Sequence of centromere separation. Minor satellite DNA does not influence separation of inactive centromeres in transformed cells of mouse

Neoplastic cells may carry inactive centromeres on some multicentric, yet stable, chromosomes. We report that some inactive centromeres in L929 mouse cells do not contain minor satellite DNA, the DNA fraction which has been suggested to constitute the centromere. We compared the sequence of separation of inactive centromeres carrying the minor satellite with those lacking this fraction. The sequence of separation appears to be independent of whether or not the inactive centromeres carry the minor satellite DNA. The timing of replication of the inactive centromeres is also independent of this DNA. Hence, minor satellite of mouse is not a factor in holding together the subunits of inactive centromeres. Extension of these results to active centromeres might suggest that the minor satellite DNA is not a factor responsible for adhesion of the two centromere sub-units up until late meta-anaphase.