scholarly journals Atp10p Assists Assembly of Atp6p into the F0Unit of the Yeast Mitochondrial ATPase

2004 ◽  
Vol 279 (19) ◽  
pp. 19775-19780 ◽  
Author(s):  
Alexander Tzagoloff ◽  
Antoni Barrientos ◽  
Walter Neupert ◽  
Johannes M. Herrmann
Keyword(s):  
Nuclear Gene ◽  
Mitochondrial Atpase ◽  
Gene Products ◽  
Wild Type ◽  
Mitochondrial Translation ◽  
Mitochondrial Ribosomes ◽  
Mitochondrial Inner Membrane ◽  
Atpase Subunits ◽  
Specific Factors

The F0F1-ATPase complex of yeast mitochondria contains three mitochondrial and at least 17 nuclear gene products. The coordinate assembly of mitochondrial and cytosolic translation products relies on chaperones and specific factors that stabilize the pools of some unassembled subunits. Atp10p was identified as a mitochondrial inner membrane component necessary for the biogenesis of the hydrophobic F0sector of the ATPase. Here we show that, following its synthesis on mitochondrial ribosomes, subunit 6 of the ATPase (Atp6p) can be cross-linked to Atp10p. This interaction is required for the integration of Atp6p into a partially assembled subcomplex of the ATPase. Pulse labeling and chase of mitochondrial translation productsin vivoindicate that Atp6p is less stable and more rapidly degraded in anatp10null mutant than in wild type. Based on these observations, we propose Atp10p to be an Atp6p-specific chaperone that facilitates the incorporation of Atp6p into an intermediate subcomplex of ATPase subunits.

Rpm2, the Protein Subunit of Mitochondrial RNase P in Saccharomyces cerevisiae, Also Has a Role in the Translation of Mitochondrially Encoded Subunits of Cytochrome c Oxidase

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 573-585
Author(s):  
Vilius Stribinskis ◽  
Guo-Jian Gao ◽  
Steven R Ellis ◽  
Nancy C Martin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Mitochondrial Biogenesis ◽  
Mitochondrial Protein ◽  
Nuclear Gene ◽  
Rnase P ◽  
Wild Type ◽  
Protein Subunit ◽  
Mitochondrial Translation

Abstract RPM2 is a Saccharomyces cerevisiae nuclear gene that encodes the protein subunit of mitochondrial RNase P and has an unknown function essential for fermentative growth. Cells lacking mitochondrial RNase P cannot respire and accumulate lesions in their mitochondrial DNA. The effects of a new RPM2 allele, rpm2-100, reveal a novel function of RPM2 in mitochondrial biogenesis. Cells with rpm2-100 as their only source of Rpm2p have correctly processed mitochondrial tRNAs but are still respiratory deficient. Mitochondrial mRNA and rRNA levels are reduced in rpm2-100 cells compared to wild type. The general reduction in mRNA is not reflected in a similar reduction in mitochondrial protein synthesis. Incorporation of labeled precursors into mitochondrially encoded Atp6, Atp8, Atp9, and Cytb protein was enhanced in the mutant relative to wild type, while incorporation into Cox1p, Cox2p, Cox3p, and Var1p was reduced. Pulse-chase analysis of mitochondrial translation revealed decreased rates of translation of COX1, COX2, and COX3 mRNAs. This decrease leads to low steady-state levels of Cox1p, Cox2p, and Cox3p, loss of visible spectra of aa3 cytochromes, and low cytochrome c oxidase activity in mutant mitochondria. Thus, RPM2 has a previously unrecognized role in mitochondrial biogenesis, in addition to its role as a subunit of mitochondrial RNase P. Moreover, there is a synthetic lethal interaction between the disruption of this novel respiratory function and the loss of wild-type mtDNA. This synthetic interaction explains why a complete deletion of RPM2 is lethal.

scholarly journals Fidelity of translation initiation is required for coordinated respiratory complex assembly

