Reduced TOR Signaling Extends Chronological Life Span via Increased Respiration and Upregulation of Mitochondrial Gene Expression

The cellular energy metabolism is one of the most conserved processes, as it is present in all living organisms. Mitochondria are providing the eukaryotic cell with energy and thus their genome and gene expression has been of broad interest for a long time. Mitochondrial gene expression changes under different conditions and is regulated by genes encoded in the nucleus of the cell. In this context, little is known about non-model organisms and we provide the first large-scaled gene expression analysis of mitochondrial-linked genes in laying hens. We analysed 28 mitochondrial and nuclear genes in 100 individuals in the context of five life-stages and strain differences among five tissues. Our study showed that mitochondrial gene expression increases during the productive life span, and reacts tissue and strain specific. In addition, the strains react different to potential increased oxidative stress, resulting from the increase in mitochondrial gene expression. The results suggest that the cellular energy metabolism as part of a complex regulatory system is strongly affected by the productive life span in laying hens and thus partly comparable to model organisms. This study provides a starting point for further analyses in this field on non-model organisms, especially in laying-hens.

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Defective Mitochondrial Gene Expression Results in Reactive Oxygen Species-Mediated Inhibition of Respiration and Reduction of Yeast Life Span

Molecular and Cellular Biology ◽

10.1128/mcb.02360-05 ◽

2006 ◽

Vol 26 (13) ◽

pp. 4818-4829 ◽

Cited By ~ 89

Author(s):

Nicholas D. Bonawitz ◽

Matthew S. Rodeheffer ◽

Gerald S. Shadel

Keyword(s):

Oxidative Stress ◽

Gene Expression ◽

Reactive Oxygen Species ◽

Life Span ◽

Mitochondrial Gene ◽

Reactive Oxygen ◽

Oxygen Species ◽

Mitochondrial Gene Expression ◽

Mitochondrial Translation ◽

Amino Terminal

ABSTRACT Mitochondrial dysfunction causes numerous human diseases and is widely believed to be involved in aging. However, mechanisms through which compromised mitochondrial gene expression elicits the reported variety of cellular defects remain unclear. The amino-terminal domain (ATD) of yeast mitochondrial RNA polymerase is required to couple transcription to translation during expression of mitochondrial DNA-encoded oxidative phosphorylation subunits. Here we report that several ATD mutants exhibit reduced chronological life span. The most severe of these (harboring the rpo41-R129D mutation) displays imbalanced mitochondrial translation, conditional inactivation of respiration, elevated production of reactive oxygen species (ROS), and increased oxidative stress. Reduction of ROS, via overexpression of superoxide dismutase (SOD1 or SOD2 product), not only greatly extends the life span of this mutant but also increases its ability to respire. Another ATD mutant with similarly reduced respiration (rpo41-D152A/D154A) accumulates only intermediate levels of ROS and has a less severe life span defect that is not rescued by SOD. Altogether, our results provide compelling evidence for the “vicious cycle” of mitochondrial ROS production and lead us to propose that the amount of ROS generated depends on the precise nature of the mitochondrial gene expression defect and initiates a downward spiral of oxidative stress only if a critical threshold is crossed.

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Faculty Opinions recommendation of Adult-onset obesity is triggered by impaired mitochondrial gene expression.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.728768996.793536505 ◽

2017 ◽

Author(s):

Michael Miller ◽

Ekta Tiwary

Keyword(s):

Gene Expression ◽

Mitochondrial Gene ◽

Mitochondrial Gene Expression ◽

Adult Onset

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Neuroprotection by Progesterone through Stimulation of Mitochondrial Gene Expression

10.21236/ada392823 ◽

2000 ◽

Author(s):

Gary Fiskum

Keyword(s):

Gene Expression ◽

Mitochondrial Gene ◽

Mitochondrial Gene Expression ◽

Stimulation Of

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Mitochondrial Glucocorticoid Receptors and Their Actions

International Journal of Molecular Sciences ◽

10.3390/ijms22116054 ◽

2021 ◽

Vol 22 (11) ◽

pp. 6054

Author(s):

Ioanna Kokkinopoulou ◽

Paraskevi Moutsatsou

Keyword(s):

