Hybrid proteins and uses thereof

A method of delivering a DNA plasmid into a eukaryotic target cell, the method comprising:

• (a) providing a transformed Bifidobacteria sp. bacterium comprising the DNA plasmid, the DNA plasmid comprising (i) an origin of replication that is functional in the Bifidobacteria sp. bacterium, (ii) a eukaryotic expression cassette which expresses a cargo sequence in a eukaryotic cell, and (iii) a prokaryotic expression cassette for expression in the Bifidobacteria sp. bacterium comprising a polynucleotide sequence encoding a hybrid protein, the hybrid protein comprising:
• at least one Bifidobacteria secretion signal sequence directing secretion of a protein:DNA plasmid complex from the transformed Bifidobacteria sp. bacterium;
• at least one DNA binding domain which binds to the DNA plasmid, the at least one DNA binding domain positioned C-terminal in the hybrid protein relative to the at least one Bifidobacteria secretion signal sequence;
• and
• at least one cell penetrating peptide (CPP) domain positioned C-terminal in the hybrid protein relative to the at least one DNA binding domain;
• (b) expressing the hybrid protein from the DNA plasmid and replicating the DNA plasmid in the transformed Bifidobacteria sp. bacterium of step (a) to form the protein:DNA plasmid complex, whereby the protein:DNA plasmid is secreted out of the transformed Bifidobacteria sp. bacterium;
• and
• (c) contacting the eukaryotic target cell with the protein:DNA plasmid complex secreted in step (b).