2019 ◽  
Vol 5 (12) ◽  
pp. eaay2118 ◽  
Author(s):  
Danielle L. Rudler ◽  
Laetitia A. Hughes ◽  
Kara L. Perks ◽  
Tara R. Richman ◽  
Irina Kuznetsova ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Mitochondrial Protein ◽  
Molecular Machines ◽  
Ribosome Profiling ◽  
Untranslated Regions ◽  
Mitochondrial Protein Synthesis ◽  
Mitochondrial Translation ◽  
Initiation Factors ◽  
Mitochondrial Ribosomes

Mammalian mitochondrial ribosomes are unique molecular machines that translate 11 leaderless mRNAs; however, it is not clear how mitoribosomes initiate translation, since mitochondrial mRNAs lack untranslated regions. Mitochondrial translation initiation shares similarities with prokaryotes, such as the formation of a ternary complex of fMet-tRNAMet, mRNA and the 28S subunit, but differs in the requirements for initiation factors. Mitochondria have two initiation factors: MTIF2, which closes the decoding center and stabilizes the binding of the fMet-tRNAMet to the leaderless mRNAs, and MTIF3, whose role is not clear. We show that MTIF3 is essential for survival and that heart- and skeletal muscle–specific loss of MTIF3 causes cardiomyopathy. We identify increased but uncoordinated mitochondrial protein synthesis in mice lacking MTIF3, resulting in loss of specific respiratory complexes. Ribosome profiling shows that MTIF3 is required for recognition and regulation of translation initiation of mitochondrial mRNAs and for coordinated assembly of OXPHOS complexes in vivo.

scholarly journals Sequences required for delivery and localization of the ADP/ATP translocator to the mitochondrial inner membrane.

1986 ◽  
Vol 6 (2) ◽  
pp. 626-634 ◽  
Author(s):  
G S Adrian ◽  
M T McCammon ◽  
D L Montgomery ◽  
M G Douglas
Keyword(s):  
Transmembrane Protein ◽  
Nuclear Gene ◽  
Translocator Protein ◽  
Gene Encoding ◽  
Inner Membrane ◽  
Amino Terminal ◽  
Mitochondrial Inner Membrane ◽  
Membrane Anchoring ◽  
High Degree

The ADP/ATP translocator, a transmembrane protein of the mitochondrial inner membrane, is coded in Saccharomyces cerevisiae by the nuclear gene PET9. DNA sequence analysis of the PET9 gene showed that it encoded a protein of 309 amino acids which exhibited a high degree of homology with mitochondrial translocator proteins from other sources. This mitochondrial precursor, in contrast to many others, does not contain a transient presequence which has been shown to direct the posttranslational localization of proteins in the organelle. Gene fusions between the PET9 gene and the gene encoding beta-galactosidase (lacZ) were constructed to define the location of sequences necessary for the mitochondrial delivery of the ADP/ATP translocator protein in vivo. These studies reveal that the information to target the hybrid molecule to the mitochondria is present within the first 115 residues of the protein. In addition, these studies suggest that the "import information" of the amino-terminal region of the ADP/ATP translocator precursor is twofold. In addition to providing targeting function of the precursor to the organelle, these amino-terminal sequences act to prevent membrane-anchoring sequences located between residues 78 and 98 from stopping import at the outer mitochondrial membrane. These results are discussed in light of the function of distinct protein elements at the amino terminus of mitochondrially destined precursors in both organelle delivery and correct membrane localization.

Translational regulation of mitochondrial gene expression by nuclear genes of Saccharomyces cerevisiae

1988 ◽  
Vol 319 (1193) ◽  
pp. 97-105 ◽  
Keyword(s):  
Gene Expression ◽  
Mitochondrial Gene ◽  
Nuclear Gene ◽  
Mitochondrial Genes ◽  
Nuclear Genes ◽  
Mitochondrial Gene Expression ◽  
Wild Type ◽  
Mitochondrial Translation ◽  
Coding Sequence ◽  
Sites Of Action

