Golubovskaia V M, Aprelikova O N, Tomilin N V
Mol Gen Mikrobiol Virusol. 1989 Jul(7):24-9.
Correction of heteroduplex DNA obtained by hybridization of uracil-containing single-stranded M13mp18 phage DNA and "mutant" synthetic oligonucleotide with deletion of cytosine in SalGI site was studied in ung+ and ung- E. coli strains. Uracil-containing DNA was prepared after growth of phage in an E. coli strain dut- ung-. The DNA was hybridized with "mutant" oligonucleotide then complementary DNA chain was synthesized by T4 DNA polymerase. Ung+ and ung- E. coli cells were transformed by DNA. In all experiments mutation frequency in ung+ was higher than in ung- cells (approximately 6-fold) and reached 11-50%. Absolute number of mutants was higher in ung+ cells. The results indicate that high level of mutagenesis depends on uracil repair system polarizing the correction of heteroduplex DNA.
在ung+和ung-大肠杆菌菌株中研究了通过含尿嘧啶的单链M13mp18噬菌体DNA与在SalGI位点缺失胞嘧啶的“突变型”合成寡核苷酸杂交获得的异源双链DNA的校正情况。含尿嘧啶的DNA是在噬菌体在大肠杆菌菌株dut- ung-中生长后制备的。将该DNA与“突变型”寡核苷酸杂交，然后用T4 DNA聚合酶合成互补DNA链。用该DNA转化ung+和ung-大肠杆菌细胞。在所有实验中，ung+中的突变频率高于ung-细胞（约6倍），达到11 - 50%。ung+细胞中突变体的绝对数量更高。结果表明，高水平的诱变取决于使异源双链DNA校正极化的尿嘧啶修复系统。
