| Abstract: | Component alpha DNA is a highly repetitive sequence that comprises nearly a quarter of the African green monkey (Cercopithecus aethiops) genome. A previous microbial restriction enzyme analysis showed that the repeat structure of component alpha DNA is based upon a monomeric unit of 176 +/- 4 base-pairs. An endonuclease, provisionally termed Case I, has been isolated from African green monkey testes that cleaves component alpha DNA into multimeric segments based upon the same repeat periodicity as that revealed by microbial restriction enzymes. The primary sites of Cae I cleavage in the component alpha sequence appear to be 120 +/- 6 base-pairs distant from the Hind III sites and 73 +/- 6 base-pairs distant from the Eco RI* sites. Cae I has been partially characterized with special reference to the effects of ATP and S-adenosylmethionine on the cleavage of component alpha DNA. Cae I may be a member of a class of similar site-specific nucleases present in mammalian cells. Cae I also cleaves mouse satellite DNA into a multimeric series of discrete segments: the periodicity of this series is shorter than that revealed by Eco RII retriction analysis of mouse satellite DNA. |
