当前位置:首页 / 科学研究 / 实验室 / 正文

实验室

10:30-11:30, Monday, June 17, 2019


Speaker: Zeyu Chen, Ph.D.

John Wherry lab, Institute for Immunology

University of Pennsylvania

Topic: Dissecting the transcriptional network of CD8 T cell responses using in vivo CRISPR screening

Host:  Mo Xu, Ph.D.

Abstract

CD8 T cells play key roles during infectious diseases and cancer. During effector differentiation, memory formation and exhaustion of CD8 T cells, transcription factors (TF) can function as master regulators of cell fate by controlling lineage decisions and epigenetics. To dissect TF networks during T cell responses in a systematic high throughput manner, we developed Retroviral-based in vivo CRISPR screening system. Using this system, we performed library screening using 676 sgRNAs covering 112 transcription factors in the context of acute or chronic viral infection to interrogate effector versus exhaustion CD8 T cells and also gain insights into the biology or memory precursors. A loss-of-function screening approach identified Batf, Irf4, Myc as genes essential to initiate effector T cell response. We also defined Myb and Ets1 as key transcription factors regulating memory precursor differentiation whereas Smad4 and Smad7 were important for effector CD8 T cell responses. Furthermore, we found that Friend leukemia integration 1(Fli1) transcription factor was a novel TF regulating effector CD8 T cell biology. Genetic depletion of Fli1 greatly enhanced proliferation and expansion of antigen specific CD8 T cell in both acute and chronic infection whereas overexpression of Fli1 has the reverse effect, indicating a role for Fli1 in restraining T cell responses. Transcriptional and epigenetic identified potential mechanisms for the effect of Fli1 and support the notion of the Fli1 molecular circuitry as a therapeutic target. Overall, the establishment of this CRISPR screening system provides a high-throughput genetic perturbation platform to dissect molecular mechanism of T cell response in vivo. Using this system, we further functionally clarified the TF networks during T cell responses and identified potentially new candidates participating in T cell differentiation.