{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T16:11:51Z","timestamp":1790698311905,"version":"4.1.0"},"reference-count":0,"publisher":"Rockefeller University Press","issue":"2","content-domain":{"domain":["rupress.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1978,2,1]]},"abstract":"<jats:p>We have used restriction endonucleases PstI, EcoRI, HapII, HhaI, and S1 nuclease to demonstrate the presence of a large complex component, the maxi-circle, in addition to the major mini-circle component in kinetoplast DNA (kDNA) networks of Trypanosoma brucei (East African Trypanosomiasis Research Organization [EATRO] 427). Endonuclease PstI and S1 nuclease cut the maxi-circle at a single site, allowing its isolation in a linear form with a mol wt of 12.2 x 10(6), determined by electron microscopy. The other enzymes give multiple maxi-circle fragments, whose added mol wt is 12-13 x 10(6), determined by gel electrophoresis. The maxi-circle in another T. brucei isolate (EATRO 1125) yields similar fragments but appears to contain a deletion of about 0.7 x 10(6) daltons. Electron microscopy of kDNA shows the presence of DNA considerably longer than the mini-circle contour length (0.3 micron) either in the network or as loops extending from the edge. This long DNA never exceeds the maxi-circle length (6.3 microns) and is completely removed by digestion with endonuclease PstI. 5-10% of the networks are doublets with up to 40 loops of DNA clustered between the two halves of the mini-circle network and probably represent a division stage of the kDNA. Digestion with PstI selectively removes these loops without markedly altering the mini-circle network. We conclude that the long DNA in both single and double networks represents maxi-circles and that long tandemly repeated oligomers of mini-circles are (virtually) absent. kDNA from Trypanosoma equiperdum, a trypanosome species incapable of synthesizing a fully functional mitochondrion, contains single and double networks of dimensions similar to those from T. brucei but without any DNA longer than mini-circle contour length. We conclude that the maxi-circle of trypanosomes is the genetic equivalent of the mitochondrial DNA (mtDNA) of other organisms.<\/jats:p>","DOI":"10.1083\/jcb.76.2.293","type":"journal-article","created":{"date-parts":[[2004,5,14]],"date-time":"2004-05-14T23:04:59Z","timestamp":1084575899000},"page":"293-309","update-policy":"https:\/\/doi.org\/10.1083\/jcb.crossmarkpolicy","source":"Crossref","is-referenced-by-count":95,"title":["Isolation and characterization of kinetoplast DNA from bloodstream form of Trypanosoma brucei."],"prefix":"10.1083","volume":"76","author":[{"given":"A H","family":"Fairlamb","sequence":"first","affiliation":[{"name":"Section for Medical Enzymology and Molecular Biology, University of Amsterdam, The Netherlands."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P O","family":"Weislogel","sequence":"additional","affiliation":[{"name":"Section for Medical Enzymology and Molecular Biology, University of Amsterdam, The Netherlands."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J H","family":"Hoeijmakers","sequence":"additional","affiliation":[{"name":"Section for Medical Enzymology and Molecular Biology, University of Amsterdam, The Netherlands."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P","family":"Borst","sequence":"additional","affiliation":[{"name":"Section for Medical Enzymology and Molecular Biology, University of Amsterdam, The Netherlands."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"291","published-online":{"date-parts":[[1978,2,1]]},"container-title":["The Journal of cell biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/rupress.org\/jcb\/article-pdf\/76\/2\/293\/1633883\/293.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/rupress.org\/jcb\/article-pdf\/76\/2\/293\/1633883\/293.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,7,24]],"date-time":"2023-07-24T08:10:57Z","timestamp":1690186257000},"score":1,"resource":{"primary":{"URL":"https:\/\/rupress.org\/jcb\/article\/76\/2\/293\/18915\/Isolation-and-characterization-of-kinetoplast-DNA"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1978,2,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1978,2,1]]}},"URL":"https:\/\/doi.org\/10.1083\/jcb.76.2.293","relation":{},"ISSN":["0021-9525","1540-8140"],"issn-type":[{"value":"0021-9525","type":"print"},{"value":"1540-8140","type":"electronic"}],"subject":[],"published":{"date-parts":[[1978,2,1]]}}}