De Vos G F, Finan T M, Signer E R, Walker G C
J Bacteriol. 1984 Jul;159(1):395-9. doi: 10.1128/jb.159.1.395-399.1984.
Transposon Tn5 encodes streptomycin resistance in addition to kanamycin-neomycin resistance. This resistance was not detectable in Escherichia coli but was efficiently expressed in Rhizobium meliloti and certain other strains. By analysis of cloned Tn5 restriction endonuclease fragments, the streptomycin resistance (str) gene was located in the right-hand side of the central region as the transposon is conventionally drawn. Transcription of str appeared to originate at pL, the promoter for the neo gene (neomycin phosphotransferase type II). Expression of streptomycin resistance in E. coli was obtained after cloning of the neo-str region downstream of a strong E. coli promoter. A construct in which PL was deleted also showed differential expression of streptomycin resistance.
转座子Tn5除了编码对卡那霉素-新霉素的抗性外，还编码对链霉素的抗性。这种抗性在大肠杆菌中无法检测到，但在苜蓿根瘤菌和某些其他菌株中能有效表达。通过对克隆的Tn5限制性内切酶片段进行分析，按照转座子的常规绘图方式，链霉素抗性（str）基因位于中央区域的右侧。str的转录似乎起始于neo基因（新霉素磷酸转移酶II型）的启动子pL。在将neo-str区域克隆到一个强大肠杆菌启动子下游后，在大肠杆菌中获得了链霉素抗性的表达。一个缺失了PL的构建体也显示出链霉素抗性的差异表达。
