CONSTRUCTION OF CHINESE-HAMSTER CHROMOSOME-SPECIFIC DNA LIBRARIES ANDTHEIR USE IN THE ANALYSIS OF SPONTANEOUS CHROMOSOME REARRANGEMENTS INDIFFERENT CELL-LINES

Chinese hamster (Cricetulus griseus) and a wide variety of cell lines derived from it have been extensively used for radiobiological and gen otoxicity studies. In this report, we describe the development of chro mosome-specific DNA libraries for Chinese hamster chromosomes 1, 2, 3, 5, 6, 7 and 8 by the linker/adaptor method. The specificity of these probes have been checked by FISH on primary embryonic fibroblast (CHE) metaphase chromosomes. The diploid number of chromosomes in different cell lines of CHO often varies from 19 to 21 and karyotyping is very difficult owing to many spontaneous rearrangements. Using Chinese hams ter chromosome-specific DNA libraries, we have analysed the spontaneou s chromosome rearrangements in three different Chinese hamster transfo rmed cell Lines, V79, CHO-KI and CHO-9. The results indicate that one of each of the first and fifth pair of chromosomes are involved in rec iprocal translocations in both CHO-9 and CHO-K1 cells. The hybridisati on patterns obtained with chromosome-specific probes 2, 3, 5, 6, 7 and 8 indicated rearrangements have occured involving terminal and inters titial translocations in V79, CHO-KI and CHO-9 cells.