Skip to main content
. 2018 Jun 20;164(3):183–193. doi: 10.1093/jb/mvy058

Fig. 1.

Fig. 1

Staining image and genetic map of human mtDNA. (A) Fluorescent microscopic images of mtDNA (small green dots) (top) and mitochondria (red tubes) (middle) of culture human cells. The merged image is shown (bottom). (B) Schematic presentation of human mtDNA. Gene coding regions for proteins, ribosomal RNAs (rRNAs) and transfer RNAs (tRNAs) are shown as blue, orange and red thick lines, respectively. Encoded proteins are ND1, 2, 3, 4, 4L, 5 and 6 subunits of NADH-ubiquinone oxidoreductase (Complex I); cytochrome b (cyt b), a subunit of ubiquinone-cytochrome c oxidoreductase (Complex III); COXI, II and III, subunits of cytochrome c oxidase (Complex IV); A6 and 8, subunits of ATP synthase (Complex V). The 12S rRNA and 16S rRNA are mitochondrial rRNA genes. Mitochondrial tRNA genes are shown by their cognate amino acids with single letter notation. The position of the major noncoding region (NCR) is shown as black lines between tRNAPhe and tRNAPro genes. Transcription from the light (L)-strand promoter (LSP) is responsible for ND6 mRNA and 8 tRNAs. While transcription from the heavy (H)-strand promoter 1 (HSP1) generates 2 rRNAs and 2 tRNAs and terminates at the 3′ end of the 16S rRNA gene, transcription from HSP2 produces almost the entirety of the H-strand transcripts. OH and OL are the major replication initiation sites of H- and L-strands, respectively, under strand-asynchronous mtDNA replication models. The approximate position of OH on mtDNA is shown as an orange oval, representing the unidirectionality of this origin. Ori-b is an initiation region that appears to function as the second initiation site for unidirectional asynchronous synthesis of the H-strand and as a bidirectional initiation origin. The approximate position of Ori-b is shown as an orange/blue oval representing the uni- and bidirectionality of this origin. Conserved sequence block II (CSB II) is shown as a pale-grey rectangle. The position of 7S DNA is shown as a grey bar outside mtDNA. Approximate distances between LSP and CSB II, CSB II and OH and OH and Ori-b in human mtDNA are shown with grey italic numbers.