Liver DNA Fragmentation Research Articles

Fragmentation and reassociation of nuclear rat liver DNA

Summary Isolated nuclear rat liver DNA was fragmented either by sonication or by acid DNAase (EC 3.1.4.6) treatment in order to obtain fragments of DNA about 500 nucleotides in length. Physico-chemical properties of the obtained DNA fragments, S20,w, Tm, base composition, resistance toward nuclease S1 action and reassociations were studied and the characteristics of the reassociated DNA-DNA duplexes were analyzed. The two types of DNA fragments had different reassociation curves. The differences seem to be due to changes in base composition and to the presence of nicks on fragments obtained by acid DNAase treatment. The DNA-DNA duplexes obtained either by sonication or by enzymatic hydrolysis have however similar physical properties.