Developmental and pathological changes in the human cardiac muscle mitochondrial DNA organization, replication and copy number.
Adult human heart mitochondrial DNA (mtDNA) has recently been shown to have a complex organization with abundant dimeric molecules, branched structures and four-way junctions. In order to understand the physiological significance of the heart-specific mtDNA maintenance mode and to find conditions that modify human heart mtDNA structure and replication, we analyzed healthy human heart of various ages as well as several different heart diseases, including ischemic heart disease, dilated as well as hypertrophic cardiomyopathies, and several mitochondrial disorders. By using one- and two-dimensional agarose gel electrophoresis, various enzymatic treatments and quantitative PCR we found that in human newborns heart mtDNA has a simple organization, lacking junctional forms and dimers. The adult-type branched forms are acquired in the early childhood, correlating with an increase in mtDNA copy number. Mitochondrial disorders involving either mutations in the mtDNA polymerase gamma (PolGalpha) or mtDNA helicase Twinkle, while having no obvious cardiac manifestation, show distinct mtDNA maintenance phenotypes, which are not seen in various types of diseased heart or in mitochondrial disorders caused by point mutations or large-scale deletions of mtDNA. The findings suggest a link between cardiac muscle development, mtDNA copy number, replication mode and topological organization. Additionally, we show that Twinkle might have a direct role in the maintenance of four-way junctions in human heart mtDNA.
Pohjoismäki
Jaakko L O
JL
Department of Forensic Medicine, Medical School, University of Tampere, Tampere, Finland. Jaakko.Pohjoismaki@uta.fi
Goffart
Steffi
S
Taylor
Robert W
RW
Turnbull
Douglas M
DM
Suomalainen
Anu
A
Jacobs
Howard T
HT
Karhunen
Pekka J
PJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D056915:DNA Copy Number Variations / Q000235:genetics*; D004265:DNA Helicases / Q000235:genetics; D004256:DNA Polymerase I / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006331:Heart Diseases / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D051379:Mice; D008875:Middle Aged; D028361:Mitochondrial Diseases / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics; D024101:Mitochondrial Proteins; D009154:Mutation / Q000235:genetics; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology*; D011995:Recombination, Genetic / Q000235:genetics
D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D004256:DNA Polymerase I; D004265:DNA Helicases; C431576:TWNK protein, human
Hum Mutat. 2008 Sep;29(9):E150-72
18546365
Nucleic Acids Res. 2003 Jun 1;31(11):e61
12771225
J Biol Chem. 2009 Aug 7;284(32):21446-57
19525233
Eur J Hum Genet. 2008 Oct;16(10):1265-74
18398437
J Mol Biol. 2010 Apr 16;397(5):1144-55
20184890
Ann Neurol. 2002 Aug;52(2):211-9
12210792
J Biol Chem. 2009 Jul 17;284(29):19501-10
19478085
Genome Res. 2000 Jan;10(1):5-16
10645945
J Mol Biol. 1981 May 5;148(1):77-93
7310869
Hum Mol Genet. 2008 Dec 1;17(23):3822-35
18775955
Nucleic Acids Res. 2007;35(19):6458-74
17884915
Proc Natl Acad Sci U S A. 2005 Dec 6;102(49):17687-92
16301523
EMBO J. 2006 Nov 15;25(22):5358-71
17066082
Ann Neurol. 2004 Apr;55(4):478-84
15048886
Neuropediatrics. 2008 Jun;39(3):179-83
18991199
J Mol Cell Cardiol. 2005 Jan;38(1):81-91
15623424
Nat Genet. 2008 Mar;40(3):275-9
18305478
Nat Genet. 2001 Jul;28(3):223-31
11431692
Biogerontology. 2009 Jun;10(3):235-52
19083132
Trends Biochem Sci. 2000 Apr;25(4):165-73
10754548
Circulation. 2005 Aug 2;112(5):683-90
16043643
Hum Mol Genet. 2009 Jan 15;18(2):328-40
18971204
Nucleic Acids Res. 2006;34(20):5815-28
17062618
Mech Ageing Dev. 2005 Nov;126(11):1192-200
16099018
Neuropathol Appl Neurobiol. 2009 Feb;35(1):120-4
19187065
Hum Mol Genet. 2005 Apr 1;14(7):893-902
15703189
Biochem J. 2009 Sep 25;423(2):157-68
19772495
EMBO J. 1996 Feb 1;15(3):684-93
8599952
Neurology. 1997 May;48(5):1244-53
9153451
Nucleic Acids Res. 2007;35(10):3238-51
17452351
Ann Neurol. 2005 Jun;57(6):921-3
15929042
Mol Cell Biol. 2007 Feb;27(3):1133-45
17116696
Nat Genet. 2002 Feb;30(2):145-6
11799391
Cardiovasc Res. 2004 Nov 1;64(2):198-207
15485678
Curr Genet. 2000 May;37(5):304-14
10853767
Nat Struct Mol Biol. 2010 Jan;17(1):11-6
20051983