Publications by authors named "King L Hung"

4 Publications

  • Page 1 of 1

Genome-wide programmable transcriptional memory by CRISPR-based epigenome editing.

Cell 2021 Apr 9;184(9):2503-2519.e17. Epub 2021 Apr 9.

Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge 02142, USA. Electronic address:

A general approach for heritably altering gene expression has the potential to enable many discovery and therapeutic efforts. Here, we present CRISPRoff-a programmable epigenetic memory writer consisting of a single dead Cas9 fusion protein that establishes DNA methylation and repressive histone modifications. Transient CRISPRoff expression initiates highly specific DNA methylation and gene repression that is maintained through cell division and differentiation of stem cells to neurons. Pairing CRISPRoff with genome-wide screens and analysis of chromatin marks establishes rules for heritable gene silencing. We identify single guide RNAs (sgRNAs) capable of silencing the large majority of genes including those lacking canonical CpG islands (CGIs) and reveal a wide targeting window extending beyond annotated CGIs. The broad ability of CRISPRoff to initiate heritable gene silencing even outside of CGIs expands the canonical model of methylation-based silencing and enables diverse applications including genome-wide screens, multiplexed cell engineering, enhancer silencing, and mechanistic exploration of epigenetic inheritance.
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http://dx.doi.org/10.1016/j.cell.2021.03.025DOI Listing
April 2021

A functional taxonomy of tumor suppression in oncogenic KRAS-driven lung cancer.

Cancer Discov 2021 Feb 19. Epub 2021 Feb 19.

Department of Genetics, Stanford University School of Medicine

Cancer genotyping has identified a large number of putative tumor suppressor genes. Carcinogenesis is a multi-step process, however the importance and specific roles of many of these genes during tumor initiation, growth and progression remain unknown. Here we use a multiplexed mouse model of oncogenic KRAS-driven lung cancer to quantify the impact of forty-eight known and putative tumor suppressor genes on diverse aspects of carcinogenesis at an unprecedented scale and resolution. We uncover many previously understudied functional tumor suppressors that constrain cancer in vivo. Inactivation of some genes substantially increased growth, while the inactivation of others increases tumor initiation and/or the emergence of exceptionally large tumors. These functional in vivo analyses revealed an unexpectedly complex landscape of tumor suppression that has implications for understanding cancer evolution, interpreting clinical cancer genome sequencing data, and directing approaches to limit tumor initiation and progression.
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http://dx.doi.org/10.1158/2159-8290.CD-20-1325DOI Listing
February 2021

Engineering Protein-Secreting Plasma Cells by Homology-Directed Repair in Primary Human B Cells.

Mol Ther 2018 02 22;26(2):456-467. Epub 2017 Nov 22.

Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, Washington, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, USA. Electronic address:

The ability to engineer primary human B cells to differentiate into long-lived plasma cells and secrete a de novo protein may allow the creation of novel plasma cell therapies for protein deficiency diseases and other clinical applications. We initially developed methods for efficient genome editing of primary B cells isolated from peripheral blood. By delivering CRISPR/CRISPR-associated protein 9 (Cas9) ribonucleoprotein (RNP) complexes under conditions of rapid B cell expansion, we achieved site-specific gene disruption at multiple loci in primary human B cells (with editing rates of up to 94%). We used this method to alter ex vivo plasma cell differentiation by disrupting developmental regulatory genes. Next, we co-delivered RNPs with either a single-stranded DNA oligonucleotide or adeno-associated viruses containing homologous repair templates. Using either delivery method, we achieved targeted sequence integration at high efficiency (up to 40%) via homology-directed repair. This method enabled us to engineer plasma cells to secrete factor IX (FIX) or B cell activating factor (BAFF) at high levels. Finally, we show that introduction of BAFF into plasma cells promotes their engraftment into immunodeficient mice. Our results highlight the utility of genome editing in studying human B cell biology and demonstrate a novel strategy for modifying human plasma cells to secrete therapeutic proteins.
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http://dx.doi.org/10.1016/j.ymthe.2017.11.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5835153PMC
February 2018

Wnt signaling and tbx16 form a bistable switch to commit bipotential progenitors to mesoderm.

Development 2015 Jul 10;142(14):2499-507. Epub 2015 Jun 10.

Department of Biochemistry, University of Washington, Seattle, WA 98195, USA

Anterior to posterior growth of the vertebrate body is fueled by a posteriorly located population of bipotential neuro-mesodermal progenitor cells. These progenitors have a limited rate of proliferation and their maintenance is crucial for completion of the anterior-posterior axis. How they leave the progenitor state and commit to differentiation is largely unknown, in part because widespread modulation of factors essential for this process causes organism-wide effects. Using a novel assay, we show that zebrafish Tbx16 (Spadetail) is capable of advancing mesodermal differentiation cell-autonomously. Tbx16 locks cells into the mesodermal state by not only activating downstream mesodermal genes, but also by repressing bipotential progenitor genes, in part through a direct repression of sox2. We demonstrate that tbx16 is activated as cells move from an intermediate Wnt environment to a high Wnt environment, and show that Wnt signaling activates the tbx16 promoter. Importantly, high-level Wnt signaling is able to accelerate mesodermal differentiation cell-autonomously, just as we observe with Tbx16. Finally, because our assay for mesodermal commitment is quantitative we are able to show that the acceleration of mesodermal differentiation is surprisingly incomplete, implicating a potential separation of cell movement and differentiation during this process. Together, our data suggest a model in which high levels of Wnt signaling induce a transition to mesoderm by directly activating tbx16, which in turn acts to irreversibly flip a bistable switch, leading to maintenance of the mesodermal fate and repression of the bipotential progenitor state, even as cells leave the initial high-Wnt environment.
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http://dx.doi.org/10.1242/dev.124024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510867PMC
July 2015