scholarly journals Human Cytomegalovirus Infection Upregulates the Mitochondrial Transcription and Translation Machineries

mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
S. Karniely ◽  
M. P. Weekes ◽  
R. Antrobus ◽  
J. Rorbach ◽  
L. van Haute ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Human Cytomegalovirus ◽  
Mitochondrial Biogenesis ◽  
Ribosome Biogenesis ◽  
Hcmv Infection ◽  
Aerobic Glycolysis ◽  
Tricarboxylic Acid Cycle ◽  
Mitochondrial Translation ◽  
Mitochondrial Transcription ◽  
Mitochondrial Ribosome

ABSTRACT Infection with human cytomegalovirus (HCMV) profoundly affects cellular metabolism. Like in tumor cells, HCMV infection increases glycolysis, and glucose carbon is shifted from the mitochondrial tricarboxylic acid cycle to the biosynthesis of fatty acids. However, unlike in many tumor cells, where aerobic glycolysis is accompanied by suppression of mitochondrial oxidative phosphorylation, HCMV induces mitochondrial biogenesis and respiration. Here, we affinity purified mitochondria and used quantitative mass spectrometry to determine how the mitochondrial proteome changes upon HCMV infection. We found that the mitochondrial transcription and translation systems are induced early during the viral replication cycle. Specifically, proteins involved in biogenesis of the mitochondrial ribosome were highly upregulated by HCMV infection. Inhibition of mitochondrial translation with chloramphenicol or knockdown of HCMV-induced ribosome biogenesis factor MRM3 abolished the HCMV-mediated increase in mitochondrially encoded proteins and significantly impaired viral growth under bioenergetically restricting conditions. Our findings demonstrate how HCMV manipulates mitochondrial biogenesis to support its replication. IMPORTANCE Human cytomegalovirus (HCMV), a betaherpesvirus, is a leading cause of morbidity and mortality during congenital infection and among immunosuppressed individuals. HCMV infection significantly changes cellular metabolism. Akin to tumor cells, in HCMV-infected cells, glycolysis is increased and glucose carbon is shifted from the tricarboxylic acid cycle to fatty acid biosynthesis. However, unlike in tumor cells, HCMV induces mitochondrial biogenesis even under aerobic glycolysis. Here, we have affinity purified mitochondria and used quantitative mass spectrometry to determine how the mitochondrial proteome changes upon HCMV infection. We find that the mitochondrial transcription and translation systems are induced early during the viral replication cycle. Specifically, proteins involved in biogenesis of the mitochondrial ribosome were highly upregulated by HCMV infection. Inhibition of mitochondrial translation with chloramphenicol or knockdown of HCMV-induced ribosome biogenesis factor MRM3 abolished the HCMV-mediated increase in mitochondrially encoded proteins and significantly impaired viral growth. Our findings demonstrate how HCMV manipulates mitochondrial biogenesis to support its replication.

Hypoxia boosts aerobic glycolysis of carcinoma：a complex process for tumor development

2021 ◽  
Vol 14 ◽  
Author(s):  
Xiuqin Zheng ◽  
Hui Fan ◽  
Yang Liu ◽  
Zhonghong Wei ◽  
Xiaoman Li ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Tumor Cells ◽  
Cancer Metastasis ◽  
Malignant Tumors ◽  
Aerobic Glycolysis ◽  
Tricarboxylic Acid Cycle ◽  
Tumor Development ◽  
Hypoxic Conditions ◽  
The Stability ◽  
Cancer Tissues

: Hypoxia, a common feature in malignant tumors, is mainly caused by insufficient oxygen supply. Hypoxia is closely related to cancer development, affecting cancer invasion and metastasis, energy metabolism and other pathological processes, and is not conducive to cancer treatment and prognosis. Tumor cells exacerbate metabolic abnormalities to adapt to the hypoxic microenvironment, especially to enhance aerobic glycolysis. Glycolysis leads to an acidic microenvironment in cancer tissues, enhancing cancer metastasis, deterioration and drug resistance. Therefore, hypoxia is a therapeutic target that cannot be ignored in cancer treatment. The adaptation of tumor cells to hypoxia is mainly regulated by hypoxia inducible factors (HIFs), and the stability of HIFs is improved under hypoxic conditions. HIFs can promote the glycolysis of tumors by regulating glycolytic enzymes, transporters, and participates in regulating the TCA (tricarboxylic acid) cycle. In addition, HIFs indirectly affect glycolysis through its interaction with non-coding RNAs. Therefore, targeting hypoxia and HIFs are important tumor therapies.

scholarly journals A late-stage assembly checkpoint of the human mitochondrial ribosome large subunit

