Single-strand interactions of mouse satellite DNA

Interactions of the complementary strands of mouse satellite DNA were investigated in the presence of polyribonucleotides, at high ionic strengths, and at different molar ratios of the two strands. Polyribonucleotide binding demonstrated the presence of T-rich and (A,C)-rich or C-rich sequences on the heavy strand. Ribopolymers bound to one strand of mouse satellite DNA were displaced by addition of the complementary DNA strand. However, the formation of mouse satellite DNA · DNA hybrids is essentially irreversible. High ionic strengths and formaldehyde were used to investigate the two steps, nucleation and rewinding, which comprise the reassociation of mouse satellite DNA. Compared with procaryotic DNA's, the complementary strands of mouse satellite DNA nucleate rapidly. The rewinding of nucleated complementary strands of mouse satellite DNA is inhibited at high ionic strengths and low temperatures. The effects of rapid nucleation of mismatched strands on the reassociation of animal satellite DNA's are discussed.