Single-vector type I vectors

A cell of a production strain of Escherichia coli (E. coli) cells, comprising a first DNA construct wherein:

• the first DNA construct comprises a nucleotide sequence encoding a Cas nuclease, wherein the nucleotide sequence is under the control of a promoter for controlling the expression of the Cas nuclease in the production strain cell, wherein
• the first DNA construct comprises an origin of replication that is operable in the cell for replication of the construct;
• the promoter comprises a nucleotide sequence that is capable of binding to a repressor;
• wherein the production strain cell comprises a nucleic acid encoding the repressor;
• wherein the promoter is capable of being repressed by the repressor in the production strain;
• wherein the cell of the production strain comprises amplified copies of the first DNA construct, wherein the amplified copies of the first DNA construct do not comprise the nucleic acid encoding the repressor,
• wherein the nucleic acid encoding the repressor is a chromosomally-integrated sequence or comprised by a second DNA construct;
• and
• wherein the nucleic acid encoding the repressor is capable of expressing the repressor in the cell of the production strain comprising the amplified copies of the first DNA construct;
• wherein the cell of the production strain comprises a nucleotide sequence whose expression is inducible to produce phage coat proteins in the cell of the production strain,
• wherein the cell of the production strain is capable of packaging the amplified copies of the first DNA construct into phage particles or non-self-replicative transduction particles for introducing the first DNA into a target host cell, and wherein the phage particles or non-self-replicative transduction particles are devoid of a nucleotide sequence encoding the repressor;
• and
• wherein the Cas nuclease is operable with one or more crRNAs or gRNAs to cut target nucleotide sequences in the target host cell, and wherein the production strain cell does not comprise a crRNA or gRNA operable with the Cas nuclease to target and cut a chromosomal sequence of the production strain cell.