2021 ◽  
Author(s):  
Pedro Rebelo-Guiomar ◽  
Simone Pellegrino ◽  
Kyle Dent ◽  
Aldema Sas- Chen ◽  
Leonor Miller-Fleming ◽  
...  
Keyword(s):  
Late Stage ◽  
Ribosome Biogenesis ◽  
Essential Gene ◽  
Large Subunit ◽  
Mitochondrial Translation ◽  
Cellular Processes ◽  
Mitochondrial Ribosome ◽  
Severe Impairment ◽  
Control Step ◽  
Rna Domains

The epitranscriptome plays a key regulatory role in cellular processes in health and disease, including ribosome biogenesis. Here, analysis of the human mitochondrial transcriptome shows that 2'-O-methylation is limited to residues of the mitoribosomal large subunit (mtLSU) 16S mt-rRNA, modified by MRM1, MRM2, and MRM3. Ablation of MRM2 leads to a severe impairment of the oxidative phosphorylation system, caused by defective mitochondrial translation and accumulation of mtLSU assembly intermediates. Structures of these particles (2.58 Å) present disordered RNA domains, partial occupancy of bL36m and bound MALSU1:L0R8F8:mtACP anti-association module. Additionally, we present five mtLSU assembly states with different intersubunit interface configurations. Complementation studies demonstrate that the methyltransferase activity of MRM2 is dispensable for mitoribosome biogenesis. The Drosophila melanogaster orthologue, DmMRM2, is an essential gene, with its knock- down leading to developmental arrest. This work identifies a key late-stage quality control step during mtLSU assembly, ultimately contributing to the maintenance of mitochondrial homeostasis.

scholarly journals YBEY is an essential biogenesis factor for mitochondrial ribosomes

2019 ◽  
Author(s):  
Sabrina Summer ◽  
Anna Smirnova ◽  
Alessandro Gabriele ◽  
Ursula Toth ◽  
Fasemore Mandela ◽  
...  
Keyword(s):  
16S Rrna ◽  
Ribosome Biogenesis ◽  
Specific Interaction ◽  
Ribosomal Subunit ◽  
Small Subunit ◽  
12S Rrna ◽  
Mitochondrial Translation ◽  
Mitochondrial Ribosomes ◽  
Mitochondrial Ribosome ◽  
Abnormal Mitochondria

ABSTRACTRibosome biogenesis requires numerous trans-acting factors, some of which are deeply conserved. In Bacteria, the endoribonuclease YbeY is believed to be involved in 16S rRNA 3’-end processing and its loss was associated with ribosomal abnormalities. In Eukarya, YBEY appears to generally localize to mitochondria (or chloroplasts). Here we show that the deletion of human YBEY results in a severe respiratory deficiency and morphologically abnormal mitochondria as an apparent consequence of impaired mitochondrial translation. Reduced stability of 12S rRNA and the deficiency of several proteins of the small ribosomal subunit in YBEY knockout cells pointed towards a defect in mitochondrial ribosome biogenesis. The specific interaction of mitoribosomal protein uS11m with YBEY suggests that the latter recruits uS11m to the nascent small subunit in its late assembly stage. This scenario shows similarities with final stages of cytosolic ribosome biogenesis, and may represent a late checkpoint before the mitoribosome engages in translation.

scholarly journals YBEY is an essential biogenesis factor for mitochondrial ribosomes

2020 ◽  
Vol 48 (17) ◽  
pp. 9762-9786 ◽  
Author(s):  
Sabrina Summer ◽  
Anna Smirnova ◽  
Alessandro Gabriele ◽  
Ursula Toth ◽  
Akinyemi Mandela Fasemore ◽  
...  
Keyword(s):  
16S Rrna ◽  
Ribosome Biogenesis ◽  
Specific Interaction ◽  
Ribosomal Subunit ◽  
Small Subunit ◽  
12S Rrna ◽  
Mitochondrial Translation ◽  
Mitochondrial Ribosomes ◽  
Mitochondrial Ribosome ◽  
Abnormal Mitochondria

Abstract Ribosome biogenesis requires numerous trans-acting factors, some of which are deeply conserved. In Bacteria, the endoribonuclease YbeY is believed to be involved in 16S rRNA 3′-end processing and its loss was associated with ribosomal abnormalities. In Eukarya, YBEY appears to generally localize to mitochondria (or chloroplasts). Here we show that the deletion of human YBEY results in a severe respiratory deficiency and morphologically abnormal mitochondria as an apparent consequence of impaired mitochondrial translation. Reduced stability of 12S rRNA and the deficiency of several proteins of the small ribosomal subunit in YBEY knockout cells pointed towards a defect in mitochondrial ribosome biogenesis. The specific interaction of mitoribosomal protein uS11m with YBEY suggests that the latter helps to properly incorporate uS11m into the nascent small subunit in its late assembly stage. This scenario shows similarities with final stages of cytosolic ribosome biogenesis, and may represent a late checkpoint before the mitoribosome engages in translation.

