GmMYB176 Interactome and Regulation of Isoflavonoid Biosynthesis in Soybean

MYB transcription factors are one of the largest transcription factor families characterized in plants. They are classified into four types: R1 MYB, R2R3 MYB, R3 MYB and R4 MYB. GmMYB176 is an R1MYB transcription factor that regulates Chalcone synthase (CHS8) gene expression and isoflavonoid biosynthesis in soybean. Silencing of GmMYB176 suppressed the expression of the GmCHS8 gene and reduced the accumulation of isoflavonoids in soybean hairy roots. However, overexpression of GmMYB176 does not alter either GmCHS8 gene expression or isoflavonoid levels suggesting that GmMYB176 alone is not sufficient for GmCHS8 gene regulation. I hypothesized that GmMYB176 acts cooperatively with another factor(s) for the regulation of GmCHS8 gene expression and it may also regulate other isoflavonoid biosynthetic genes in soybean. The objective of this research was to identify the GmMYB176 interactome for GmCHS8 gene regulation and elucidate the role of GmMYB176 in isoflavonoid biosynthesis in soybean. GmMYB176 interacting proteins were identified using two translational fusion baits (GmMYB176-YFP and YFP-GmMYB176) by co-immunoprecipitation, followed by liquid chromatography-tandem mass spectrometry. The interaction of selected candidates with GmMYB176 was validated in planta and their DNA binding activities determined. GmMYB176 may form a transcriptional complex with Gm04bZIP and/or Gm05bZIP for the regulation of GmCHS8 gene expression. RNA-seq and metabolomics analyses of soybean hairy roots in which GmMYB176 was either silenced or over-expressed revealed that GmMYB176 regulates multiple genes in the isoflavonoid biosynthesis pathway, affecting the production of metabolites in phenylpropanoid pathway such as phenylalanine, liquiritigenin, daidzin, genistin, glycitein, and glyceollin. The knowledge and information generated on the role of GmMYB176 in the regulation of isoflavonoid biosynthesis will allow genetic manipulation of isoflavonoid level in soybean and/or introduce isoflavonoid pathway in non-legumes

GmMYB176 Regulates Multiple Steps in Isoflavonoid Biosynthesis in Soybean

Isoflavonoids are a group of plant natural compounds synthesized almost exclusively by legumes, and are abundant in soybean seeds and roots. They play important roles in plant-microbial interactions and the induction of nod gene expression in Rhizobia that form nitrogen-fixing nodules on soybean roots. Isoflavonoids also contribute to the positive health effects associated with soybean consumption by humans and animals. An R1 MYB transcription factor GmMYB176 regulates isoflavonoid biosynthesis by activating chalcone synthase (CHS) 8 gene expression in soybean. Using a combination of transcriptomic and metabolomic analyses of GmMYB176-RNAi silenced (GmMYB176-Si), GmMYB176-overexpressed (GmMYB176-OE), and control soybean hairy roots, we identified a total of 33 differentially expressed genes (DEGs) and 995 differentially produced metabolite features (DPMF) in GmMYB176-Si hairy roots, and 5727 DEGs and 149 DPMFs in GmMYB176-OE hairy roots. By a targeted approach, 25 isoflavonoid biosynthetic genes and 6 metabolites were identified as differentially regulated in GmMYB176-OE and GmMYB176-Si soybean hairy roots. Taken together, our results demonstrate the complexity of isoflavonoid biosynthesis in soybean roots and suggest that a coordinated expression of pathway genes, substrate flux and product threshold level may contribute to the dynamic of the pathway regulation

Splicing is an alternate oncogenic pathway activation mechanism in glioma

High-grade diffuse glioma (HGG) is the leading cause of brain tumour death. While the genetic drivers of HGG have been well described, targeting these has thus far had little impact on survival suggesting other mechanisms are at play. Here we interrogate the alternative splicing landscape of pediatric and adult HGG through multi-omic analyses, uncovering an increased splicing burden compared with normal brain. The rate of recurrent alternative splicing in cancer drivers exceeds their mutation rate, a pattern that is recapitulated in pan-cancer analyses, and is associated with worse prognosis in HGG. We investigate potential oncogenicity by interrogating cancer pathways affected by alternative splicing in HGG; spliced cancer drivers include members of the RAS/MAPK pathway. RAS suppressor neurofibromin 1 is differentially spliced to a less active isoform in >80% of HGG downstream from REST upregulation, activating the RAS/MAPK pathway and reducing glioblastoma patient survival. Overall, our results identify non-mutagenic mechanisms by which cancers activate oncogenic pathways which need to accounted for in personalized medicine approaches

