Sequence analysis of lacZ- mutations induced by ion beam irradiation in double-stranded M13mp18DNA
- 25 Downloads
While M13mp18 double-stranded DNA was irradiated with ion beam, and transfected intoE. coli JM103, a decrease of transfecting activity was discovered. The lacZ- mutation frequency at 20% survival could reach (3.6–16.8) × 104, about 2, 3–10 times that of unirradiated M13DNA. Altogether, 27 IacZ-mutants were selected, 10 of which were used for sequencing. 7 of the sequenced mutants show base changes in 250-bp region examined (the remaining 3 mutants probably have base changes outside the regions sequenced). 5 of the base-changed mutants contain more than one mutational base sites (some of them even have 5–6 mutational base sites in 250-bp region examined); this dense distribution of base changes in polysites has seldom been seen in X-rays, Y-rays or UV induced DNA mutations. Our experiments also showed that the types of base changes include transitions(50%), transversions (45%) and deletion (5%); no addition or duplication was observed. The transitions were mainly C→T and A→G; the transversions were mainly C→A and C→G. The mutations involving cytosine residue (in the template strand) constitute about 60% of all the base changes observed. In comparison with the surrounding sequences of mutational base sites, the base located between TG and CT is found to be easily substituted.
Keywordsion beam irradiation M13DNA lacZ− mutation sequence analysis
Unable to display preview. Download preview PDF.
- 1.Yu, Z. L., Qiu, L. J., Huo, Y. P., Advances of breeding and biological effect research of ion beam irradiation,J. Anhui Agricultural College (in Chinese), 1991, 18:251.Google Scholar
- 2.Yu, Z. L., Wang, X. D., Wu, Y. J.et al., Studies for principle of mutation in rice induced by ion beam irradiation,J. Anhui Agricultural Sciences (in Chinese), 1989, 17(1): 12.Google Scholar
- 3.Wu, Y. J., Yu, Z. L., Dong, J. G.et al., Effect of mutation in rice induced by ion beam irradiation,J. Anhui Agricultural Sciences (in Chinese), 1989, 17(2): 10.Google Scholar
- 4.Li, L., Yang, J. B., Li, J.et al., Research for structure and functibn of pUC18 DNA irradiated by ion beam,J. Anhui Agricultural Sciences (in Chinese), 1994, 22(4):288.Google Scholar
- 5.Sambrook, J., Fritsch, E. J., Maniatis, T.,Molecular Cloning—A Laboratory Manual, New York:Cold Spring Harbor Laboratory Press, 1989.Google Scholar
- 13.Yu, Z. L., Shao, C. L., Dose-effect of the tyrosine sample implanted by a low energe N+ ion beam,Radiat. Phys. Chem., 1994, 30:145.Google Scholar