Epigenetic modifications, such as DNA methylation and histone acetylation/methylation, play a critical role in dictating the function and behavior of an organism. Efforts to unravel the workings of the epigenome, however, are constrained by severe technical limitations in our ability to manipulate chromatin modifications. Existing approaches typically involve pharmacological agents or genetic modification and tend to have pleiotropic effects. This proposal aims to develop a universal set of tools for manipulating epigenetic modifications capable of targeting specific chromatin modifiers to any desired locus and precisely controlling the timing and magnitude of these modifications. The proposed platform is built on our recently demonstrated CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) interference system-a highly efficient RNA- guided genome-targeting system derived from the CRISPR bacterial immune system. The method requires only a single protein, dCas9, a catalytically inactive variant of the CRISPR Cas9 proteins, and a designed small guide RNA (sgRNA) with a region that is complementary to the gene of interest. The sgRNA guides binding of the dCas9-sgRNA complex to the complementary genomic site. We will develop a CRISPR RNA-based toolset for targeted and inducible manipulation of the epigenetic modifications First, we will develop a series of optimized dCas9-sgRNA pairs in which the DNA location of targeting is determined solely by the sequence of the sgRNA and the epigenetic impact of targeting is dictated by the effector domain that is recruited by dCas9. This will then be coupled with a genome-wide library of sgRNAs capable of targeting the dCas9 at will to roughly 100,000 positions in the human genome. Second, to enable inducible epigenetic controls, we will fuse the dCas9 proteins to a complement of diverse epigenetic modifier domains and effector domains that can be controlled by light or drugs. The epigenetic modifier domains will contain different catalytic and/or regulatory domains derived from natural epigenetic regulators, including both writer and eraser modules. Optogenetically and chemically gated interaction modules will be used to achieve spatial and temporal control. Third, we will apply these tools to a small set of pilot mechanistic and bioengineering studies to test how the CRISPR epigenetic toolbox can be utilized. Specifically, we will modify the epigenetic marks of the murine Oct4 and Sox2 loci as the endogenous experimental testbed, and study the importance of modifier recruitment positioning and dynamics in controlling chromatin state. Finally, we will develop programmable CRISPR insulators to control long-range chromatin interactions of human beta globin expression. Together, this project will provide a universal RNA-guided platform for precise spatial and temporal regulation of the epigenome. We envision this platform will be a critical tool for studying the interplay between multiple epigenetic modifirs at different loci, understanding the relationship between epigenomic programming and disease, and facilitate the development of therapeutic methods to rewrite and reprogram epigenetic marks.
The human epigenome, governing the chromatin structure organization and DNA or histone modifications, encodes important information related to human physiology and diseases, yet we lack effective methods to manipulate the epigenome, hindering efforts to unravel the principles underlying epigenetic control. To address this deficiency, the proposed research aims to develop a universal RNA-guided platform for precise spatial and temporal regulation of the epigenome, which will be widely applicable to write and erase multiple epigenetic marks for almost any endogenous genomic locus. These capabilities will be critical for studying the interplay between multiple epigenetic modifiers at different loci, understanding the relationship between epigenomic programming and disease, and facilitating the development of therapeutic methods to rewrite and reprogram epigenetic marks.
|Jost, Marco; Chen, Yuwen; Gilbert, Luke A et al. (2017) Combined CRISPRi/a-Based Chemical Genetic Screens Reveal that Rigosertib Is a Microtubule-Destabilizing Agent. Mol Cell 68:210-223.e6|
|Du, Dan; Roguev, Assen; Gordon, David E et al. (2017) Genetic interaction mapping in mammalian cells using CRISPR interference. Nat Methods 14:577-580|
|Liu, S John; Horlbeck, Max A; Cho, Seung Woo et al. (2017) CRISPRi-based genome-scale identification of functional long noncoding RNA loci in human cells. Science 355:|
|Peters, Jason M; Colavin, Alexandre; Shi, Handuo et al. (2016) A Comprehensive, CRISPR-based Functional Analysis of Essential Genes in Bacteria. Cell 165:1493-1506|
|Chen, Baohui; Hu, Jeffrey; Almeida, Ricardo et al. (2016) Expanding the CRISPR imaging toolset with Staphylococcus aureus Cas9 for simultaneous imaging of multiple genomic loci. Nucleic Acids Res 44:e75|
|Xiong, Xin; Chen, Meng; Lim, Wendell A et al. (2016) CRISPR/Cas9 for Human Genome Engineering and Disease Research. Annu Rev Genomics Hum Genet 17:131-54|
|Horlbeck, Max A; Gilbert, Luke A; Villalta, Jacqueline E et al. (2016) Compact and highly active next-generation libraries for CRISPR-mediated gene repression and activation. Elife 5:|
|Horlbeck, Max A; Witkowsky, Lea B; Guglielmi, Benjamin et al. (2016) Nucleosomes impede Cas9 access to DNA in vivo and in vitro. Elife 5:|
|Qin, Han; Hejna, Miroslav; Liu, Yanxia et al. (2016) YAP Induces Human Naive Pluripotency. Cell Rep 14:2301-12|
|Nguyen, Duy P; Miyaoka, Yuichiro; Gilbert, Luke A et al. (2016) Ligand-binding domains of nuclear receptors facilitate tight control of split CRISPR activity. Nat Commun 7:12009|
Showing the most recent 10 out of 32 publications