caa a22 4500 465820549 CHVBK 20180323112134.0 cr unu---uuuuu 170327e19900501xx s 000 0 eng 10.1007/BF01233356 doi (NATIONALLICENCE)springer-10.1007/BF01233356 Murnane John Laboratory of Radiobiology and Environmental Health, University of California, 94143, San Francisco, California aut Influence of cellular sequences on instability of plasmid integration sites in human cells [Elektronische Daten] [John Murnane] To learn more about mechanisms of genome instability in human cells, I investigated DNA sequences that promote high rates of recombination by analyzing rare unstable plasmid integration sites in simian virus 40-transformed human fibroblasts. Previous studies had hypothesized that rearrangement or loss of integrated sequences could be attributed to adjacent cellular DNA. Consistent with this interpretation, a cloned fragment containing both the integrated plasmid and 2.0 kb of adjacent cell DNA from one such unstable integration site in the cell line LM205 demonstrated a much higher incidence of rearrangements when integrated into other chromosome locations than did the original plasmid. To further test this hypothesis, portions of cellular DNA from this region were integrated in duplicate in other locations to determine their ability to promote restriction-fragment-length polymorphism, an indicator of high rates of homologous recombination. Although two types of instability were observed, neither could be attributed solely to the cell sequences being tested in the plasmid. The first type of instability was a transient deletion or amplification of the plasmid DNA soon after integration, which appeared to be a general phenomenon often associated with any type of newly integrated sequence. A second type of instability continued indefinitely for many cell generations, as did that observed in cell line LM205. Because this was rare (one of 78 clones tested), it could not be attributed solely to cell sequences contained within the plasmid. However, the rearrangements in this cell clone occurred exclusively within the cell DNA adjacent to the integration site, again suggesting a role forcis-acting cell sequences in this process. The inability to identify specific cell sequences responsible for instability may therefore indicate that a complex combination of sequences is involved, possibly within both the plasmid and cell DNA. Plenum Publishing Corporation, 1990 Somatic Cell and Molecular Genetics Kluwer Academic Publishers-Plenum Publishers 16/3(1990-05-01), 195-209 0740-7750 16:3<195 1990 16 11188 https://doi.org/10.1007/BF01233356 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01233356 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Murnane John Laboratory of Radiobiology and Environmental Health, University of California, 94143, San Francisco, California aut NATIONALLICENCE 773 0- Somatic Cell and Molecular Genetics Kluwer Academic Publishers-Plenum Publishers 16/3(1990-05-01), 195-209 0740-7750 16:3<195 1990 16 11188 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer