Expression of Saccharomyces cerevisiae Sdh3p and Sdh4p Paralogs Results in Catalytically Active Succinate Dehydrogenase Isoenzymes

Hsieh

Antioxidants & Redox Signaling

et al. 2015

Aims: Mitochondrial succinate dehydrogenase (SDH) is an essential complex of the electron transport chain and tricarboxylic acid cycle. Mutations in the human SDH subunit D frequently lead to paraganglioma (PGL), but the mechanistic consequences of the majority of SDHD polymorphisms have yet to be unraveled. In addition to the originally discovered yeast SDHD subunit Sdh4, a conserved homolog, Shh4, has recently been identified in budding yeast. To assess the pathogenic significance of SDHD mutations in PGL patients, we performed functional studies in yeast. Results: SDHD protein expression was reduced in SDHD-related carotid body tumor tissues. A BLAST search of SDHD to the yeast protein database revealed a novel protein, Shh4, that may have a function similar to human SDHD and yeast Sdh4. The missense SDHD mutations identified in PGL patients were created in Sdh4 and Shh4, and, surprisingly, a severe respiratory incompetence and reduced expression of the mutant protein was observed in the sdh4D strain expressing shh4. Although shh4D cells showed no respiratory-deficient phenotypes, deletion of SHH4 in sdh4D cells further abolished mitochondrial function. Remarkably, sdh4D shh4D strains exhibited increased reactive oxygen species (ROS) production, nuclear DNA instability, mtDNA mutability, and decreased chronological lifespan. Innovation and Conclusion: SDHD mutations are associated with protein and nuclear and mitochondrial genomic instability and increase ROS production in our yeast model. These findings reinforce our understanding of the mechanisms underlying PGL tumorigenesis and point to the yeast Shh4 as a good model to investigate the possible pathogenic relevance of SDHD in PGL polymorphisms. Antioxid. Redox Signal. 22, 587-602.

Section: Figsupporting

confidence: 92%

“…2B). In addition to the high conservation between Shh4 and Sdh4 (46% of identity and 0.81 of genetic distance), a previous study found that Shh4 can form a respiration competent SDH isoenzyme with Sdh3 in sdh4D cells (64). Together, these results indicate that Shh4 have a function similar to function as human SDHD and yeast Sdh4.…”

Section: Innovationmentioning

confidence: 61%

Instability of Succinate Dehydrogenase in SDHD Polymorphism Connects Reactive Oxygen Species Production to Nuclear and Mitochondrial Genomic Mutations in Yeast

Hsieh

Antioxidants & Redox Signaling

et al. 2015

“…This could have subtle effects on growth phases during pathogenicity and may carry an advantage leading to their maintenance within populations, particularly if the gene is under developmental regulation and leads to a SQR enzyme of differing efficiency as found in parasitic nematodes (47, 48) or plants (49). In yeast, one paralog of the SDHC subunit and one paralog of the SDHD subunit were shown to lead to hybrid functional SQR enzymes which, although less active, may play an adaptive role in restrictive environmental conditions (50). Similarly to mutants of the classical SDHC and SDHD subunits, the hybrid SQRs conferred very distinct “metabotypes” which also correlated with different growth yield (50, 51).…”

Section: Discussionmentioning

confidence: 99%

“…In yeast, one paralog of the SDHC subunit and one paralog of the SDHD subunit were shown to lead to hybrid functional SQR enzymes which, although less active, may play an adaptive role in restrictive environmental conditions (50). Similarly to mutants of the classical SDHC and SDHD subunits, the hybrid SQRs conferred very distinct “metabotypes” which also correlated with different growth yield (50, 51). Interestingly, the yeast SDHC paralog may also carry additional function(s) as the protein was found in a subcomplex with Tim18p as part of the TIM22 inner membrane translocase (52).…”

Section: Discussionmentioning

confidence: 99%

A dispensable paralog of succinate dehydrogenase subunit C mediates standing resistance towards a subclass of SDHI fungicides inZymoseptoria tritici

