Yenofsky R L, Fine M, Pellow J W
Phytogen, Pasadena, CA 91105.
Proc Natl Acad Sci U S A. 1990 May;87(9):3435-9. doi: 10.1073/pnas.87.9.3435.
The neo (neomycin-resistance) gene of transposon Tn5 encodes the enzyme neomycin phosphotransferase II (EC 2.7.1.95), which confers resistance to various aminoglycoside antibiotics, including kanamycin and G418. The gene is widely used as a selectable marker in the transformation of organisms as diverse as bacteria, yeast, plants, and animals. We found a mutation that involves a glutamic to aspartic acid conversion at residue 182 in the protein encoded by the chimeric neomycin phosphotransferase II genes of several commonly used transformation vectors. The mutation substantially reduces phosphotransferase activity but does not appear to affect the stability of the neomycin phosphotransferase II mRNA or protein. Plants and bacteria transformed with the mutant gene are less resistant to antibiotics than those transformed with the normal gene. A simple restriction endonuclease digestion distinguishes between the mutant and the normal gene.
转座子Tn5的新霉素（新霉素抗性）基因编码新霉素磷酸转移酶II（EC 2.7.1.95），该酶赋予对包括卡那霉素和G418在内的多种氨基糖苷类抗生素的抗性。该基因在细菌、酵母、植物和动物等多种生物体的转化中被广泛用作选择标记。我们在几种常用转化载体的嵌合新霉素磷酸转移酶II基因编码的蛋白质中发现了一个突变，该突变涉及第182位残基处谷氨酸向天冬氨酸的转化。该突变显著降低了磷酸转移酶活性，但似乎不影响新霉素磷酸转移酶II mRNA或蛋白质的稳定性。用突变基因转化的植物和细菌比用正常基因转化的植物和细菌对抗生素的抗性更低。一种简单的限制性内切酶消化可区分突变基因和正常基因。
