Dissociation of minor satellite from the centromere in mouse.

The minor satellite DNA of mouse is believed to constitute the centromere. We report that centromeres of some chromosomes in the Cl1D cells of mouse are not associated with this DNA even though the latter is present on these chromosomes. The satellite DNA was detected distally from the centromere and could not be mistaken as a component of the centromere. We also report that the site of the primary constriction may not always coincide with the site of the anti-kinetochore antibody reaction. Whereas the regions containing the major satellite decondense upon treatment with bisbenzimidazole (Hoechst 33258), the sites carrying minor satellite resist decondensing.