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Chromosomal radiosensitivity at intrachromosomal telomeric sites
Author(s) -
Alvarez Luis,
Evans James W.,
Wilks Rebecah,
Lucas Joe N.,
Brown J. Martin,
Giaccia Amato J.
Publication year - 1993
Publication title -
genes, chromosomes and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.754
H-Index - 119
eISSN - 1098-2264
pISSN - 1045-2257
DOI - 10.1002/gcc.2870080103
Subject(s) - chinese hamster ovary cell , biology , telomere , radiosensitivity , metaphase , microbiology and biotechnology , chromosome , fluorescence in situ hybridization , karyotype , cell culture , genome , dna , genetics , gene , irradiation , physics , nuclear physics
Abstract Telomeric DNA is composed of highly conserved sequences which are present at the termini of chromosomes as well as at intrachromosomal locations. Here, we studied a Chinese hamster ovary (CHO) cell line, BL‐10, with highly stable amplified telomeric DNA at the termini as well as at intrachromosomal locations. We show that intrachromosomal or interstitial telomeric sites in this cell line and in another CHO cell line, HA‐1, are radiosensitive in that they are more prone to breakage than would be expected based on the percentage of the genome composed of telomeric sequences. The frequency of breakage at interstitial telomeric sites is 4.3 to 8.3 times higher than that in the CHO genome overall. These conclusions are reached by both conventional cytogenetic analysis of two CHO cell lines which have the same survival rates after exposure to ionizing radiation, and by use of double fluorescence in situ hybridization (FISH) with a pan‐telomere‐specific probe and a CHO chromosome‐specific library in the same metaphase cells after irradiation. © 1993 Wiley‐Liss, Inc.