We describe several yeast nuclear mutations that specifically block expression of the mitochondrial genes encoding cytochrome c oxidase subunits II (COXII) and III (COXIII). These recessive mutations define positive regulators of mitochondrial gene expression that act at the level of translation. Mutations in the nuclear gene PET111 completely block accumulation of COXII, but the COXII mRNA is present in mutant cells at a level approximately one-third of that of the wild type. Mitochondrial suppressors of pet 111 mutations correspond to deletions in mtDNA that result in fusions between the cox II structural gene and other mitochondrial genes. The chimeric mRNAs encoded by these fusions are translated in pet 111 mutants; this translation leads to accumulation of functional COXII. The PET111 protein probably acts directly on cox II translation, because it is located in mitochondria. Translation of the mitochondrially coded mRNA for COXIII requires the action of at least three nuclear genes, PET 494, and a newly discovered gene, provisionally termed PET 55. Both the PET494 and PET54 proteins are located in mitochondria and therefore probably act directly on the mitochondrial translation system. Mutations in all three genes are suppressed in strains that contain chimeric cox III mRNAs with the 5'-untranslated leaders of other mitochondrial transcripts fused to the cox III coding sequence. The products of all three nuclear genes may form a complex and carry out a single function. A direct demonstration that the wild-type nuclear gene products act in the cox III 5'-leader has been obtained by showing that they are all required for translation of apocytochrome b from a novel mRNA consisting of the cox lIl 5'-leader attached to the cytochrome b coding sequence. The site (or sites) of action maps at least 172 bases upstream from the cox lll initiation codon in the 600 base cox III leader. Others have reported evidence which suggests that cox Ill translation is repressed by glucose. Consistently with the possibility that the nuclear genes described here may play a role in modulating mitochondrial gene expression, we have found that PET 494 expression is glucose-repressed.

scholarly journals Ni2+ Transport and Accumulation inRhodospirillum rubrum

1999 ◽  
Vol 181 (15) ◽  
pp. 4554-4560 ◽  
Author(s):  
Richard K. Watt ◽  
Paul W. Ludden
Keyword(s):  
Gene Products ◽  
Wild Type ◽  
Divalent Metal Ions ◽  
Co Dehydrogenase ◽  
Reading Frame ◽  
Carbonyl Cyanide ◽  
Transport Assay ◽  
Fold Excess ◽  
Ni Accumulation

ABSTRACT The cooCTJ gene products are coexpressed with CO-dehydrogenase (CODH) and facilitate in vivo nickel insertion into CODH. A Ni2+ transport assay was used to monitor uptake and accumulation of 63Ni2+ into R. rubrum and to observe the effect of mutations in thecooC, cooT, and cooJ genes on63Ni2+ transport and accumulation. Cells grown either in the presence or absence of CO transported Ni2+with a Km of 19 ± 4 μM and aV max of 310 ± 22 pmol of Ni/min/mg of total protein. Insertional mutations disrupting the reading frame of the cooCTJ genes, either individually or all three genes simultaneously, transported Ni2+ the same as wild-type cells. The nickel specificity for transport was tested by conducting the transport assay in the presence of other divalent metal ions. At a 17-fold excess Mn2+, Mg2+, Ca2+, and Zn2+ showed no inhibition of63Ni2+ transport but Co2+, Cd2+, and Cu2+ inhibited transport 35, 58, and 66%, respectively. Nickel transport was inhibited by cold (50% at 4°C), by protonophores (carbonyl cyanidem-chlorophenylhydrazone, 44%, and 2,4-dinitrophenol, 26%), by sodium azide (25%), and hydroxyl amine (33%). Inhibitors of ATP synthase (N,N′-dicyclohexylcarbodiimide and oligomycin) and incubation of cells in the dark stimulated Ni2+ transport. 63Ni accumulation after 2 h was four times greater in CO-induced cells than in cells not exposed to CO. The CO-stimulated 63Ni2+ accumulation coincided with the appearance of CODH activity in the culture, suggesting that the 63Ni2+ was accumulating in CODH. The cooC, cooT, and cooJgenes are required for the increased 63Ni2+accumulation observed upon CO exposure because cells containing mutations disrupting any or all of these genes accumulated63Ni2+ like cells unexposed to CO.

scholarly journals Yeast nuclear PET127 gene can suppress deletions of the SUV3 or DSS1 genes: an indication of a functional interaction between 3' and 5' ends of mitochondrial mRNAs.

