Patent ID: 7223589

Claim:
A microorganism belonging to the genus Escherichia , which is transformed with a gene encoding a ribonucleotide reductase and in which 2′-deoxyribonucleoside degradation activity is decreased or eliminated by disrupting a gene encoding a purine nucleoside phosphorylase on chromosomal DNA, and which has an ability to produce a 2′-deoxyribonucleoside; wherein the gene encoding a ribonucleotide reductase comprises a sequence which is amplified by PCR using oligonucleotides having sequences of SEQ ID NOs: 1 and 2 as primers and the chromosomal DNA of the bacterium as a template, and wherein the gene encoding a purine nucleoside phosphorylase comprises a sequence which is amplified by PCR using oligonucleotides having sequences of SEQ ID NOs: 3 and 4 as primers and the chromosomal DNA of the bacterium as a template.