is highly specific for the Gaac.1826 locus without genomic off-target effects or rearrangements. Cardiac and skeletal muscle were deficient in Gaa mRNA and enzymatic activity and accumulated high levels of glycogen. The mice demonstrated skeletal muscle weakness but did not experience early mortality. Altogether, these results demonstrate that the CRISPR-Cas9 generated Gaac.1826dupA murine model recapitulates hypertrophic cardiomyopathy and skeletal muscle weakness of human IOPD, indicating its utility for evaluation of novel therapeutics.

molecular biology↗