Harvard College

Monsanto Company

Ahmed Hussein Badran

David R Liu

Kevin Michael Esvelt

Michael S Packer

Jacob Charles Carlson

Bryan Dickinson

Basil Hubbard

Victor M Guzov

Prashanth Vishwanath

Qing Huai

Tina Wang

Tom Malvar

Jeff Nageotte

Melissa Kemp

Strategies, systems, methods, reagents, and kits for phage-assisted continuous evolution are provided herein. These include strategies, systems, methods, reagents, and kits allowing for stringency modulation to evolve weakly active or inactive biomolecule variants, negative selection of undesired properties, and/or positive selection of desired properties.

Negative selection and stringency modulation in continuous evolution systems

Engineered transcriptional activator-like effectors (TALEs) are versatile tools for genome manipulation with applications in research and clinical contexts. One current drawback of TALEs is that the 5′ nucleotide of the target is specific for thymine (T). TALE domains with alternative 5′ nucleotide specificities could expand the scope of DNA target sequences that can be bound by TALEs. Another drawback of TALEs is their tendency to bind and cleave off-target sequence, which hampers their clinical application and renders applications requiring high-fidelity binding unfeasible. This disclosure provides methods and strategies for the continuous evolution of proteins comprising DNA-binding domains, e.g., TALE domains. In some aspects, this disclosure provides methods and strategies for evolving such proteins under positive selection for a desired DNA-binding activity and/or under negative selection against one or more undesired (e.g., off-target) DNA-binding activities. Some aspects of this disclosure provide engineered TALE domains and TALEs comprising such engineered domains, e.g., TALE nucleases (TALENs), TALE transcriptional activators, TALE transcriptional repressors, and TALE epigenetic modification enzymes, with altered 5′ nucleotide specificities of target sequences. Engineered TALEs that target ATM with greater specificity are also provided.

Evolution of TALENs

Some aspects of this disclosure provide methods for phage-assisted continuous evolution (PACE) of proteases. Some aspects of this invention provide methods for evaluating and selecting protease inhibitors based on the likelihood of the emergence of resistant proteases as determined by the protease PACE methods provided herein. Some aspects of this disclosure provide strategies, methods, and reagents for protease PACE, including fusion proteins for translating a desired protease activity into a selective advantage for phage particles encoding a protease exhibiting such an activity and improved mutagenesis-promoting expression constructs. Evolved proteases that recognize target cleavage sites which differ from their canonical cleavage site are also provided herein.

Evolution of proteases

Some aspects of this disclosure relate to systems, apparatuses, compositions (e.g., isolated nucleic acids and vectors), and methods for improving the stability and/or solubility of proteins evolved using phage-assisted continuous evolution (PACE). In some embodiments, vectors described herein comprise nucleic acids encoding selection systems (e.g., positive and/or negative selection systems) that link expression of genes required for production of infectious phage particles to a desirable physiochemical (e.g., stability or solubility) and/or desired function of an evolved protein.

Continuous evolution for stabilized proteins

The disclosure provides amino acid sequence variants of(Bt) toxins and methods of producing the same. Some aspects of this disclosure provide methods for generating Bt toxin variants by continuous directed evolution. Some aspects of this disclosure provide compositions and methods for pest control using the disclosed variant Bt toxins.

Evolution oftoxins

Strategies, reagents, methods, and systems for modulating the mutation rate in cells are provided herein. The strategies, reagents, methods, and systems are broadly applicable for the modulation of mutation rates in cells where high mutation rates and/or control over a broad range of mutation rates is desired, for example, in the context of diversifying a nucleic acid sequence or a plurality of such sequences within a population of cells, for the generation of diversified nucleic acid libraries, and for directed evolution of nucleic acids and encoded products.

Vector-based mutagenesis system

Engineered transcriptional activator-like effectors (TALEs) are versatile tools for genome manipulation with applications in research and clinical contexts. One current drawback of TALEs is that the 5' nucleotide of the target is specific for thymine (T). TALE domains with alternative 5&#x2032; nucleotide specificities could expand the scope of DNA target sequences that can be bound by TALEs. Another drawback of TALEs is their tendency to bind and cleave off-target sequence, which hampers their clinical application and renders applications requiring high-fidelity binding unfeasible. This disclosure provides methods and strategies for the continuous evolution of proteins comprising DNA-binding domains, e.g., TALE domains. In some aspects, this disclosure provides methods and strategies for evolving such proteins under positive selection for a desired DNA-binding activity and/or under negative selection against one or more undesired (e.g., off-target) DNA-binding activities. Some aspects of this disclosure provide engineered TALE domains and TALEs comprising such engineered domains, e.g., TALE nucleases (TALENs), TALE transcriptional activators, TALE transcriptional repressors, and TALE epigenetic modification enzymes, with altered 5&#x2032; nucleotide specificities of target sequences. Engineered TALEs that target ATM with greater specificity are also provided.

Engineered transcriptional activator-like effectors (TALEs) are versatile tools for genome manipulation with applications in research and clinical contexts. One current drawback of TALEs is that the 5' nucleotide of the target is specific for thymine (T). TALE domains with alternative 5&#x2032; nucleotide specificities could expand the scope of DNA target sequences that can be bound by TALEs. This disclosure provides methods and strategies for the continuous evolution of proteins comprising DNA-binding domains, e.g., TALE domains. In some aspects, this disclosure provides methods and strategies for evolving such proteins under positive selection for a desired DNA-binding activity and/or under negative selection against one or more undesired (e.g., off-target) DNA-binding activities. Some aspects of this disclosure provide engineered TALE domains and TALEs comprising such engineered domains, e.g., TALE nucleases (TALENs), TALE transcriptional activators, TALE transcriptional repressors, and TALE epigenetic modification enzymes, with altered 5&#x2032; nucleotide specificities of target sequences. Engineered TALEs that target ATM with greater specificity are also provided.

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Somerville, MA, United States of America

Ahmed Hussein Badran