Patent ID: 8911721

Claim:
A method of constructing a gene delivery carrier consisting of a bacterium of the genus Bifidobacterium transformed with an expression vector, comprising the steps of: (1) preparing a fusion plasmid having a fragment of a plasmid of a bacterium of the genus Bifidobacterium and a fragment of a plasmid of Escherichia coli; (2) incorporating a DNA fragment comprising a promoter and a terminator of the gene encoding the histone-like DNA-binding protein derived from a bacterium of the genus Bifidobacterium into the fusion plasmid; (3) incorporating, between the promoter and the terminator, a DNA encoding cytosine deaminase to obtain the expression vector, wherein the DNA comprises: (a) a DNA sequence encoding an amino acid sequence which: (i) deletes methionine at position 1; and (ii) replaces aspartic acid at position 315 with alanine from the amino acid sequence set forth in SEQ ID NO:28; and (b) a DNA sequence which encodes an amino acid sequence corresponding to positions 1 through at least 4 and up to a maximum of 18 amino acids of the histone-like DNA binding protein as set forth in SEQ ID NO: 29 and which is linked to (a) on the 5′-terminal side of (a); and (4) transforming the bacterium of the genus Bifidobacterium with the expression vector.