scholarly journals The conserved interaction of C7orf30 with MRPL14 promotes biogenesis of the mitochondrial large ribosomal subunit and mitochondrial translation

2013 ◽  
Vol 24 (3) ◽  
pp. 184-193 ◽  
Author(s):  
Stephen Fung ◽  
Tamiko Nishimura ◽  
Florin Sasarman ◽  
Eric A. Shoubridge
Keyword(s):  
Ribosome Biogenesis ◽  
Ribosomal Subunit ◽  
Large Family ◽  
Large Ribosomal Subunit ◽  
Mitochondrial Translation ◽  
Interacting Protein ◽  
Mitochondrial Ribosome ◽  
Essential Components ◽  
Translation Apparatus ◽  
Interfering Rna

Mammalian mitochondria harbor a dedicated translation apparatus that is required for the synthesis of 13 mitochondrial DNA (mtDNA)-encoded polypeptides, all of which are essential components of the oxidative phosphorylation (OXPHOS) complexes. Little is known about the mechanism of assembly of the mitoribosomes that catalyze this process. Here we show that C7orf30, a member of the large family of DUF143 proteins, associates with the mitochondrial large ribosomal subunit (mt-LSU). Knockdown of C7orf30 by short hairpin RNA (shRNA) does not alter the sedimentation profile of the mt-LSU, but results in the depletion of several mt-LSU proteins and decreased monosome formation. This leads to a mitochondrial translation defect, involving the majority of mitochondrial polypeptides, and a severe OXPHOS assembly defect. Immunoprecipitation and mass spectrometry analyses identified mitochondrial ribosomal protein (MRP)L14 as the specific interacting protein partner of C7orf30 in the mt-LSU. Reciprocal experiments in which MRPL14 was depleted by small interfering RNA (siRNA) phenocopied the C7orf30 knockdown. Members of the DUF143 family have been suggested to be universally conserved ribosomal silencing factors, acting by sterically inhibiting the association of the small and large ribosomal subunits. Our results demonstrate that, although the interaction between C7orf30 and MRPL14 has been evolutionarily conserved, human C7orf30 is, on the contrary, essential for mitochondrial ribosome biogenesis and mitochondrial translation.

scholarly journals The Yeast GTPase Mtg2p Is Required for Mitochondrial Translation and Partially Suppresses an rRNA Methyltransferase Mutant,mrm2

2005 ◽  
Vol 16 (2) ◽  
pp. 954-963 ◽  
Author(s):  
Kaustuv Datta ◽  
Jennifer L. Fuentes ◽  
Janine R. Maddock
Keyword(s):  
Mitochondrial Dna ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Mitochondrial Protein ◽  
Ribosomal Subunit ◽  
Temporal Association ◽  
Temperature Sensitive ◽  
Dependent Manner ◽  
Mitochondrial Translation ◽  
Mitochondrial Ribosome

The assembly of ribosomes involves the coordinated processing and modification of rRNAs with the temporal association of ribosomal proteins. This process is regulated by assembly factors such as helicases, modifying enzymes, and GTPases. In contrast to the assembly of cytoplasmic ribosomes, there is a paucity of information concerning the role of assembly proteins in the biogenesis of mitochondrial ribosomes. In this study, we demonstrate that the Saccharomyces cerevisiae GTPase Mtg2p (Yhr168wp) is essential for mitochondrial ribosome function. Cells lacking MTG2 lose their mitochondrial DNA, giving rise to petite cells. In addition, cells expressing a temperature-sensitive mgt2-1 allele are defective in mitochondrial protein synthesis and contain lowered levels of mitochondrial ribosomal subunits. Significantly, elevated levels of Mtg2p partially suppress the thermosensitive loss of mitochondrial DNA in a 21S rRNA methyltransferase mutant, mrm2. We propose that Mtg2p is involved in mitochondrial ribosome biogenesis. Consistent with this role, we show that Mtg2p is peripherally localized to the mitochondrial inner membrane and associates with the 54S large ribosomal subunit in a salt-dependent manner.

scholarly journals Structural basis of GTPase-mediated mitochondrial ribosome biogenesis and recycling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hauke S. Hillen ◽  
Elena Lavdovskaia ◽  
Franziska Nadler ◽  
Elisa Hanitsch ◽  
Andreas Linden ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Ribosomal Subunit ◽  
Structural Basis ◽  
Peptidyl Transferase ◽  
Mitochondrial Ribosomes ◽  
Mitochondrial Ribosome ◽  
In Vitro Reconstitution

