Method of constructing gene transport support

A gene delivery carrier consisting of a bacterium of the genus Bifidobacterium transformed with an expression vector comprising:

• (i) a fragment of a plasmid of a bacterium of the genus Bifidobacterium;
• (ii) a fragment of a plasmid of Escherichia coli;
• (iii) 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;
• and
• (iv) a DNA encoding cytosine deaminase positioned between the promoter and the terminator, wherein the DNA comprises:
• (a) a DNA sequence encoding an amino acid sequence which:
• (1) deletes methionine at position 1;
• and (2) 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).

A cytosine deaminase-highly-expressing unit comprising a

• DNA fragment comprising:
• (i) a promoter and a terminator of the gene encoding the histone-like DNA-binding protein derived from a bacterium of the genus Bifidobacterium;
• and
• (ii) a DNA encoding cytosine deaminase positioned between the promoter and the terminator, wherein the DNA comprises:
• (a) a DNA sequence encoding an amino acid sequence which:
• (1) deletes methionine at position 1;
• and (2) 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).

A cytosine deaminase-highly-expressing unit comprising a DNA fragment comprising:

• (i) a promoter and a terminator of the gene encoding the histone-like DNA-binding protein derived from a bacterium of the genus Bifidobacterium;
• and
• (ii) a DNA encoding cytosine deaminase positioned between the promoter and the terminator, wherein the DNA comprises:
• (a) a DNA sequence encoding an amino acid sequence which:
• (1) deletes methionine at position 1;
• and (2) 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 the amino acid sequence corresponding to positions 1 through 9 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).