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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several studies have shown that in vertebrate mtDNAs the nucleotide content at fourfold degenerate sites is well correlated with the site's time of exposure to the single-strand state, as predicted from the asymmetrical model of mtDNA replication. Here we examine whether the same explanation may hold for the regional variation in nucleotide content in the maternal and paternal mtDNAs of the mussel Mytilus galloprovincialis. The origin of replication of the heavy strand (O(H)) of these genomes has been previously established. A systematic search of the two genomes for sequences that are likely to act as the origin of replication of the light strand (O(L)) suggested that the most probable site lies within the ND3 gene. By adopting this O(L) position we calculated times of exposure for 0(FD) (nondegenerate), 2(FD) (twofold degenerate), and 4(FD) (fourfold degenerate) sites of the protein-coding part of the genome and for the rRNA, tRNA and noncoding parts. The presence of thymine and absence of guanine at 4(FD) sites was highly correlated with the presumed time of exposure. Such an effect was not found for the 2(FD) sites, the rRNA, the tRNA, or the noncoding parts. There was a trend for a small increase in cytosine at 0(FD) sites with exposure time, which is explicable as the result of biased usage of 4(FD) codons. The same analysis was applied to a recently sequenced mitochondrial genome of Mytilus trossulus and produced similar results. These results are consistent with the asymmetrical model of replication and suggest that guanine oxidation due to single-strand exposure is the main cause of regional variation of nucleotide content in Mytilus mitochondrial genomes.
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PMID:Nucleotide content gradients in maternally and paternally inherited mitochondrial genomes of the mussel Mytilus. 1763 81

Paraplagusia japonica (Cynoglossidae, Soleoidei) is characterized by a bilaterally asymmetrical and a series of fringes on the lips on the ocular side. Here we report for the first time the mitogenome of this tongue sole, which is 16,694 bp in length, and the gene order has been reorganized. The tRNA-Gln gene translocated from the light strand (L-strand) to the heavy strand (H-strand), accompanied by tRNA-Ile gene shuffling. In addition, the putative control region translocated downstream to the place between the ND1 and the tRNA-Gln genes, leaving a 26-bp trace fragment in the original position. Nevertheless, the rest gene order is identical to that of the typical fish. In addition, it is the first report of the rare ATT as an initiation codon for ND3, and the ATP6 (- 26) and ND5 (+26) are unusually shorter or longer than those in other flatfish. These data will provide useful information for better understanding the molecular mechanisms of gene reorganization in fish mitogenome.
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PMID:Control region translocation and a tRNA gene inversion in the mitogenome of Paraplagusia japonica (Pleuronectiformes: Cynoglossidae). 2354 89