scholarly journals Rice FLOURY SHRUNKEN ENDOSPERM 5 Encodes a Putative Plant Organelle RNA Recognition Protein that Is Required for cis-Splicing of Mitochondrial nad4 Intron 1

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Liang Wang ◽  
Wenwei Zhang ◽  
Shijia Liu ◽  
Yunlu Tian ◽  
Xi Liu ◽  
...  
Keyword(s):  
Complex I ◽  
Nadh Dehydrogenase ◽  
Higher Plants ◽  
Splicing Factor ◽  
Rna Recognition ◽  
Rice Mutant ◽  
Intron 1 ◽  
Recognition Protein ◽  
Essential Subunit ◽  
Two Hybrid

Abstract Background The sequences of several important mitochondrion-encoded genes involved in respiration in higher plants are interrupted by introns. Many nuclear-encoded factors are involved in splicing these introns, but the mechanisms underlying this splicing remain unknown. Results We isolated and characterized a rice mutant named floury shrunken endosperm 5 (fse5). In addition to having floury shrunken endosperm, the fse5 seeds either failed to germinate or produced seedlings which grew slowly and died ultimately. Fse5 encodes a putative plant organelle RNA recognition (PORR) protein targeted to mitochondria. Mutation of Fse5 hindered the splicing of the first intron of nad4, which encodes an essential subunit of mitochondrial NADH dehydrogenase complex I. The assembly and NADH dehydrogenase activity of complex I were subsequently disrupted by this mutation, and the structure of the mitochondria was abnormal in the fse5 mutant. The FSE5 protein was shown to interact with mitochondrial intron splicing factor 68 (MISF68), which is also a splicing factor for nad4 intron 1 identified previously via yeast two-hybrid (Y2H) assays. Conclusion Fse5 which encodes a PORR domain-containing protein, is essential for the splicing of nad4 intron 1, and loss of Fse5 function affects seed development and seedling growth.

scholarly journals Rice Floury Shrunken Endosperm5 encodes a putative plant organelle RNA recognition protein that is required for cis-splicing of mitochondrial nad4 intron 1

2020 ◽  
Author(s):  
Liang Wang ◽  
Wenwei Zhang ◽  
Shijia Liu ◽  
Yunlu Tian ◽  
Xi Liu ◽  
...  
Keyword(s):  
Complex I ◽  
Nadh Dehydrogenase ◽  
Higher Plants ◽  
Splicing Factor ◽  
Rna Recognition ◽  
Loss Of Function ◽  
Rice Mutant ◽  
Intron 1 ◽  
Recognition Protein ◽  
Underlying Mechanisms

Abstract Background: Some important mitochondrial-encoded genes for respiration in higher plants are interrupted by introns. Many nuclear-encoded factors are involved in the splicing of these introns, but the underlying mechanisms remain to be deciphered.Results: Here, we isolated and characterized a rice mutant named floury shrunken endosperm5 (fse5). In addition to floury shrunken endosperm seeds with mutant phenotype either failed to germinate or produced retarded lethal seedlings. The Fse5 encodes a putative plant organelle RNA recognition (PORR) protein targeted to mitochondria. Mutation of Fse5 hindered splicing of the first intron of nad4, that encodes an essential subunit of mitochondrial NADH dehydrogenase Complex I. The assembly and NADH dehydrogenase activity of Complex I were disrupted and the structure of the mitochondria was abnormal in the fse5 mutant. FSE5 protein was shown to interact with Mitochondrial Intron Splicing Factor 68 (MISF68), which is also a splicing factor for nad4 intron 1 identified previously in a yeast two-hybrid assay.Conclusion: Fse5 encoding a PORR protein is essential for splicing of nad4 intron 1, and loss of function affects seed development and seedling growth.

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

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.

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

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.

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

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.

Specific inhibition of transcriptional activity of the constitutive androstane receptor (CAR) by the splicing factor SF3a3

2008 ◽  
Vol 389 (10) ◽  
Author(s):  
Hye Jin Yun ◽  
Jungsun Kwon ◽  
Wongi Seol
Keyword(s):  
Transcriptional Activity ◽  
Constitutive Androstane Receptor ◽  
Splicing Factor ◽  
Yeast Two Hybrid ◽  
Interacting Protein ◽  
Functional Studies ◽  
Reporter Activity ◽  
Inhibitory Function ◽  
Two Hybrid ◽  
Hybrid Screening

Abstract The constitutive androstane receptor (CAR) is a member of the nuclear receptor superfamily and plays an important role in the degradation of xenobiotics in the liver. Using yeast two-hybrid screening, we identified SF3a3, a 60-kDa subunit of the splicing factor 3a complex, as a specific CAR-interacting protein. We further confirmed their interaction by both co-immunoprecipitation and GST pull-down assay. Functional studies showed that overexpression of SF3a3 inhibited the reporter activity driven by a promoter containing CAR binding sequences by up to 50%, whereas reduced expression of SF3a3 activated the same reporter activity by approximately three-fold. The inhibitory function of SF3a3 is independent of the presence of TCPOBOP, a CAR ligand. These data suggest that SF3a3 functions as a co-repressor of CAR transcriptional activity, in addition to its canonical function.

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

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.

scholarly journals A Silent Exonic Mutation in a Rice Integrin-α FG-GAP Repeat-Containing Gene Causes Male-Sterility by Affecting mRNA Splicing

2020 ◽  
Vol 21 (6) ◽  
pp. 2018 ◽  
Author(s):  
Ting Zou ◽  
Dan Zhou ◽  
Wenjie Li ◽  
Guoqiang Yuan ◽  
Yang Tao ◽  
...  
Keyword(s):  
Pollen Development ◽  
Molecular Mapping ◽  
Higher Plants ◽  
Donor Site ◽  
Splice Junction ◽  
Splice Donor Site ◽  
Terrestrial Plants ◽  
Male Sterile ◽  
Intron Splice ◽  
Rice Mutant

Pollen development plays crucial roles in the life cycle of higher plants. Here we characterized a rice mutant with complete male-sterile phenotype, pollen-less 1 (pl1). pl1 exhibited smaller anthers with arrested pollen development, absent Ubisch bodies, necrosis-like tapetal hypertrophy, and smooth anther cuticular surface. Molecular mapping revealed a synonymous mutation in the fourth exon of PL1 co-segregated with the mutant phenotype. This mutation disrupts the exon-intron splice junction in PL1, generating aberrant mRNA species and truncated proteins. PL1 is highly expressed in the tapetal cells of developing anther, and its protein is co-localized with plasma membrane (PM) and endoplasmic reticulum (ER) signal. PL1 encodes an integrin-α FG-GAP repeat-containing protein, which has seven β-sheets and putative Ca2+-binding motifs and is broadly conserved in terrestrial plants. Our findings therefore provide insights into both the role of integrin-α FG-GAP repeat-containing protein in rice male fertility and the influence of exonic mutation on intronic splice donor site selection.

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