title: DNA-relaxing activity and endonuclease activity in Xenopus laevis oocytes.
abstract: Complex simian virus 40 DNA produced by a soluble cell-free extract derived from stage 6 oocytes of Xenopus laevis consists of fully relaxed circles (i.e., with no superhelical turns). An endonuclease and a DNA-relaxing protein, either or both of which could be responsible for the relaxation of the complex DNA, have been purified from the extract. The endonuclease(s) produces nicked circles (having a single-strand scission) and linear full-size molecules. The DNA-relaxing protein is in the nucleus, has a molecular weight of apporximately 70,000, and is able to remove both negative and positive superhelical turns.
mesh_terms: D000818:Animals; D002474:Cell-Free System; D004247:DNA / Q000378:metabolism; D004270:DNA, Circular / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism*; D005260:Female; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D009865:Oocytes / Q000201:enzymology*; D010063:Ovum / Q000201:enzymology*; D013539:Simian virus 40; D014981:Xenopus
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral; D004247:DNA; D004720:Endonucleases