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Investigation of the mutagenic specificity of x‐rays using a retroviral shuttle vector in cho cells
Author(s) -
Skandalis A.,
Grosovsky A. J.,
Drobetsky E. A.,
Glickman B. W.
Publication year - 1992
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850200405
Subject(s) - shuttle vector , chinese hamster ovary cell , point mutation , biology , genetics , mutant , mutation , microbiology and biotechnology , vector (molecular biology) , gene , cell culture , recombinant dna
In some biological systems ionizing radiation appears to induce large deletions and rearrangements, while in others point mutations predominate the mutational spectrum. Moreover, while the point mutations are often randomly distributed, some systems exhibit “hot spots.” Retroviral shuttle vectors are particularly useful for investigating the basis of these differences since the genetic target can be conveniently analyzed in a variety of host backgrounds and genomic locations. We have studied the mutational specificity of X‐rays in a Chinese hamster ovary cell line (CHO) containing a stably integrated retroviral shuttle vector, carrying the CHO aprt cDNA as the genetic target. Cells were irradiated with 7 Gy using a 180 kVp X‐ray source. The predominant mutation (87% of all APRT mutants), as determined by Southern analysis, was the complete deletion of the shuttle vector construct. In addition, 23 APRT mutants, carrying an apparently intact shuttle vector, were characterized at the sequence level: 5 were transitions, 9 were transversions, 3 were small deletions or insertions, 4 were frameshifts, and 2 were small rearrangements. Although the type and the location of the point mutations character ized appeared largely random, small deletions, insertions, and frameshifts were frequently associated with direct sequence repeats. © 1992 Wiley‐Liss, Inc.