Gene Expression ◽

Glucocorticoid Receptors ◽

Mitochondrial Gene ◽

Cell Types ◽

Ros Generation ◽

Mitochondrial Gene Expression ◽

Mitochondrial Energy Metabolism ◽

Bcl2 Family ◽

Cellular Processes ◽

Almost All

Mitochondria are membrane organelles present in almost all eukaryotic cells. In addition to their well-known role in energy production, mitochondria regulate central cellular processes, including calcium homeostasis, Reactive Oxygen Species (ROS) generation, cell death, thermogenesis, and biosynthesis of lipids, nucleic acids, and steroid hormones. Glucocorticoids (GCs) regulate the mitochondrially encoded oxidative phosphorylation gene expression and mitochondrial energy metabolism. The identification of Glucocorticoid Response Elements (GREs) in mitochondrial sequences and the detection of Glucocorticoid Receptor (GR) in mitochondria of different cell types gave support to hypothesis that mitochondrial GR directly regulates mitochondrial gene expression. Numerous studies have revealed changes in mitochondrial gene expression alongside with GR import/export in mitochondria, confirming the direct effects of GCs on mitochondrial genome. Further evidence has made clear that mitochondrial GR is involved in mitochondrial function and apoptosis-mediated processes, through interacting or altering the distribution of Bcl2 family members. Even though its exact translocation mechanisms remain unknown, data have shown that GR chaperones (Hsp70/90, Bag-1, FKBP51), the anti-apoptotic protein Bcl-2, the HDAC6- mediated deacetylation and the outer mitochondrial translocation complexes (Tom complexes) co-ordinate GR mitochondrial trafficking. A role of mitochondrial GR in stress and depression as well as in lung and hepatic inflammation has also been demonstrated.

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Mitochondrial Mistranslation in Brain Provokes a Metabolic Response Which Mitigates the Age-Associated Decline in Mitochondrial Gene Expression

International Journal of Molecular Sciences ◽

10.3390/ijms22052746 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2746

Author(s):

Dimitri Shcherbakov ◽

Reda Juskeviciene ◽

Adrián Cortés Sanchón ◽

Margarita Brilkova ◽

Hubert Rehrauer ◽

...

Keyword(s):

Gene Expression ◽

Metabolic Response ◽

Mitochondrial Gene ◽

Tca Cycle ◽

Brain Mitochondria ◽

Mitochondrial Gene Expression ◽

Rna Seq ◽

The Tca Cycle ◽

Neurological Phenotype

Mitochondrial misreading, conferred by mutation V338Y in mitoribosomal protein Mrps5, in-vivo is associated with a subtle neurological phenotype. Brain mitochondria of homozygous knock-in mutant Mrps5V338Y/V338Y mice show decreased oxygen consumption and reduced ATP levels. Using a combination of unbiased RNA-Seq with untargeted metabolomics, we here demonstrate a concerted response, which alleviates the impaired functionality of OXPHOS complexes in Mrps5 mutant mice. This concerted response mitigates the age-associated decline in mitochondrial gene expression and compensates for impaired respiration by transcriptional upregulation of OXPHOS components together with anaplerotic replenishment of the TCA cycle (pyruvate, 2-ketoglutarate).

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Regulation of nuclear and mitochondrial gene expression by contractile activity in skeletal muscle.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)42482-3 ◽

1986 ◽

Vol 261 (1) ◽

pp. 376-380 ◽

Cited By ~ 15

Author(s):

R S Williams ◽

S Salmons ◽

E A Newsholme ◽

R E Kaufman ◽

J Mellor

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Contractile Activity ◽

Mitochondrial Gene ◽

Mitochondrial Gene Expression

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Quantitative proteomics revealed C6orf203/MTRES1 as a factor preventing stress-induced transcription deficiency in human mitochondria

Nucleic Acids Research ◽

10.1093/nar/gkz542 ◽

2019 ◽

Vol 47 (14) ◽

pp. 7502-7517 ◽

Cited By ~ 6

Author(s):

Anna V Kotrys ◽

Dominik Cysewski ◽

Sylwia D Czarnomska ◽

Zbigniew Pietras ◽

Lukasz S Borowski ◽

...

Keyword(s):

Gene Expression ◽

Rna Binding ◽

Mitochondrial Gene ◽

Binding Activity ◽

Stress Conditions ◽

Mitochondrial Rna ◽

Mitochondrial Gene Expression ◽

Compensatory Mechanisms ◽

Temporary Reduction ◽

Mitochondrial Transcription

AbstractMaintenance of mitochondrial gene expression is crucial for cellular homeostasis. Stress conditions may lead to a temporary reduction of mitochondrial genome copy number, raising the risk of insufficient expression of mitochondrial encoded genes. Little is known how compensatory mechanisms operate to maintain proper mitochondrial transcripts levels upon disturbed transcription and which proteins are involved in them. Here we performed a quantitative proteomic screen to search for proteins that sustain expression of mtDNA under stress conditions. Analysis of stress-induced changes of the human mitochondrial proteome led to the identification of several proteins with poorly defined functions among which we focused on C6orf203, which we named MTRES1 (Mitochondrial Transcription Rescue Factor 1). We found that the level of MTRES1 is elevated in cells under stress and we show that this upregulation of MTRES1 prevents mitochondrial transcript loss under perturbed mitochondrial gene expression. This protective effect depends on the RNA binding activity of MTRES1. Functional analysis revealed that MTRES1 associates with mitochondrial RNA polymerase POLRMT and acts by increasing mitochondrial transcription, without changing the stability of mitochondrial RNAs. We propose that MTRES1 is an example of a protein that protects the cell from mitochondrial RNA loss during stress.

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