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Cosegregation of novel mitochondrial 16S rRNA gene mutations with the age-associated T414G variant in human cybrids.

Seibel P, Di Nunno C, Kukat C, Schäfer I, Del Bo R, Bordoni A, Comi GP, Schön A, Capuano F, Latorre D, Villani G - Nucleic Acids Res. (2008)

Bottom Line: In the present work, we have analyzed the bioenergetic properties associated with the age-related T414G mutation of the mtDNA control region in transmitochondrial cybrids.The results show that the T414G mutation does not cause per se any detectable bioenergetic change.The results are discussed in the more general context of the complex heterogeneity and the dramatic instability of the mitochondrial genome during cell culture of transmitochondrial cybrids.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Cell Therapy, Center for Biotechnology and Biomedicine, Universität Leipzig, Deutscher Platz 5, 04103 Leipzig, Germany. peter.seibel@bbz.uni-leipzig.de

ABSTRACT
Ever increasing evidence has been provided on the accumulation of mutations in the mitochondrial DNA (mtDNA) during the aging process. However, the lack of direct functional consequences of the mutant mtDNA load on the mitochondria-dependent cell metabolism has raised many questions on the physiological importance of the age-related mtDNA variations. In the present work, we have analyzed the bioenergetic properties associated with the age-related T414G mutation of the mtDNA control region in transmitochondrial cybrids. The results show that the T414G mutation does not cause per se any detectable bioenergetic change. Moreover, three mtDNA mutations clustered in the 16S ribosomal RNA gene cosegregated together with the T414G in the same cybrid cell line. Two of them, namely T1843C and A1940G, are novel and associate with a negative bioenergetic phenotype. The results are discussed in the more general context of the complex heterogeneity and the dramatic instability of the mitochondrial genome during cell culture of transmitochondrial cybrids.

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Predicted secondary structure of the mitochondrial 16S rRNA. The nucleotides in the peptidyl transferase region (the multi-branched loop connecting helices G1–G2–G16–G17), which are relevant for catalytic activity or chloramphenicol binding in bacterial 23S rRNAs are highlighted in red. The mutations in mitochondrial 16S rRNA are also highlighted in red and their position within the rRNA is additionally indicated by red numbers. Base numbering is according to the Ribosomal Database: position 173 corresponds to T1843C; position 270 to A1940G, and position 953 to A2623G, respectively. The long-range interaction between C767 and A323 is depicted by a thin green line. For clarity, base and helix numbering is not contiguous.
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Figure 4: Predicted secondary structure of the mitochondrial 16S rRNA. The nucleotides in the peptidyl transferase region (the multi-branched loop connecting helices G1–G2–G16–G17), which are relevant for catalytic activity or chloramphenicol binding in bacterial 23S rRNAs are highlighted in red. The mutations in mitochondrial 16S rRNA are also highlighted in red and their position within the rRNA is additionally indicated by red numbers. Base numbering is according to the Ribosomal Database: position 173 corresponds to T1843C; position 270 to A1940G, and position 953 to A2623G, respectively. The long-range interaction between C767 and A323 is depicted by a thin green line. For clarity, base and helix numbering is not contiguous.

Mentions: As shown in Figure 4, the mutations relevant for the bioenergetic deficiency are not located in close proximity to the catalytic center of the rRNA, which is mainly formed by the central loop of domain VI (27). Instead, they are located in the 5′ part of the RNA. The role of the A1940G mutation (A270G in the RNA) is readily explained, because the change leads to formation of a G•U wobble pair instead of a regular A–U base pair, and thus will destabilize helix D8 in domain II. Although this helix is not directly linked to the catalytic region, a tertiary interaction between A323 in Loop D10 to C767 in the E16–E4 junction (green line in Figure 4) will bring this whole structure in close proximity to the peptidyl transferase center and may thus influence the overall stability of this domain.Figure 4.


Cosegregation of novel mitochondrial 16S rRNA gene mutations with the age-associated T414G variant in human cybrids.

Seibel P, Di Nunno C, Kukat C, Schäfer I, Del Bo R, Bordoni A, Comi GP, Schön A, Capuano F, Latorre D, Villani G - Nucleic Acids Res. (2008)

Predicted secondary structure of the mitochondrial 16S rRNA. The nucleotides in the peptidyl transferase region (the multi-branched loop connecting helices G1–G2–G16–G17), which are relevant for catalytic activity or chloramphenicol binding in bacterial 23S rRNAs are highlighted in red. The mutations in mitochondrial 16S rRNA are also highlighted in red and their position within the rRNA is additionally indicated by red numbers. Base numbering is according to the Ribosomal Database: position 173 corresponds to T1843C; position 270 to A1940G, and position 953 to A2623G, respectively. The long-range interaction between C767 and A323 is depicted by a thin green line. For clarity, base and helix numbering is not contiguous.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2566888&req=5

Figure 4: Predicted secondary structure of the mitochondrial 16S rRNA. The nucleotides in the peptidyl transferase region (the multi-branched loop connecting helices G1–G2–G16–G17), which are relevant for catalytic activity or chloramphenicol binding in bacterial 23S rRNAs are highlighted in red. The mutations in mitochondrial 16S rRNA are also highlighted in red and their position within the rRNA is additionally indicated by red numbers. Base numbering is according to the Ribosomal Database: position 173 corresponds to T1843C; position 270 to A1940G, and position 953 to A2623G, respectively. The long-range interaction between C767 and A323 is depicted by a thin green line. For clarity, base and helix numbering is not contiguous.
Mentions: As shown in Figure 4, the mutations relevant for the bioenergetic deficiency are not located in close proximity to the catalytic center of the rRNA, which is mainly formed by the central loop of domain VI (27). Instead, they are located in the 5′ part of the RNA. The role of the A1940G mutation (A270G in the RNA) is readily explained, because the change leads to formation of a G•U wobble pair instead of a regular A–U base pair, and thus will destabilize helix D8 in domain II. Although this helix is not directly linked to the catalytic region, a tertiary interaction between A323 in Loop D10 to C767 in the E16–E4 junction (green line in Figure 4) will bring this whole structure in close proximity to the peptidyl transferase center and may thus influence the overall stability of this domain.Figure 4.

Bottom Line: In the present work, we have analyzed the bioenergetic properties associated with the age-related T414G mutation of the mtDNA control region in transmitochondrial cybrids.The results show that the T414G mutation does not cause per se any detectable bioenergetic change.The results are discussed in the more general context of the complex heterogeneity and the dramatic instability of the mitochondrial genome during cell culture of transmitochondrial cybrids.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Cell Therapy, Center for Biotechnology and Biomedicine, Universität Leipzig, Deutscher Platz 5, 04103 Leipzig, Germany. peter.seibel@bbz.uni-leipzig.de

ABSTRACT
Ever increasing evidence has been provided on the accumulation of mutations in the mitochondrial DNA (mtDNA) during the aging process. However, the lack of direct functional consequences of the mutant mtDNA load on the mitochondria-dependent cell metabolism has raised many questions on the physiological importance of the age-related mtDNA variations. In the present work, we have analyzed the bioenergetic properties associated with the age-related T414G mutation of the mtDNA control region in transmitochondrial cybrids. The results show that the T414G mutation does not cause per se any detectable bioenergetic change. Moreover, three mtDNA mutations clustered in the 16S ribosomal RNA gene cosegregated together with the T414G in the same cybrid cell line. Two of them, namely T1843C and A1940G, are novel and associate with a negative bioenergetic phenotype. The results are discussed in the more general context of the complex heterogeneity and the dramatic instability of the mitochondrial genome during cell culture of transmitochondrial cybrids.

Show MeSH