Honors & Awards
BioX Graduate Fellowship, Stanford BioX (2017-present)
GRFP, NSF (2017-present)
Engineered miniature CRISPR-Cas system for mammalian genome regulation and editing.
Compact and versatile CRISPR-Cas systems will enable genome engineering applications through high-efficiency delivery in a wide variety of contexts. Here, we create an efficient miniature Cas system (CasMINI) engineered from the type V-F Cas12f (Cas14) system by guide RNA and protein engineering, which is less than half the size of currently used CRISPR systems (Cas9 or Cas12a). We demonstrate that CasMINI can drive high levels of gene activation (up to thousands-fold increases), while the natural Cas12f system fails to function in mammalian cells. We show that the CasMINI system has comparable activities to Cas12a for gene activation, is highly specific, and allows robust base editing and gene editing. We expect that CasMINI can be broadly useful for cell engineering and gene therapy applications ex vivo and in vivo.
View details for DOI 10.1016/j.molcel.2021.08.008
View details for PubMedID 34480847
Multiple Input Sensing and Signal Integration Using a Split Cas12a System.
The ability to integrate biological signals and execute a functional response when appropriate is critical for sophisticated cell engineering using synthetic biology. Although the CRISPR-Cas system has been harnessed for synthetic manipulation of the genome, it has not been fully utilized for complex environmental signal sensing, integration, and actuation. Here, we develop a split dCas12a platform and show that it allows for the construction of multi-input, multi-output logic circuits in mammalian cells. The system is highly programmable and can generate expandable AND gates with two, three, and four inputs. It can also incorporate NOT logic by using anti-CRISPR proteins as an OFF switch. By coupling the split dCas12a design to multiple tumor-relevant promoters, we provide a proof of concept that the system can implement logic gating to specifically detect breast cancer cells and execute therapeutic immunomodulatory responses.
View details for DOI 10.1016/j.molcel.2020.01.016
View details for PubMedID 32027839
- When genome editing goes off-target SCIENCE 2019; 364 (6437): 234–36
Chd8 Mutation Leads to Autistic-like Behaviors and Impaired Striatal Circuits
2017; 19 (2): 335-350
Autism spectrum disorder (ASD) is a heterogeneous disease, but genetically defined models can provide an entry point to studying the molecular underpinnings of this disorder. We generated germline mutant mice with loss-of-function mutations in Chd8, a de novo mutation strongly associated with ASD, and demonstrate that these mice display hallmark ASD behaviors, macrocephaly, and craniofacial abnormalities similar to patient phenotypes. Chd8(+/-) mice display a broad, brain-region-specific dysregulation of major regulatory and cellular processes, most notably histone and chromatin modification, mRNA and protein processing, Wnt signaling, and cell-cycle regulation. We also find altered synaptic physiology in medium spiny neurons of the nucleus accumbens. Perturbation of Chd8 in adult mice recapitulates improved acquired motor learning behavior found in Chd8(+/-) animals, suggesting a role for CHD8 in adult striatal circuits. These results support a mechanism linking chromatin modification to striatal dysfunction and the molecular pathology of ASD.
View details for DOI 10.1016/j.celrep.2017.03.052
View details for Web of Science ID 000401132600010
View details for PubMedID 28402856
CRISPR-Cas9 Knockin Mice for Genome Editing and Cancer Modeling
2014; 159 (2): 440-455
CRISPR-Cas9 is a versatile genome editing technology for studying the functions of genetic elements. To broadly enable the application of Cas9 in vivo, we established a Cre-dependent Cas9 knockin mouse. We demonstrated in vivo as well as ex vivo genome editing using adeno-associated virus (AAV)-, lentivirus-, or particle-mediated delivery of guide RNA in neurons, immune cells, and endothelial cells. Using these mice, we simultaneously modeled the dynamics of KRAS, p53, and LKB1, the top three significantly mutated genes in lung adenocarcinoma. Delivery of a single AAV vector in the lung generated loss-of-function mutations in p53 and Lkb1, as well as homology-directed repair-mediated Kras(G12D) mutations, leading to macroscopic tumors of adenocarcinoma pathology. Together, these results suggest that Cas9 mice empower a wide range of biological and disease modeling applications.
View details for DOI 10.1016/j.cell.2014.09.014
View details for Web of Science ID 000343095600023
View details for PubMedID 25263330
View details for PubMedCentralID PMC4265475