The maize NCS2 abnormal growth mutant has a chimeric nad4-nad7 mitochondrial gene and is associated with reduced complex I function.

Abstract The molecular basis of the maternally inherited, heteroplasmic NCS2 mutant of maize was investigated. Analysis of the NCS2 mtDNA showed that it closely resembles the progenitor cmsT mitochondrial genome, except that the mutant genome contains a fused nad4-nad7 gene and is deleted for the small fourth exon of nad4. The rearrangement has occurred at a 16-bp repeat present in the third intron of the nad4 gene and in the second intron of the nad7 gene. Transcripts containing exon 4 of the nad4 gene are greatly reduced in mtRNA preparations from heteroplasmic NCS2 plants; larger transcripts are associated with the first three nad4 exons. Identical 5' ends of the nad4 transcripts have been mapped 396 and 247 bp upstream of the start codon in mtRNAs from both NCS2 and related non-NCS plants. The putative transcription termination signal of nad4 is deleted in mutant DNA, resulting in the production of the unique longer transcripts. The complex transcript pattern associated with nad7 is also altered in the mutant. Both nad4 and nad7 encode subunits of complex I (NADH dehydrogenase) of the mitochondrial electron transfer chain. Oxygen uptake experiments show that the functioning of complex I is specifically reduced in mitochondria isolated from NCS2 mutant plants.

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TAT-Conjugated NDUFS8 Can Be Transduced into Mitochondria in a Membrane-Potential-Independent Manner and Rescue Complex I Deficiency

International Journal of Molecular Sciences ◽

10.3390/ijms22126524 ◽

2021 ◽

Vol 22 (12) ◽

pp. 6524

Author(s):

Bo-Yu Lin ◽

Gui-Teng Zheng ◽

Kai-Wen Teng ◽

Juan-Yu Chang ◽

Chao-Chang Lee ◽

...

Keyword(s):

Membrane Potential ◽

Fusion Proteins ◽

Complex I ◽

Nadh Dehydrogenase ◽

Leigh Syndrome ◽

Protein Transduction ◽

Independent Manner ◽

Complex I Deficiency ◽

Transactivator Of Transcription ◽

Hiv 1

NADH dehydrogenase (ubiquinone) Fe-S protein 8 (NDUFS8) is a nuclear-encoded core subunit of human mitochondrial complex I. Defects in NDUFS8 are associated with Leigh syndrome and encephalomyopathy. Cell-penetrating peptide derived from the HIV-1 transactivator of transcription protein (TAT) has been successfully applied as a carrier to bring fusion proteins into cells without compromising the biological function of the cargoes. In this study, we developed a TAT-mediated protein transduction system to rescue complex I deficiency caused by NDUFS8 defects. Two fusion proteins (TAT-NDUFS8 and NDUFS8-TAT) were exogenously expressed and purified from Escherichia coli for transduction of human cells. In addition, similar constructs were generated and used in transfection studies for comparison. The results showed that both exogenous TAT-NDUFS8 and NDUFS8-TAT were delivered into mitochondria and correctly processed. Interestingly, the mitochondrial import of TAT-containing NDUFS8 was independent of mitochondrial membrane potential. Treatment with TAT-NDUFS8 not only significantly improved the assembly of complex I in an NDUFS8-deficient cell line, but also partially rescued complex I functions both in the in-gel activity assay and the oxygen consumption assay. Our current findings suggest the considerable potential of applying the TAT-mediated protein transduction system for treatment of complex I deficiency.

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Molecular Gene Therapy: Overexpression of the Alternative NADH Dehydrogenase NDI1 Restores Overall Physiology in a Fungal Model of Respiratory Complex I Deficiency

Journal of Molecular Biology ◽

10.1016/j.jmb.2010.04.015 ◽

2010 ◽

Vol 399 (1) ◽

pp. 31-40 ◽

Cited By ~ 18

Author(s):

Marc F.P.M. Maas ◽

Carole H. Sellem ◽

Frank Krause ◽

Norbert A. Dencher ◽

Annie Sainsard-Chanet

Keyword(s):

Gene Therapy ◽

Complex I ◽

Nadh Dehydrogenase ◽

Respiratory Complex ◽

Complex I Deficiency ◽

Respiratory Complex I

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Physiological relevance, localization and substrate specificity of the alternative (type II) mitochondrial NADH dehydrogenases of Ogataea parapolymorpha

10.1101/2021.04.28.441406 ◽

2021 ◽

Author(s):

Hannes Juergens ◽

Álvaro Mielgo-Gómez ◽

Albert Godoy-Hernández ◽

Jolanda ter Horst ◽

Janine M. Nijenhuis ◽

...