Genome-wide identification and localization of chalcone synthase family in soybean (Glycine max [L]Merr)

Abstract Background Soybean is a paleopolyploid that has undergone two whole genome duplication events. Gene duplication is a type of genomic change that can lead to novel functions of pre-existing genes. Chalcone synthase (CHS) is the plant-specific type III polyketide synthase that catalyzes the first committed step in (iso)flavonoid biosynthesis in plants. Results Here we performed a genome-wide search of CHS genes in soybean, and identified 21 GmCHS loci containing 14 unique GmCHS (GmCHS1-GmCHS14) that included 5 newly identified GmCHSs (GmCHS10-GmCHS14). Furthermore, 3 copies of GmCHS3 and 2 copies of GmCHS4 were found in soybean. Analysis of gene structure of GmCHSs revealed the presence of a single intron in protein-coding regions except for GmCHS12 that contained 3 introns. Even though GmCHS genes are located on 8 different chromosomes, a large number of these genes are present on chromosome 8 where they form 3 distinct clusters. Expression analysis of GmCHS genes revealed tissue-specific expression pattern, and that some GmCHS isoforms localize in the cytoplasm and the nucleus while other isoforms are restricted to cytoplasm only. Conclusion Overall, we have identified 21 GmCHS loci with 14 unique GmCHS genes in the soybean genome. Their gene structures and genomic organization together with the spatio-temporal expression and protein localization suggest their importance in the production of downstream metabolites such as (iso)flavonoids and their derived phytoalexins

Oncohistone interactome profiling uncovers contrasting oncogenic mechanisms and identifies potential therapeutic targets in high grade glioma.

International audienceHistone H3 mutations at amino acids 27 (H3K27M) and 34 (H3G34R) are recurrent drivers of pediatric-type high-grade glioma (pHGG). H3K27M mutations lead to global disruption of H3K27me3 through dominant negative PRC2 inhibition, while H3G34R mutations lead to local losses of H3K36me3 through inhibition of SETD2. However, their broader oncogenic mechanisms remain unclear. We characterized the H3.1K27M, H3.3K27M and H3.3G34R interactomes, finding that H3K27M is associated with epigenetic and transcription factor changes; in contrast H3G34R removes a break on cryptic transcription, limits DNA methyltransferase access, and alters mitochondrial metabolism. All 3 mutants had altered interactions with DNA repair proteins and H3K9 methyltransferases. H3K9me3 was reduced in H3K27M-containing nucleosomes, and cis-H3K9 methylation was required for H3K27M to exert its effect on global H3K27me3. H3K9 methyltransferase inhibition was lethal to H3.1K27M, H3.3K27M and H3.3G34R pHGG cells, underscoring the importance of H3K9 methylation for oncohistone-mutant gliomas and suggesting it as an attractive therapeutic target

Metaproteomics Applied to Activated Sludge for Industrial Wastewater Treatment Revealed a Dominant Methylotrophic Metabolism of Hyphomicrobium zavarzinii

In biological wastewater treatments, microbial populations of the so-called activated sludge work together in the abatement of pollutants. In this work, the metabolic behavior of the biomass of a lab-scale plant treating industrial pharmaceutical wastewater was investigated through a metaproteomic approach. The complete treatment process included a membrane biological reactor (MBR) coupled with an advanced oxidation process (AOP) for partial breakdown of non-biodegradable molecules. Proteins from biomass samples collected pre- and post-AOP application were investigated by two-dimensional gel electrophoresis (2DE), mass spectrometry (MS), and finally identified by database search. Results showed that most proteins remained constant between pre- and post-AOP. Methanol dehydrogenase (MDH) belonging to Hyphomicrobium zavarzinii appeared as the most constantly expressed protein in the studied consortium. Other identified proteins belonging to Hyphomicrobium spp. revealed a predominant methylotrophic metabolism, and H. zavarzinii appeared as a key actor in the studied microbial community