Folate-sensitive fragile sites in Chinese hamster cell lines.

The expression of fragile sites in three different Chinese hamster cell lines was studied. Results showed that folate-sensitive fragile sites were expressed in the pericentromeric regions of chromosomes 1, 3, 4, 6, and 7 and in band 1q22. A comparison of the breakpoints involved in formation of chromosome rearrangements in some established Chinese hamster cell lines was also made. Results showed that while the specific type of rearrangement was random, the breakpoints were not. Three of the chromosomal sites most frequently involved in breaks were regions in which fragile sites were expressed.