Energy metabolism and cytochrome oxidase activity: linking metabolism to gene expression

2014 ◽  
Vol 92 (7) ◽  
pp. 557-568 ◽  
Author(s):  
K. Bremer ◽  
K.M. Kocha ◽  
T. Snider ◽  
C.D. Moyes

Modification of mitochondrial content demands the synthesis of hundreds of proteins encoded by nuclear and mitochondrial genomes. The responsibility for coordination of this process falls to nuclear-encoded master regulators of transcription. DNA-binding proteins and coactivators integrate information from energy-sensing pathways and hormones to alter mitochondrial gene expression. In mammals, the signaling cascade for mitochondrial biogenesis can be described as follows: hormonal signals and energetic information are sensed by protein-modifying enzymes that in turn regulate the post-translational modification of transcription factors. Once activated, transcription-factor complexes form on promoter elements of many of the nuclear-encoded mitochondrial genes, recruiting proteins that remodel chromatin and initiate transcription. One master regulator in mammals, PGC-1α, is well studied because of its role in determining the metabolic phenotype of muscles, but also due to its importance in mitochondria-related metabolic diseases. However, relatively little is known about the role of this pathway in other vertebrates. These uncertainties raise broader questions about the evolutionary origins of the pathway and its role in generating the diversity in muscle metabolic phenotypes seen in nature.

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 757-760 ◽  
Author(s):  
Ronald A. Butow ◽  
Hong Zhu ◽  
Philip Perlman ◽  
Heather Conrad-Webb

All mRNAs on the yeast mitochondrial genome terminate at a conserved dodecamer sequence 5′-AAUAAUAUUCUU-3′. We have characterized two mutants with altered dodecamers. One contains a deletion of the dodecamer at the end of the var1 gene, and the other contains two adjacent transversions in the dodecamer at the end of the reading frame of fit1, a gene within the ω+ allele of the 21S rRNA gene. In each mutant, expression of the respective gene is blocked completely. A dominant nuclear suppressor, SUV3-1, was isolated that suppresses the var1 deletion but is without effect on the fit1 dodecamer mutations. Unexpectedly, however, we found that SUV3-1 blocks expression of the wild-type fit1 allele by blocking processing at its dodecamer. SUV3-1 has pleiotropic effects on mitochondrial gene expression, affecting RNA processing, RNA stability, and translation. Our results suggest that RNA metabolism and translation may be part of a multicomponent complex within mitochondria.Key words: mitochondria, yeast, mRNA, RNA processing, 3′ dodecamer.


2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Camille Lefevre ◽  
Baptiste Panthu ◽  
Danielle Naville ◽  
Sylvie Guibert ◽  
Claudie Pinteur ◽  
...  

White adipose tissues are functionally heterogeneous and differently manage the excess of energy supply. While the expansion of subcutaneous adipose tissues (SAT) is protective in obesity, that of visceral adipose tissues (VAT) correlates with the emergence of metabolic diseases. Maintained in fat pads throughout life, adipose stem cells (ASC) are mesenchymal-like stem cells with adipogenesis and multipotent differentiation potential. ASC from distinct fat pads have long been reported to present distinct proliferation and differentiation potentials that are maintained in culture, yet the origins of these intrinsic differences are still unknown. Metabolism is central to stem cell fate decision in line with environmental changes. In this study, we performed high-resolution nuclear magnetic resonance (NMR) metabolomic analyses of ASC culture supernatants in order to characterize their metabolic phenotype in culture. We identified and quantified 29 ASC exometabolites and evaluated their consumption or secretion over 72 h of cell culture. Both ASC used glycolysis and mitochondrial metabolism, as evidenced by the high secretions of lactate and citrate, respectively, but V-ASC mostly used glycolysis. By varying the composition of the cell culture medium, we showed that glutaminolysis, rather than glycolysis, supported the secretion of pyruvate, alanine, and citrate, evidencing a peculiar metabolism in ASC cells. The comparison of the two types of ASC in glutamine-free culture conditions also revealed the role of glutaminolysis in the limitation of pyruvate routing towards the lactate synthesis, in S-ASC but not in V-ASC. Altogether, our results suggest a difference between depots in the capacity of ASC mitochondria to assimilate pyruvate, with probable consequences on their differentiation potential in pathways requiring an increased mitochondrial activity. These results highlight a pivotal role of metabolic mechanisms in the discrimination between ASC and provide new perspectives in the understanding of their functional differences.


2001 ◽  
Vol 1 (S1) ◽  
Author(s):  
H van der Spek ◽  
M Siep ◽  
L de Jong ◽  
SDJ Elzinga ◽  
K van Oosterum ◽  
...  

2006 ◽  
Vol 12 (8) ◽  
pp. S162-S163
Author(s):  
Yasuaki Nakagawa ◽  
Koichiro Kuwahara ◽  
Masaki Harada ◽  
Genzo Takemura ◽  
Masaharu Akao ◽  
...  

2001 ◽  
Vol 54 ◽  
pp. S11-S27 ◽  
Author(s):  
Carolyn D Berdanier ◽  
Helen B Everts ◽  
Christina Hermoyian ◽  
Clayton E Mathews

2003 ◽  
Vol 358 (1429) ◽  
pp. 181-189 ◽  
Author(s):  
Stefan Binder ◽  
Axel Brennicke

The informational content of the mitochondrial genome in plants is, although small, essential for each cell. Gene expression in these organelles involves a number of distinct transcriptional and post–transcriptional steps. The complex post–transcriptional processes of plant mitochondria such as 5′ and 3′ RNA processing, intron splicing, RNA editing and controlled RNA stability extensively modify individual steady–state RNA levels and influence the mRNA quantities available for translation. In this overview of the processes in mitochondrial gene expression, we focus on confirmed and potential sites of regulatory interference and discuss the evolutionary origins of the transcriptional and post–transcriptional processes.


Author(s):  
Kévin Tartour ◽  
Kiran Padmanabhan

Circadian rhythms orchestrate organismal physiology and behavior in order to anticipate daily changes in the environment. Virtually all cells have an internal rhythm that is synchronized every day by Zeitgebers (environmental cues). The synchrony between clocks within the animal enables the fitness and the health of organisms. Conversely, disruption of rhythms is linked to a variety of disorders: aging, cancer, metabolic diseases, and psychological disorders among others. At the cellular level, mammalian circadian rhythms are built on several layers of complexity. The transcriptional-translational feedback loop (TTFL) was the first to be described in the 90s. Thereafter oscillations in epigenetic marks highlighted the role of chromatin state in organizing the TTFL. More recently, studies on the 3D organization of the genome suggest that genome topology could be yet another layer of control on cellular circadian rhythms. The dynamic nature of genome topology over a solar day implies that the 3D mammalian genome has to be considered in the fourth dimension-in time. Whether oscillations in genome topology are a consequence of 24 h gene-expression or a driver of transcriptional cycles remains an open question. All said and done, circadian clock-gated phenomena such as gene expression, DNA damage response, cell metabolism and animal behavior—go hand in hand with 24 h rhythms in genome topology.


Cytokine ◽  
2010 ◽  
Vol 52 (1-2) ◽  
pp. 29
Author(s):  
Jennifer D. Sisler ◽  
Magdalena Szelag ◽  
Ramesh Potla ◽  
Qifang Zhang ◽  
Karol Szczepanek ◽  
...  

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