Steinhauer

Salat

Frey

et al. 2019

Preprint

34Succinate dehydrogenase inhibitor (SDHI) fungicides are widely used for the control of a 35 broad range of fungal diseases. This has been the most rapidly expanding fungicide group in 36 terms of new molecules discovered and introduced for agricultural use over the past fifteen 37 years. A particular pattern of differential sensitivity (resistance) to a subclass of chemically-38 related SDHIs (SHA-SDHIs) was observed in naïve Zymoseptoria tritici populations. Class 39 specific SHA-SDHI resistance was confirmed at the enzyme level but did not correlate with 40 the genotypes of the succinate dehydrogenase (SDH) encoding genes. Mapping and 41 characterization of the genetic factor responsible for standing SHA-SDHI resistance in natural 42 field isolates identified a gene (alt-SDHC) encoding a paralog of the C subunit of succinate 43 dehydrogenase. This paralog was not present within our sensitive reference isolates and found 44 at variable frequencies within Z. tritici populations. Using reverse genetics, we showed that 45 alt-SDHC associates with the three other SDH subunits leading to a fully functional enzyme 46 and that a unique Qp-site residue within the alt-SDHC protein confers SHA-SDHI resistance. 47 Enzymatic assays, computational modelling and docking simulations for the two types of 48 SQR enzymes (alt-SDHC, SDHC) enabled us to describe protein-inhibitor interactions at an 49 atomistic level and to propose rational explanations for differential potency and resistance 50 across SHA-SDHIs. European Z. tritici populations displayed a presence (20-30%) / absence 51 polymorphism of alt-SDHC, as well as differences in alt-SDHC expression levels and splicing 52 efficiency. These polymorphisms have a strong impact on SHA-SDHI resistance phenotypes. 53Characterization of the alt-SDHC promoter in European Z. tritici populations suggest that 54 transposon insertions are associated with the strongest resistance phenotypes. These results 55 establish that a dispensable paralogous gene determines SHA-SDHIs fungicide resistance in 56 natural populations of Z. tritici. This study paves the way to an increased awareness of the 3 57 role of fungicidal target paralogs in resistance to fungicides and demonstrates the paramount 58 importance of population genomics in fungicide discovery. 59 Author Summary 60Zymoseptoria tritici is the causal agent of Septoria tritici leaf blotch (STB) of wheat, the most 61 devastating disease for cereal production in Europe. Multiple succinate dehydrogenase 62 inhibitor (SDHI) fungicides have been developed and introduced for the control of STB. We 63 report the discovery and detailed characterization of a paralog of the C subunit of the SDH 64 enzyme conferring standing resistance towards a particular chemical subclass of the SDHIs. 65The resistance gene is characterized by its presence/absence, expression and splicing 66 polymorphisms which in turn affect resistance levels. The identified mechanism influenced 67 the chemical optimization phase which led to the discovery of pydiflu...

“…Compared with the two chromatographic platforms, NMR-based analysis requires simple and easy sample preparation, which is beneficial for minimizing changes in the chemical composition and reducing the loss of minor components (8,9); simultaneously monitors various organic chemical species (10,11); and shows the potential for efficient high-throughput screening (12). Therefore, the application of an NMR-based platform in metabolomics has been widely reported for studies with a variety of microorganisms, including studies of metabolic flux changes in Escherichia coli during heat (13) and superoxide (14) stresses and the role of genes in Saccharomyces cerevisiae (15,16). Highthroughput NMR-based metabolomics analysis facilitates the characterization of large numbers of individuals.…”

mentioning

confidence: 99%

Dynamic Metabolic and Transcriptional Profiling of Rhodococcus sp. Strain YYL during the Degradation of Tetrahydrofuran

Yao

Lü

et al. 2014

Appl Environ Microbiol

cAlthough tetrahydrofuran-degrading Rhodococcus sp. strain YYL possesses tetrahydrofuran (THF) degradation genes similar to those of other tetrahydrofuran-degrading bacteria, a much higher degradation efficiency has been observed in strain YYL. In this study, nuclear magnetic resonance (NMR)-based metabolomics analyses were performed to explore the metabolic profiling response of strain YYL to exposure to THF. Exposure to THF slightly influenced the metabolome of strain YYL when yeast extract was present in the medium. The metabolic profile of strain YYL over time was also investigated using THF as the sole carbon source to identify the metabolites associated with high-efficiency THF degradation. Lactate, alanine, glutarate, glutamate, glutamine, succinate, lysine, trehalose, trimethylamine-N-oxide (TMAO), NAD ؉ , and CTP were significantly altered over time in strain YYL grown in 20 mM THF. Real-time quantitative PCR (RT-qPCR) revealed changes in the transcriptional expression levels of 15 genes involved in THF degradation, suggesting that strain YYL could accumulate several disturbances in osmoregulation (trehalose, glutamate, glutamine, etc.), with reduced glycolysis levels, an accelerated tricarboxylic acid cycle, and enhanced protein synthesis. The findings obtained through 1 H NMR metabolomics analyses and the transcriptional expression of the corresponding genes are complementary for exploring the dynamic metabolic profile in organisms.