University of Massachusetts

The Governing Council of the University of Toronto

Wisconsin Alumni Research Foundation

Northwestern University

Erik J Sontheimer

Nadia Amrani

Yan Zhang

Scot Andrew Wolfe

Mehmet Fatih Bolukbasi

Ankit Gupta

Craig C Mello

Jonathan Watts

Karen Maxwell

Rakhi Rajan

Krishna Sumanth Ghanta

Alan Davidson

Hassan Gneid

Gregoriy Dokshin

Aamir Mir

Jooyoung Lee

April Pawluk

Alfonso Mondragon

Many strains of the human pathogencarry a compact Cas9 (NmeCas9) that can serve to limit genetic exchange via natural transformation. Cas9 orthologues (including NmeCas9) have recently been adopted for RNA-guided genome engineering and DNA binding, adding to the need to define better their activities and properties. The present invention examines DNA cleavage activities and substrate requirements of NmeCas9, including a set of unusually complex PAM recognition patterns. Unexpectedly, NmeCas9 is found able to cleave single-stranded DNA (ssDNA) targets in a manner that is RNA-guided but both PAM- and tracrRNA-independent. Beyond the requirement for guide-target pairing, this activity has no apparent sequence requirements, and the cleavage sites are measured from the 5' end of the DNA substrate's RNA-paired region. These results indicate that tracrRNA domains are not strictly required for enzymatic activation of NmeCas9, and expand the list of targeting activities exhibited by these revolutionary RNA-guided nucleases.

DNase H activity of Neisseria meningitidis Cas9

The disclosure provides novel methods and compositions for gene editing. In particular, the disclosure relates to compositions and methods of making modified nucleic acid donor templates for highly efficient and precise gene editing.

Compositions and methods for improved gene editing

The present invention is related to the field of CRISPR-Cas9 gene editing platforms. In particular, the present invention has identified Type II-C Cas9 anti-CRISPR (Acr) inhibitors that control Cas9 gene editing activity. Co-administration of such Acr inhibitors may provide an advantageous adjunct in permitting safe and practical biological therapeutics through spatial or temporal control of Cas9 activity; controlling Cas9-based gene drives in wild populations to reduce the ecological consequences of such forced inheritance schemes; and contributing to general research into various biotechnological, agricultural, and medical applications of gene editing technologies.

Anti-CRISPR compounds and methods of use

The present invention provides a Cas9 platform to facilitate single-site nuclease gene editing precision within a human genome. For example, a Cas9 nuclease/DNA-targeting unit (Cas9-DTU) fusion protein precisely delivers a Cas9/sgRNA complex to a specific target site within the genome for subsequent sgRNA-dependent cleavage of an adjacent target sequence. Alternatively, attenuating Cas9 binding using mutations to the a protospacer adjacent motif (PAM) recognition domain makes Cas9 target site recognition dependent on the associated DTU, all while retaining Cas9's sgRNA-mediated DNA cleavage fidelity. Cas9-DTU fusion proteins have improved target site binding precision, greater nuclease activity, and a broader sequence targeting range than standard Cas9 systems. Existing Cas9 or sgRNA variants (e.g., truncated sgRNAs (tru-gRNAs), nickases and FokI fusions) are compatible with these improvements to further reduce off-target cleavage. A robust, broadly applicable strategy is disclosed to impart Cas9 genome-editing systems with the single-genomic-site accuracy needed for safe, effective clinical application.

CAS9-CAS9 fusion proteins

Cas9-DNA targeting unit chimeras

Growing community of inventors

Auburndale, MA, United States of America

Erik J Sontheimer