Keyword(s):

Substrate Specificity ◽

Respiratory Chain ◽

Complex I ◽

Nadh Dehydrogenase ◽

Physiological Role ◽

Proton Pumping ◽

Type Ii ◽

Respiratory Chains ◽

Alternative Type ◽

Nadh Dehydrogenases

AbstractMitochondria from Ogataea parapolymorpha harbor a branched electron-transport chain containing a proton-pumping Complex I NADH dehydrogenase and three alternative (type II) NADH dehydrogenases (NDH2s). To investigate the physiological role, localization and substrate specificity of these enzymes, growth of various NADH dehydrogenase mutants was quantitatively characterized in shake-flask and chemostat cultures, followed by oxygen-uptake experiments with isolated mitochondria. Furthermore, NAD(P)H:quinone oxidoreduction of the three NDH2s were individually assessed. Our findings show that the O. parapolymorpha respiratory chain contains an internal NADH-accepting NDH2 (Ndh2-1/OpNdi1), at least one external NAD(P)H-accepting enzyme and likely additional mechanisms for respiration-linked oxidation of cytosolic NADH. Metabolic regulation appears to prevent competition between OpNdi1 and Complex I for mitochondrial NADH. With the exception of OpNdi1, the respiratory chain of O. parapolymorpha exhibits metabolic redundancy and tolerates deletion of multiple NADH-dehydrogenase genes without compromising fully respiratory metabolism.ImportanceTo achieve high productivity and yields in microbial bioprocesses, efficient use of the energy substrate is essential. Organisms with branched respiratory chains can respire via the energy-efficient proton-pumping Complex I, or make use of alternative NADH dehydrogenases (NDH2s). The yeast Ogataea parapolymorpha contains three uncharacterized, putative NDH2s which were investigated in this work. We show that O. parapolymorpha contains at least one ‘internal’ NDH2, which provides an alternative to Complex I for mitochondrial NADH oxidation, albeit at a lower efficiency. The use of this NDH2 appeared to be limited to carbon excess conditions and the O. parapolymorpha respiratory chain tolerated multiple deletions without compromising respiratory metabolism, highlighting opportunities for metabolic (redox) engineering. By providing a more comprehensive understanding of the physiological role of NDH2s, including insights into their metabolic capacity, orientation and substrate specificity this study also extends our fundamental understanding of respiration in organisms with branched respiratory chains.

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The mitochondrial AAA protease FTSH3 regulates Complex I abundance by promoting its disassembly

Plant Physiology ◽

10.1093/plphys/kiab074 ◽

2021 ◽

Author(s):

Aneta Ivanova ◽

Abi S Ghifari ◽

Oliver Berkowitz ◽

James Whelan ◽

Monika W Murcha

Keyword(s):

Complex I ◽

Nadh Dehydrogenase ◽

Slow Growth ◽

Nadh:Ubiquinone Oxidoreductase ◽

Temperature Sensitive ◽

Wild Type ◽

Forward Genetic Screen ◽

Slow Growth Rate ◽

Partial Restoration ◽

Screen Approach

Abstract ATP is generated in mitochondria by oxidative phosphorylation. Complex I (NADH:ubiquinone oxidoreductase or NADH dehydrogenase) is the first multisubunit protein complex of this pathway, oxidising NADH and transferring electrons to the ubiquinone pool. Typically Complex I mutants display a slow growth rate compared to wild-type plants. Here, using a forward genetic screen approach for restored growth of a Complex I mutant, we have identified the mitochondrial ATP dependent metalloprotease, Filamentous Temperature Sensitive H 3 (FTSH3), as a factor that is required for the disassembly of Complex I. An ethyl methanesulfonate-induced mutation in FTSH3, named rmb1 (restoration of mitochondrial biogenesis 1), restored Complex I abundance and plant growth. Complementation could be achieved with FTSH3 lacking proteolytic activity, suggesting the unfoldase function of FTSH3 has a role in Complex I disassembly. The introduction of the rmb1 to an additional, independent, and extensively characterised Complex I mutant, ndufs4, resulted in similar increases to Complex I abundance and a partial restoration of growth. These results show that disassembly or degradation of Complex I plays a role in determining its steady-state abundance and thus turnover may vary under different conditions.

