Two extended arrays of a satellite DNA sequence at the centromere and at the short-arm telomere of Chinese hamster chromosome 5

We have cloned a Chinese hamster chromosome-specific repeated sequence (Sat CH5). This satellite is composed of a 33-bp unit organized in two extended tandem arrays. It is localized at the centromere and at the short-arm subte lomere of chromosome 5. Altogether, SatCH5 covers about 1-2 Mb per diploid genome and is not present in other species, including the Syrian hamster an d mouse. Since it is known in the Chinese hamster and numerous other verteb rate species that telomeric (TTAGGG)(n) repeats are localized at the centro meres of several chromosomes, we studied the localization of SatCH5 relativ e to (TTAGGG)(n) sequences. Using two-color fluorescence in situ hybridizat ion on stretched chromosomes and on DNA fibers, we have shown that at the c entromere of chromosome 5 SatCH5 and the (TTAGGG)(n) arrays are contiguous. SatCH5 is the first chromosome-specific repetitive sequence located at bot h the pericentromeric and subtelomeric regions of the same chromosome.