Horiuchi T, Maki H, Sekiguchi M
Mol Gen Genet. 1978 Jul 25;163(3):277-83. doi: 10.1007/BF00271956.
A conditional lethal mutator, dnaQ49, was found in Escherichia coli K12. The dnaQ49 mutation caused stimulation of rifampicin-, nalidixic acid- and streptomycin-resistant mutation frequencies 100 to 2000 fold at 30 degrees C and the frequencies were further increased 50 to 100 fold at 35 degrees C or higher temperatures. Cells carrying dnaQ49 were unable to grow in salt-free L-broth at 44.5 degrees C, and DNA synthesis but not protein synthesis of the cells was suppressed under the restrictive conditions. The dnaQ gene was located at about 5 min on the E. coli linkage map and the order of the genes residing in this region was determined to be ton A-dnaE-metD-dnaQ-pro A.
在大肠杆菌K12中发现了一种条件致死突变体dnaQ49。dnaQ49突变在30℃时使对利福平、萘啶酸和链霉素的抗性突变频率提高了100至2000倍，在35℃或更高温度下频率进一步提高了50至100倍。携带dnaQ49的细胞在44.5℃的无盐L肉汤中无法生长，在限制条件下细胞的DNA合成而非蛋白质合成受到抑制。dnaQ基因位于大肠杆菌连锁图谱上约5分钟处，该区域内基因的顺序确定为tonA-dnaE-metD-dnaQ-proA。
