Elongation of displacement-loop strands in human and mouse mitochondrial DNA is arrested near specific template sequences.

Abstract

Animal mitochondrial DNA (mtDNA) maintains a displacement loop (D loop) at the heavy strand origin of replication. These D loops represent sharply limited synthesis ofheavy strands and provide a unique opportunity to examine the termination of DNA synthesis. Direct sizing at the nucleotide level indicates that the 3' ends of D-loop strands of human and mouse mtDNA are discrete and map within three to five nucleotides on the complementary template strand. In the case of human mtDNA, there is a single trinucleotide stop point 51-53 nucleotides downstream from a 15-nucleotide template sequence

Comparison of evolutionary rates in the mitochondrial DNA cytochrome b gene and control region and their implications for phylogeny of the Cobitoidea (Teleostei: Cypriniformes)

“…Saunders and Edwards (2000) studied dynamics and phylogenetic implications of mtDNA CR sequences in the New World Jays and found a slow rate of evolution in the CR. They suggested that their data indicated a higher Studies have showed that CR contains sequences related to termination of H-strand replication, the origin of H-strand, and promoters of transcription to both L-and H-strand (Doda et al, 1981;Randi and Lucchini, 1998;Saccone et al, 1991;Sbisà et al, 1997;Southern et al, 1988). This indicates that the CR has evolutionary constraints.…”

Mitochondrial involvement in neurodegenerative diseases

“…The relevance of DSBs in deletion generation was demonstrated in a mouse model, where strand breaks were induced by expression of a mitochondrially targeted endonuclease (71). In this model system, many of the deletions had a breakpoint within the D-loop region of the mitochondrial genome, close to the replication-relevant termination associated sequence (72).…”

Structure and genetic variation of the mitochondrial control region in the honey bee Apis mellifera

“…This sequence is read on the complementary strand (Clary and Wolstenholme 1987), and with a few nucleotide changes, it is the one highlighted in the pink box of Figure 1 and the grey box in Figure 2a. Interestingly, within this structure, there is an almost exact match of a stop signal described in humans and mice by Doda et al (1981) which has the motif 5′-ACAT TAAAYYAAT-3′ and is present on A. mellifera c o m p l e m e n t a r y s t r a n d a s 5 ′ -AT AT TA AAATAAT-3′ (bold letters denote mutated nucleotides, see sequence underlined in CB1 of Figure 1 and also Figure 2a). This sequence, highlighted in pink in Figure 2, is conserved in all individuals analyzed but never forms a single stem and loop structure contrary to the Apis model proposed by Zhang et al (1995, see their Figure 4c) unless at a high energetic cost.…”