This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kasid, U. N. Articles by Dritschilo, A. Search for Related Content PubMed PubMed Citation Articles by Kasid, U. N. Articles by Dritschilo, A.

Sensitivities of NIH/3T3-derived Clonal Cell Lines to Ionizing Radiation: Significance for Gene Transfer Studies¹

Department of Radiation Medicine, Georgetown University School of Medicine, Vincent T. Lombardi Comprehensive Cancer Research Center, Washington, DC 20007 [U. N. K., T. B., A. D.]; Michael Reese Hospital, University of Chicago Center for Radiation Therapy, Pritzker School of Medicine, University of Chicago, Chicago, Illinois 60637 [R. R. W.]; and Department of Molecular Biology, Merck, Sharp and Dohme Research Laboratories, Rahway, New Jersey 07065 [G. E. M.]

Rodent cells are frequently used as recipients in experiments involving gene transfer, isolation, and characterization. The present studies were designed to investigate the clonal responses to ionizing radiation of NIH/3T3 cells subjected to DNA-mediated gene transfer. Radiation sensitivity (D₀) values were determined for the parental NIH/3T3 cell strain, six clonal cell lines transfected with DNA from radiation-resistant human tumor cells, and six nontransfected clonal cell lines. The radiation sensitivities of four transfected and two nontransfected clonal cell lines differed significantly from parental NIH/3T3 cells (P < 0.05). Detailed karyotype analysis of two nontransfected clonal cell lines with differing radiation sensitivities showed variation in chromosomal composition. Specifically, a minute chromosome was observed to segregate consistently (in 49 of 50 metaphases) with the genome of one NIH/3T3 clone (D₀ 2.07 Gy) and was completely absent (from 50 metaphases) in another NIH/3T3 clone (D₀ 1.06 Gy). In the parental NIH/3T3 strain (D₀ 2.02 Gy) 10% of cells (3 of 30 metaphases) had such minute chromosomes. These findings demonstrate that the clonal cellular heterogeneity of NIH/3T3 cells is characterized by genotypic and phenotypic variations which must be considered in the experimental design involving gene transfer and expression.

¹ This work was supported by grants from the NIH to A. D., R. R. W., and U. N. K.

² To whom requests for reprints should be addressed.

Received 11/16/88. Revised 3/13/89. Accepted 3/20/89.