Various aspects and embodiments of the present disclosure are directed to methods and compositions for functionalizing endogenous bacteria in vivo. The methods include delivering to endogenous bacterial cells a recombinant bacteriophage or phagemid that is engineered to contain at least one genetic circuit.

The invention relates to the methods for modifying the methylation pattern of bacteriophage DNA and phagemid DNA and to methods for selective killing of bacteria using lysogenic bacteriophages comprising bacteriophage DNA or phagemid DNA comprising components of an engineered CRISPR-Cas system.

The invention provides hybrid and recombinant phagemid vectors for expressing a transgene in a target cell transduced with the vector. A recombinant phagemid particle comprises at least one transgene expression cassette which encodes an agent which exerts a biological effect on the target cell, characterised in that the phagemid particle comprises a genome which lacks at least 50% of its bacteriophage genome. The invention extends to the use of such phagemid expression systems as a research tool, and for the delivery of transgenes in a variety of gene therapy applications, DNA and/or peptide vaccine delivery and imaging techniques. The invention extends to in vitro, in vivo or in situ methods for producing viral vectors, such as recombinant adeno-associated viruses (rAAV) or lentivirus vectors (rLV), and to genetic constructs used in such methods.

Compositions for a phage particle are disclosed. The phage particle is non-replicating and includes at least one heterologous nucleic acid sequence that is capable of being expressed in a target bacteria. The expressed heterologous nucleic acid sequence is non-lethal to the target bacteria.

Some aspects of the present disclosure provide methods for evolving recombinases to recognize target sequences that differ from the canonical recognition sequences. Some aspects of this disclosure provide evolved recombinases, e.g., recombinases that bind and recombine naturally-occurring target sequences, such as, e.g., target sequences within the human Rosa26 locus. Methods for using such recombinases for genetically engineering nucleic acid molecules in vitro and in vivo are also provided. Some aspects of this disclosure also provide libraries and screening methods for assessing the target site preferences of recombinases, as well as methods for selecting recombinases that bind and recombine a non-canonical target sequence with high specificity.

Provided are amino acid sequences capable of binding to and inhibiting a Cas protein's ability to bind to a nucleic acid molecule, thereby inhibiting the Cas protein's function in genome editing. Such Cas protein inhibitors, which can be comprised of a major coat protein (G8P), an extracellular region of the G8P (G8P.sub.EX), or a biological equivalent, are useful in improving the specificity of Cas protein-based genome editing procedures.

The present invention relates to a plasmid-based CTX phage replication system and Vibrio cholerae strain that can be infected by CTX phage and can be used for cholera toxin production. More particularly, the present invention provides a Vibrio cholera variant strain, which expresses a toxT protein in which tyrosine at position 139 is substituted by phenylalanine through the point mutation of a toxT gene using a plasmid-based CTX phage replication system, and is used as a receptor strain which can improve CTX phage infection efficiency and allows a plurality of CTX prophages to simultaneously infect the strain and to be inserted into the chromosome thereof, which the consequent provision of the effect of increasing the production yield of a cholera toxin.

Some aspects of the present disclosure provide methods for evolving recombinases to recognize target sequences that differ from the canonical recognition sequences. Some aspects of this disclosure provide evolved recombinases, e.g., recombinases that bind and recombine naturally-occurring target sequences, such as, e.g., target sequences within the human Rosa26 locus. Methods for using such recombinases for genetically engineering nucleic acid molecules in vitro and in vivo are also provided. Some aspects of this disclosure also provide libraries and screening methods for assessing the target site preferences of recombinases, as well as methods for selecting recombinases that bind and recombine a non-canonical target sequence with high specificity.

The disclosure provides amino acid sequence variants of Botulinum neurotoxin (BoNT) proteases that cleave (VAMP1, VAMP2, VAMP7, VAMP8, SNAP25, SNAP23, PTEN, etc.) and methods of evolving the same. In some embodiments, proteases described by the disclosure are useful for cleaving proteins found in a cell, that is in an intracellular environment. In some embodiments, proteases described by the disclosure are useful for treating diseases associated with increased or aberrant VAMP7, VAMP8, SNAP23 or PTEN expression or activity, for example, cancer and neurological disorders. Some aspects of this disclosure provide methods for generating BoNT protease variants by continuous directed evolution.

Various aspects and embodiments of the present disclosure are directed to methods and compositions for functionalizing endogenous bacteria in vivo. The methods include delivering to endogenous bacterial cells a recombinant bacteriophage or phagemid that is engineered to contain at least one genetic circuit.