In D-loop: 40 years of mitochondrial 7S DNA.
Given the tiny size of the mammalian mitochondrial genome, at only 16.5 kb, it is often surprising how little we know about some of its molecular features, and the molecular mechanisms governing its maintenance. One such conundrum is the biogenesis and function of the mitochondrial displacement loop (D-loop). The mitochondrial D-loop is a triple-stranded region found in the major non-coding region (NCR) of many mitochondrial genomes, and is formed by stable incorporation of a third, short DNA strand known as 7S DNA. In this article we review the current affairs regarding the main features of the D-loop structure, the diverse frequency of D-loops in the mtDNAs of various species and tissues, and also the mechanisms of its synthesis and turnover. This is followed by an account of the possible functions of the mitochondrial D-loop that have been proposed over the last four decades. In the last section, we discuss the potential links of the D-loop with mammalian ageing.
MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, United Kingdom. Electronic address: Thomas.Nicholls@mrc-mbu.cam.ac.uk.
Thomas J
TJ
Nicholls
MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, United Kingdom. Electronic address: Michal.Minczuk@mrc-mbu.cam.ac.uk.
Michal
M
Minczuk
D000367:Age Factors; D000375:Aging / Q000235:genetics / Q000378:metabolism; D000818:Animals; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D013329:Structure-Activity Relationship
D004272:DNA, Mitochondrial
7S DNA; D-loop; Mitochondria; Mitochondrial control region; Mitochondrial non-coding region; mtDNA; mtDNA replication