Method for increasing mutation introduction efficiency in genome sequence modification technique, and molecular complex to be used therefor

A method of modifying a targeted site of a double-stranded DNA, comprising a step of contacting a complex wherein a nucleic acid sequence-recognizing module that specifically binds to a target nucleotide sequence in a given double-stranded DNA, a nucleic acid base converting enzyme and a base excision repair inhibitor are bonded, with said double-stranded DNA to convert one or more nucleotides in the targeted site to other one or more nucleotides or delete one or more nucleotides, or insert one or more nucleotides into said targeted site, without cleaving at least one strand of said double-stranded DNA in the targeted site,

• wherein the nucleic acid sequence-recognizing module is a CRISPR-Cas system wherein at least one DNA cleavage ability of Cas is inactivated,
• wherein said nucleic acid base converting enzyme is Petromyzon marinus cytosine deaminase 1 (PmCDA1);
• wherein the PmCDA1 has the amino acid sequence set forth in SEQ ID NO:
• 2,
• wherein the PmCDA1 is fused to the nucleic acid sequence-recognizing module by a linker comprising Glycine Serine (GS) linker;
• and
• wherein the base excision repair inhibitor is a uracil DNA glycosylase inhibitor (Ugi) linked to the PmCDA1.

A nucleic acid-modifying enzyme complex wherein a nucleic acid sequence-recognizing module that specifically binds to a target nucleotide sequence in a given double-stranded DNA, a nucleic acid base converting enzyme and a base excision repair inhibitor are bonded, which complex converts one or more nucleotides in the targeted site to other one or more nucleotides or deletes one or more nucleotides, or inserts one or more nucleotides into said targeted site, without cleaving at least one strand of said double-stranded DNA in the targeted site, wherein the nucleic acid sequence-recognizing module is a CRISPR-Cas system wherein at least one DNA cleavage ability of Cas is inactivated,

• wherein said nucleic acid base converting enzyme is Petromyzon marinus cytosine deaminase 1 (PmCDA1);
• wherein the PmCDA1 has the amino acid sequence set forth in SEQ ID NO:
• 2,
• wherein the PmCDA1 is fused to the nucleic acid sequence-recognizing module by a linker comprising Glycine Serine (GS) linker;
• and
• wherein the base excision repair inhibitor is a uracil DNA glycosylase inhibitor (Ugi) linked to the PmCDA1.