"Systematic discovery of natural CRISPR-Cas12a inhibitors" and "Discovery of widespread Type I and Type V CRISPR-Cas inhibitors"

Date: 
September 19, 2018
Place: 
HSW 1057

Abstract

Cas12a (Cpf1) is a CRISPR-associated nuclease with broad utility for synthetic genome engineering, agricultural genomics, and biomedical applications. While bacteria harboring CRISPR-Cas9 or CRISPR-Cas3 adaptive immune systems sometimes acquire mobile genetic elements encoding anti-CRISPR proteins that inhibit Cas9, Cas3, or the DNA-binding Cascade complex, no such inhibitors have been found for CRISPR-Cas12a. Here we employ a comprehensive bioinformatic and experimental screening approach to identify three different inhibitors that block or diminish CRISPR-Cas12a-mediated genome editing in human cells. We also find a widespread connection between CRISPR self-targeting and inhibitor prevalence in prokaryotic genomes, suggesting a straightforward path to the discovery of many more anti-CRISPRs from the microbial world.

Abstract

Bacterial CRISPR-Cas systems protect their host from bacteriophages and other mobile genetic elements. Mobile elements, in turn, encode various anti-CRISPR (Acr) proteins to inhibit the immune function of CRISPR-Cas. To date, Acr proteins have been discovered for type I (subtypes I-D, I-E, and I-F) and type II (II-A and II-C) but not other CRISPR systems. Here we report the discovery of 12 acr genes, including inhibitors of type V-A and I-C CRISPR systems. Notably, AcrVA1 inhibits a broad spectrum of Cas12a (Cpf1) orthologs including MbCas12a, Mb3Cas12a, AsCas12a, and LbCas12a when assayed in human cells. The acr genes reported here provide useful biotechnological tools and mark the discovery of acr loci in many bacteria and phages.

Presenter: 
Yuhao Wang
Publication Date: 
September 6, 2018
Presentation Paper: 
Time: 
12:00pm
Paper Author: 
First paper: Watters KE1, Fellmann C1,2, Bai HB1, Ren SM1, Doudna JA3,2,4,5,6,7,8.
Second paper: Marino ND1, Zhang JY1, Borges AL1, Sousa AA2,3,4, Leon LM1, Rauch BJ1, Walton RT2,3,4, Berry JD1, Joung JK2,3,4,5, Kleinstiver BP2,3,4,5, Bondy-Denomy J6,7.
Institution: 
First paper:
1 Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
2 Gladstone Institutes, San Francisco, CA 94158, USA.
3 Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA. [email protected]
4 Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA.
5 Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
6 Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
7 Li Ka Shing Biomedical and Health Sciences Center, University of California, Berkeley, Berkeley, CA 94720, USA.
8 Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.

Second paper:
1 Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA.
2 Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, MA 02129, USA.
3 Center for Cancer Research, Massachusetts General Hospital, Charlestown, MA 02129, USA.
4 Center for Computational and Integrative Biology, Massachusetts General Hospital, Charlestown, MA 02129, USA.
5 Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
6 Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA. [email protected]
7 Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94143, USA.
Journal: 
First paper: Science. 2018 Sep 6. pii: eaau5138. doi: 10.1126/science.aau5138. [Epub ahead of print]. Second Paper: Science. 2018 Sep 6. pii: eaau5174. doi: 10.1126/science.aau5174. [Epub ahead of print]