Analysis of the α‐Satellite DNA from African Green Monkey Cells by Restriction Nucleases

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Abstract
By the use of restriction endonucleases the organization of .alpha.-satellite DNA from African green monkeys cells (Cercopithecus aethiops) was analzyed. With endo R .times.. HindIII, endo R .cntdot. AluI and endo R .cntdot. EcoRI at conditions of low salt and high pH (endo R .cntdot. EcoRI*) all of the satellite was digested while only a part of the satellite was cleaved with endo R .cntdot. Bsu and endo R .cntdot. EcoRI under standard conditions. With each of the 4 nucleases a series of fragments was formed which were multiples in size of a basic repeat unit linked in tandem arrays in the intact satellite. The quantitative evaluation of the digestion with each nuclease as well as with combinations of 2 nucleases yielded information about the distribution of the cleavage sites. While the arrangement of the endo R .cntdot. HindIII cleavage sites conforms to a random distribution across the entire satellite, the results from the endo R .cntdot. Bsu and endo R .cntdot. EcoRI cleavage patterns are consistent with a picture where the cleavage sites are clustered in fractions of the satellite. Since endo R .cntdot. AluI recognizes the central 4 nucleotide pairs of the endo R .cntdot. HindIII cleavage site, the redigestion of the endo R .cntdot. HindIII dimer with endo R .cntdot. AluI gave information about the distribution of mutations in the satellite. The results together with the comparison of the sequence divergence determined from digestion with endo R .cntdot. HindIII and endo R .cntdot. EcoRI*, lend support to the hypothesis that mutations have affected all bases in the satellite evenly. The .gamma.-satellite, another fraction of the African green monkey DNA, could be separated by Ag+/CsSO4 density gradient centrifugation into 2 components. Using the 3 restriction nucleases, both components gave a background of fragments of heterogenous length on gel electrophoresis with some faint bands of no apparent regularity in 1 case.