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Leishmania type II dehydrogenase is essential for parasite viability irrespective of the presence of an active complex I

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2103803118 ◽

2021 ◽

Vol 118 (42) ◽

pp. e2103803118

Author(s):

Margarida Duarte ◽

Cleide Ferreira ◽

Gurleen Kaur Khandpur ◽

Tamara Flohr ◽

Jannik Zimmermann ◽

...

Keyword(s):

Complex I ◽

Nadh Dehydrogenase ◽

Leishmania Major ◽

Proton Translocation ◽

Protozoan Parasite ◽

Type I ◽

Type Ii ◽

Active Complex ◽

Mitochondrial Inner Membrane ◽

Candidate Target

Type II NADH dehydrogenases (NDH2) are monotopic enzymes present in the external or internal face of the mitochondrial inner membrane that contribute to NADH/NAD+ balance by conveying electrons from NADH to ubiquinone without coupled proton translocation. Herein, we characterize the product of a gene present in all species of the human protozoan parasite Leishmania as a bona fide, matrix-oriented, type II NADH dehydrogenase. Within mitochondria, this respiratory activity concurs with that of type I NADH dehydrogenase (complex I) in some Leishmania species but not others. To query the significance of NDH2 in parasite physiology, we attempted its genetic disruption in two parasite species, exhibiting a silent (Leishmania infantum, Li) and a fully operational (Leishmania major, Lm) complex I. Strikingly, this analysis revealed that NDH2 abrogation is not tolerated by Leishmania, not even by complex I–expressing Lm species. Conversely, complex I is dispensable in both species, provided that NDH2 is sufficiently expressed. That a type II dehydrogenase is essential even in the presence of an active complex I places Leishmania NADH metabolism into an entirely unique perspective and suggests unexplored functions for NDH2 that span beyond its complex I–overlapping activities. Notably, by showing that the essential character of NDH2 extends to the disease-causing stage of Leishmania, we genetically validate NDH2—an enzyme without a counterpart in mammals—as a candidate target for leishmanicidal drugs.

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Electron microscopic analysis of the peripheral and membrane parts of mitochondrial NADH dehydrogenase (Complex I)

Journal of Molecular Biology ◽

10.1016/0022-2836(91)80190-6 ◽

1991 ◽

Vol 221 (3) ◽

pp. 1027-1043 ◽

Cited By ~ 133

Author(s):

Götz Hofhaus ◽

Hanns Weiss ◽

Kevin Leonard

Keyword(s):

Complex I ◽

Nadh Dehydrogenase ◽

Microscopic Analysis ◽

Electron Microscopic Analysis ◽

Electron Microscopic ◽

Dehydrogenase Complex

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Systematics and Evolution in the Tityrinae (Passeriformes: Tyrannoidea)

The Auk ◽

10.1093/auk/124.4.1317 ◽

2007 ◽

Vol 124 (4) ◽

pp. 1317-1329 ◽

Cited By ~ 5

Author(s):

Brian R. Barber ◽

Nathan H. Rice

Keyword(s):

Bayesian Methods ◽

Nadh Dehydrogenase ◽

Gene Sequence ◽

Sequence Data ◽

Mitochondrial Gene ◽

Nadh Dehydrogenase Subunit 2 ◽

Family Level ◽

System Data ◽

Multiple Species ◽

Character Mapping

Abstract We tested the monophyly and determined the phylogenetic relationships of the seven genera (Laniisoma, Laniocera, Iodopleura, Pachyramphus, Schiffornis, Tityra, and Xenopsaris) and 27 of the 31 recognized species of the subfamily Tityrinae using complete gene sequence data from the mitochondrial gene NADH dehydrogenase subunit 2. Monophyly of all seven genera was recovered using both weighted parsimony and Bayesian methods. Intergeneric relationships were nearly identical between the two methods and are largely in concordance with previous studies. Both analyses recovered two basal clades within the Tityrinae: one clade contained Schiffornis, Laniocera, and Laniisoma; the other clade consisted of Iodopleura, Tityra, Xenopsaris, and Pachyramphus. All genera in the Tityrinae that contained multiple species were monophyletic and are concordant with current taxonomy. We present the first phylogeny for Pachyramphus and suggest that Platypsaris is not valid. Character mapping of morphological, nest-construction, and breeding-system data on our phylogeny suggest conservative evolution of most characters. We recommend elevating the Tityrinae to family level. Sistemática y Evolución de los Tityrinae (Passeriformes: Tyrannoidea)

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