Heterogeneity of minicircles in kinetoplast DNA of Leishmania tarentolae

Sharon S. Challberg, Paul T. Englund

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Kinetoplast DNA, the mitochondrial DNA in trypanosomatids, consists of thousands of DNA circles which are joined in a network. Leishmania tarentolae networks contain 10,000 covalently-closed minicircles, each about 840 base-pairs in length, and less than 50 maxicircles, each about 30,000 base-pairs in length. Minicircles in kinetoplast DNA networks from many species are heterogeneous in nucleotide sequence, and in this paper we describe our studies on L. tarentolae minicircle heterogeneity. Using restriction enzyme analyses we have found that there are three major minicircle sequence classes in this species. Class I minicircles comprise 70% of the total, class II comprise 15%, and class III comprise 7%. The remainder of the minicircles are in minor sequence classes. We have isolated full-length linear restriction fragments from the three major classes and have analyzed the relationship of class I and class II sequences. Each of these two classes contains a population of molecules which appears to be homogeneous based on restriction enzyme mapping, kinetics of reassociation, and thermal chromatography of the reannealed molecules. Similarities in the restriction maps of class I and class II minicircles suggested that they may have related sequences, and we have confirmed this homology by hybridization studies. Thermal chromatography of the heteroduplexes formed between class I and class II minicircles indicates that they differ in about 10 to 15% of their sequences.

Original languageEnglish (US)
Pages (from-to)447-472
Number of pages26
JournalJournal of molecular biology
Issue number3
StatePublished - Apr 15 1980

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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