AbstractRibosome biogenesis requires auxiliary factors to promote folding and assembly of ribosomal proteins and RNA. Particularly, maturation of the peptidyl transferase center (PTC) is mediated by conserved GTPases, but the molecular basis is poorly understood. Here, we define the mechanism of GTPase-driven maturation of the human mitochondrial large ribosomal subunit (mtLSU) using endogenous complex purification, in vitro reconstitution and cryo-EM. Structures of transient native mtLSU assembly intermediates that accumulate in GTPBP6-deficient cells reveal how the biogenesis factors GTPBP5, MTERF4 and NSUN4 facilitate PTC folding. Addition of recombinant GTPBP6 reconstitutes late mtLSU biogenesis in vitro and shows that GTPBP6 triggers a molecular switch and progression to a near-mature PTC state. Additionally, cryo-EM analysis of GTPBP6-treated mature mitochondrial ribosomes reveals the structural basis for the dual-role of GTPBP6 in ribosome biogenesis and recycling. Together, these results provide a framework for understanding step-wise PTC folding as a critical conserved quality control checkpoint.

scholarly journals Ketogenic diets inhibit mitochondrial biogenesis and induce cardiac fibrosis

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Sha Xu ◽  
Hui Tao ◽  
Wei Cao ◽  
Li Cao ◽  
Yan Lin ◽  
...  
Keyword(s):  
Mitochondrial Biogenesis ◽  
Ketone Body ◽  
Cardiac Fibrosis ◽  
Cardiomyocyte Apoptosis ◽  
Healthy Individuals ◽  
Cell Respiration ◽  
Ketogenic Diets ◽  
Mitochondrial Ribosome ◽  
Encoding Genes ◽  
Human Atrial Fibrillation

AbstractIn addition to their use in relieving the symptoms of various diseases, ketogenic diets (KDs) have also been adopted by healthy individuals to prevent being overweight. Herein, we reported that prolonged KD exposure induced cardiac fibrosis. In rats, KD or frequent deep fasting decreased mitochondrial biogenesis, reduced cell respiration, and increased cardiomyocyte apoptosis and cardiac fibrosis. Mechanistically, increased levels of the ketone body β-hydroxybutyrate (β-OHB), an HDAC2 inhibitor, promoted histone acetylation of the Sirt7 promoter and activated Sirt7 transcription. This in turn inhibited the transcription of mitochondrial ribosome-encoding genes and mitochondrial biogenesis, leading to cardiomyocyte apoptosis and cardiac fibrosis. Exogenous β-OHB administration mimicked the effects of a KD in rats. Notably, increased β-OHB levels and SIRT7 expression, decreased mitochondrial biogenesis, and increased cardiac fibrosis were detected in human atrial fibrillation heart tissues. Our results highlighted the unknown detrimental effects of KDs and provided insights into strategies for preventing cardiac fibrosis in patients for whom KDs are medically necessary.

scholarly journals Proteomic profiling of the mitochondrial ribosome identifies Atp25 as a composite mitochondrial precursor protein

2016 ◽  
Vol 27 (20) ◽  
pp. 3031-3039 ◽  
Author(s):  
Michael W. Woellhaf ◽  
Frederik Sommer ◽  
Michael Schroda ◽  
Johannes M. Herrmann
Keyword(s):  
Precursor Protein ◽  
Ribosomal Biogenesis ◽  
Proteomic Profiling ◽  
Mitochondrial Translation ◽  
Bacterial Ribosome ◽  
Mitochondrial Ribosome ◽  
Translation Apparatus ◽  
The Matrix ◽  
Processing Peptidase ◽  
And Function

Whereas the structure and function of cytosolic ribosomes are well characterized, we only have a limited understanding of the mitochondrial translation apparatus. Using SILAC-based proteomic profiling, we identified 13 proteins that cofractionated with the mitochondrial ribosome, most of which play a role in translation or ribosomal biogenesis. One of these proteins is a homologue of the bacterial ribosome-silencing factor (Rsf). This protein is generated from the composite precursor protein Atp25 upon internal cleavage by the matrix processing peptidase MPP, and in this respect, it differs from all other characterized mitochondrial proteins of baker’s yeast. We observed that cytosolic expression of Rsf, but not of noncleaved Atp25 protein, is toxic. Our results suggest that eukaryotic cells face the challenge of avoiding negative interference from the biogenesis of their two distinct translation machineries.

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