1998 ◽  
Vol 45 (4) ◽  
pp. 935-940 ◽  
Author(s):  
T Wegierski ◽  
A Dmochowska ◽  
A Jabłonowska ◽  
A Dziembowski ◽  
E Bartnik ◽  
...  
Keyword(s):  
Copy Number ◽  
Molecular Level ◽  
Nuclear Gene ◽  
Functional Coupling ◽  
Mitochondrial Rna ◽  
Gene Products ◽  
Mitochondrial Translation ◽  
Functional Interaction ◽  
Negative Phenotype

Saccharomyces cerevisiae nuclear genes SUV3 and DSS1 encode putative RNA helicase and RNase II, respectively, which are subunits of the mitochondrial degradosome (mtEXO): a three-protein complex which has a 3' to 5' exoribonuclease activity and plays a major role in regulating stability of mitochondrial RNA. Lack of either of the two gene products results in a respiratory negative phenotype, while on the molecular level it causes a total block of mitochondrial translation, loss of the in vitro exoribonuclease activity and changes in stability and processing of many mtRNAs. We have found that the yeast nuclear gene PET127 present on a low or high copy number vector can effectively suppress the effects of the SUV3 or DSS1 gene disruptions. Since the product of the PET127 gene is involved in processing of the 5' ends of mitochondrial mRNAs, we suggest that there is a functional coupling between the 5' and 3' ends of mitochondrial mRNAs.

scholarly journals Suppression of a defect in the 5' untranslated leader of mitochondrial COX3 mRNA by a mutation affecting an mRNA-specific translational activator protein.

1993 ◽  
Vol 13 (8) ◽  
pp. 4806-4813 ◽  
Author(s):  
M C Costanzo ◽  
T D Fox
Keyword(s):  
Nuclear Gene ◽  
Gene Products ◽  
Wild Type ◽  
Large Deletions ◽  
Site Of Action ◽  
Genes Encoding ◽  
Cold Sensitive ◽  
Translational Activator ◽  
A Site ◽  
Dominant Suppressor

Translation of the Saccharomyces cerevisiae mitochondrial COX3 mRNA, encoding subunit III of cytochrome c oxidase, specifically requires the action of the nuclear gene products PET54, PET122, and PET494 at a site encoded in the 612-base 5' untranslated leader. To identify more precisely the site of action of the translational activators, we constructed two large deletions of the COX3 mRNA 5' untranslated leader. Both deletions blocked translation without affecting mRNA stability. However, one of the large deletions was able to revert to partial function by a small secondary deletion within the remaining 5' leader sequences. Translation of the resulting mutant (cox3-15) mRNA was still dependent on the nuclear-encoded specific activators but was cold sensitive. We selected revertants of this mitochondrial mutant at low temperature to identify genes encoding proteins that might interact with the COX3 mRNA 5' leader. One such revertant carried a missense mutation in the PET122 gene that was a strong and dominant suppressor of the cold-sensitive defect in the mRNA, indicating that the PET122 protein interacts functionally (possibly directly) with the COX3 mRNA 5' leader. The cox3-15 mutation was not suppressed by overproduction of the wild-type PET122 protein but was very weakly suppressed by overproduction of PET494 and slightly better suppressed by co-overproduction of PET494 and PET122.

scholarly journals A human pathology-related mutation prevents import of an aminoacyl-tRNA synthetase into mitochondria

2011 ◽  
Vol 433 (3) ◽  
pp. 441-446 ◽  
Author(s):  
Marie Messmer ◽  
Catherine Florentz ◽  
Hagen Schwenzer ◽  
Gert C. Scheper ◽  
Marjo S. van der Knaap ◽  
...  
Keyword(s):  
Nuclear Gene ◽  
Trna Synthetase ◽  
Aminoacyl Trna Synthetase ◽  
Mitochondrial Translation ◽  
Gene Coding ◽  
Human Pathology ◽  
Key Enzyme ◽  
Targeting Signal

Mutations in the nuclear gene coding for the mitochondrial aspartyl-tRNA synthetase, a key enzyme for mitochondrial translation, are correlated with leukoencephalopathy. A Ser45 to Gly45 mutation is located in the predicted targeting signal of the protein. We demonstrate in the present study, by in vivo and in vitro approaches, that this pathology-related mutation impairs the import process across mitochondrial membranes.

scholarly journals Multiple Translational Control Sequences in the 5′ Leader of the Chloroplast psbC mRNA Interact With Nuclear Gene Products in Chlamydomonas reinhardtii

Genetics ◽  
2003 ◽  
Vol 163 (3) ◽  
pp. 895-904
Author(s):  
William Zerges ◽  
Andrea H Auchincloss ◽  
Jean-David Rochaix
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Reporter Gene ◽  
Translational Control ◽  
Nuclear Gene ◽  
Gene Products ◽  
Wild Type ◽  
Translation Initiation Region ◽  
Mrna Stabilization ◽  
In The Wild ◽  
Nuclear Loci

Abstract Translation of the chloroplast psbC mRNA in the unicellular eukaryotic alga Chlamydomonas reinhardtii is controlled by interactions between its 547-base 5′ untranslated region and the products of the nuclear loci TBC1, TBC2, and possibly TBC3. In this study, a series of site-directed mutations in this region was generated and the ability of these constructs to drive expression of a reporter gene was assayed in chloroplast transformants that are wild type or mutant at these nuclear loci. Two regions located in the middle of the 5′ leader and near the initiation codon are important for translation. Other deletions still allow for partial expression of the reporter gene in the wild-type background. Regions with target sites for TBC1 and TBC2 were identified by estimating the residual translation activity in the respective mutant backgrounds. TBC1 targets include mostly the central part of the leader and the translation initiation region whereas the only detected TBC2 targets are in the 3′ part. The 5′-most 93 nt of the leader are required for wild-type levels of transcription and/or mRNA stabilization. The results indicate that TBC1 and TBC2 function independently and further support the possibility that TBC1 acts together with TBC3.

scholarly journals ABSENCE OF DETECTABLE MITOCHONDRIAL RECOMBINATION IN PARAMECIUM

Genetics ◽  
1979 ◽  
Vol 93 (4) ◽  
pp. 797-831
Author(s):  
André Adoutte ◽  
Jonathan K Knowles ◽  
Annie Sainsard-Chanet
Keyword(s):  
Antibiotic Resistance ◽  
Large Scale ◽  
Nuclear Gene ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Resistance Mutations ◽  
Mitochondrial Recombination ◽  
Mitochondrial Ribosomes ◽  
Molecular Alterations ◽  
Resistance Markers

ABSTRACT An extensive search for recombination between mitochondrial markers was carried out in Paramecium tetraurelia. Thirty-two combinations, altogether involving 24 different markers, were studied. The markers belonged to the three main categories of mitochondrial mutations presently available in this organism. (a) Spontaneous or UV-induced antibiotic resistance mutations, most probably affecting mitochondrial ribosomes, (b) nitrowguanidine-induced antibiotic resistance markers displaying thermosensitivity or slow growth, enabling easy selection of possible wild-type recombinants, and (c) mitochondrial partial suppressors of a nuclear gene, probably corresponding to molecular alterations distinct from the preceding two categories. In addition, different genetic configurations were analyzed (i e., mutant x mutant, double-mutant x wild-type, etc.).——None of the combinations yielded any evidence for the occurrence of recombined genomes despite the fact that: (1) all of them were studied on a large scale involving the screening of at least several thousand mitochondrial genomes (often several millions), (2) in many of them the detection level was sufficiently high to enable the isolation of spontaneous mutants in control cells, and (3) in several of them, reconstitution experiments carried out in parallel show that the conditions were fully adequate to detect recombinant genotypes. The results are in marked contrast with those obtained on the few other organisms in which mitochondrial recombination has been studied, particularly Saccharomyces cerevisiae, in which mitochondrial recombination is intense.——The most likely basis for the various manifestations of mitochondrial genetic autonomy in Paramecium, described in this as well as in previous publications, is that the chondriome of this organism is made up of thousands of structurally discrete, noninteracting units.

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