SATELLITE-I DNA IN TRANSFORMED RAT-CELLS

P93-50, a 93-basepair (bp) repetitive DNA sequence from rats, was hybr idized to transformed sublines of rot endothelial origin. The sequence hybridized at or near the centromeres of most but not all chromosomes in two transformed cell lines and three single-cell derived cultures. The hybridization signal was also frequently present at the telomeres . These cell lines have a highly aberrant karyotype including dicentri c and multicentric chromosomes; however, even though this sequence lab eled the centromere regions of some chromosomes, it did nor hybridize with the telomere regions of the cell line XC, which rarely shows any dicentrics. Apparently, the telomere signals represent prematurely sep arating, inactive, terminal centromeres. The p93-50 sequence does nor influence the timing of centromere separation, nor it is necessary for formation of heterochromatin.