Rood J I, Laird A J, Williams J W
Gene. 1980 Feb;8(3):255-65. doi: 10.1016/0378-1119(80)90003-7.
The dihydrofolate reductase structural gene, folA, has been closed into the multicopy vector pBR322 following the gene's enrichment by bacteriophage Mu-mediated transposition. Strains carrying the resultant plasmid, pJFM8, produce 25 to 30 times more dihydrofolate reductase than control strains. Consequently they are resistant to trimethoprim, an inhibitor of this enzyme. This elevation in enzyme production is due to an increase in the number of folA gene copies per cell. The higher yield of dihydrofolate reductase obtained will be extremely useful for purifying and characterising this trimethoprim-sensitive chromosomally derived enzyme. The plasmid will also be invaluable for studying the structure, function and regulation of dihydrofolate reductase.
在通过噬菌体Mu介导的转座对二氢叶酸还原酶结构基因folA进行富集之后，该基因已被克隆到多拷贝载体pBR322中。携带所得质粒pJFM8的菌株产生的二氢叶酸还原酶比对照菌株多25至30倍。因此，它们对三甲氧苄氨嘧啶具有抗性，三甲氧苄氨嘧啶是这种酶的一种抑制剂。酶产量的这种提高是由于每个细胞中folA基因拷贝数的增加。所获得的更高产量的二氢叶酸还原酶对于纯化和表征这种对三甲氧苄氨嘧啶敏感的染色体衍生酶将极为有用。该质粒对于研究二氢叶酸还原酶的结构、功能和调控也将具有极高的价值。
