Human heart mitochondrial DNA is organized in complex catenated networks containing abundant four-way junctions and replication forks.

ABSTRACT: Analysis of human heart mitochondrial DNA (mtDNA) by electron microscopy and agarose gel electrophoresis revealed a complete absence of the -type replication intermediates seen abundantly in mtDNA from all other tissues. Instead only Y- and X-junctional forms were detected after restriction digestion. Uncut heart mtDNA was organized in tangled complexes of up to 20 or more genome equivalents, which could be resolved to genomic monomers, dimers, and linear fragments by treatment with the decatenating enzyme topoisomerase IV plus the cruciform-cutting T7 endonuclease I. Human and mouse brain also contained a population of such mtDNA forms, which were absent, however, from mouse, rabbit, or pig heart. Overexpression in transgenic mice of two proteins involved in mtDNA replication, namely huma

SUBMITTER: Pohjoismaki JL 

PROVIDER: S-EPMC2755869 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature