Biology subjects

Piasecka, A.

Publications and source records attributed to Piasecka, A..

7 recordsLinked to original sources

bioRxiv2026

Loss of a conserved disulfide bond defines Penetration2-related immune myrosinases in Brassicaceae

O_LIThis study investigated whether PEN2/BGLU26 has uniquely evolved as an indole glucosinolate-hydrolysing myrosinase required for Arabidopsis thaliana pre-invasive immunity, or whether related myrosinases can replace its function when targeted to the same subcellular context. C_LIO_LIPEN2-homologous and other selected myrosinases from A. thaliana and Brassica rapa were expressed in the pen2-2 mutant background using a PEN2-like targeting strategy. The resulting lines were assessed by gene expression, protein accumulation, metabolite analysis and pathogen resistance assays. In parallel, targeted mutagenesis, structural comparison and phylogenetic analysis were used to examine molecular and evolutionary features of PEN2-related myrosinases. C_LIO_LIAtBGLU27 and BrBABG.a, but not AtBGLU18, AtBGLU23 or AtBGLU28, partially restored indole glucosinolate hydrolysis and resistance to Colletotrichum tropicale in pen2-2. Unlike AtPEN2, both enzymes acted mainly constitutively and showed distinct substrate preferences. PEN2, BGLU27 and BABG proteins lacked conserved post-translational modification sites, including residues associated with a conserved disulfide bond. Restoring this disulfide bond in AtPEN2 abolished its activity. C_LIO_LIPEN2-related myrosinases form an evolutionarily distinct BGLU lineage associated with indole glucosinolate metabolism in Brassicales. Loss of the conserved disulfide bond appears to be required for PEN2 activity, whereas additional PEN2-specific regulatory features are needed for pathogen-triggered, rather than constitutive, glucosinolate metabolism. C_LI

plant biology↗

bioRxiv2022

Tryptophan specialized metabolism and ER body-resident myrosinases modulate root microbiota assembly

Indole glucosinolates (IGs) are tryptophan (Trp)-derived sulfur-containing specialized metabolites that play a crucial role in plant-microbe interactions in plants of the order Brassicales, including Arabidopsis thaliana. Despite the growing body of evidence implicating IG biosynthetic pathways in root-microbiota interactions, how myrosinases, the enzymes that convert inert IGs into bioactive intermediate/terminal products, contribute to this process remains unknown. Here, we describe the roles of the PYK10 and BGLU21 myrosinases in root-microbiota assembly partly via metabolites secreted from roots into the rhizosphere. PYK10 and BGLU21 localize to the endoplasmic reticulum (ER) body, an ER-derived organelle observed in plants of the family Brassicaceae. We investigated the root microbiota structure of mutants defective in the Trp metabolic (cyp79b2b3 and myb34/51/122) and ER body (nai1 and pyk10bglu21) pathways and found that these factors together contribute to the assembly of root microbiota. Microbial community composition in soils as well as in bacterial synthetic communities (SynComs) treated with root exudates axenically collected from pyk10bglu21 and cyp79b2b3 differed significantly from those treated with exudates derived from wild-type plants, pointing to a direct role of root-exuded compounds. We also show that growth of the pyk10bglu21 and cyp79b2b3 mutants was severely inhibited by fungal endophytes isolated from healthy A. thaliana plants. Overall, our findings demonstrate that root ER body-resident myrosinases influencing the secretion of Trp-derived specialized metabolites represent a lineage-specific innovation that evolved in Brassicaceae to regulate root microbiota structure. SignificanceER bodies were first identified in roots of Brassicaceae plants more than 50 years ago, but their physiological functions have remained uncharacterized. A series of previous studies have suggested their possible role in root-microbe interactions. Here, we provide clear experimental evidence showing a role for ER bodies in root-microbiota interactions, which overlaps with that of root-exuded Trp-derived metabolites. Our findings delineate a plant lineage-specific innovation involving intracellular compartments and metabolic enzymes that evolved to regulate plant-microbe interactions at the root-soil interface.

plant biology↗

bioRxiv2022

Loss of MYB34 transcription factor that controls feedback loop in indole glucosinolate biosynthesis supports backward evolution of this pathway within Camelineae tribe

Glucosinolates are specialized defensive metabolites characteristic for the Brassicales order. Among them aliphatic and indolic glucosinolates (IGs) are usually highly abundant in the species from Brassicaceae family. The exception from this trend is constituted by species representing a subclade of Camelineae tribe, including Capsella and Camelina genera, which have reduced capacity to produce and metabolize IGs. Our study addresses contribution of specific glucosinolate-related MYB transcription factors to this unprecedented backward evolution of IG biosynthesis. To this end we performed phylogenomic and functional studies of respective MYB proteins. Obtained results revealed weakened conservation of glucosinolate-related MYB transcription factors, including loss of functional MYB34 protein, in the investigated species. We showed that introduction of functional MYB34 from Arabidopsis thaliana partially restores IG biosynthesis in Capsella rubella indicating that loss of this transcription factor contributes to the backward evolution of this metabolic pathway. Finally, we performed analysis of the impact of particular myb mutations on the feedback loop in IG biosynthesis, which drives auxin overproduction, metabolic dysregulation and strong growth retardation caused by mutations in IG biosynthetic genes. This uncovered unique function of MYB34 among IG-related MYBs in this feedback regulation and consequently in IG conservation in Brassicaceae plants.

plant biology↗

bioRxiv2020

Gene expression evolution in pattern-triggered immunity within Arabidopsis thaliana and across Brassicaceae species

Plants recognize surrounding microbes by sensing microbe-associated molecular patterns (MAMPs) to activate pattern-triggered immunity (PTI). Despite their significance for microbial control, the evolution of PTI responses remains largely uncharacterized. Employing comparative transcriptomics of six Arabidopsis thaliana accessions and three additional Brassicaceae species for PTI responses to the MAMP flg22, we identified a set of genes with expression changes under purifying selection in the Brassicaceae species and genes exhibiting species-specific expression signatures. Variation in flg22-triggered transcriptome and metabolome responses across Brassicaceae species was incongruent with their phylogeny while expression changes were strongly conserved within A. thaliana, suggesting directional selection for some species-specific gene expression. We found the enrichment of WRKY transcription factor binding sites in 5-regulatory regions in conserved and species-specific responsive genes, linking the emergence of WRKY-binding sites with the evolution of gene responses in PTI. Our findings advance our understanding of transcriptome evolution during biotic stress.

plant biology↗

bioRxiv2018

Global increase in circRNA levels in myotonic dystrophy

Splicing aberrations induced as a consequence of the sequestration of MBNL splicing factors on the DMPK transcript, which contains expanded CUG repeats, present a major pathomechanism of myotonic dystrophy type 1 (DM1). As MBNLs may also be important factors involved in the biogenesis of circular RNAs (circRNAs), we hypothesized that the level of circRNAs would be decreased in DM1. To test this hypothesis, we selected twenty well-validated circRNAs and analyzed their levels in several experimental systems (e.g., cell lines, DM muscle tissues, and a mouse model of DM1) using droplet digital PCR assays. We also explored the global level of circRNAs using two RNA-Seq datasets of DM1 muscle samples. Contrary to our original hypothesis, our results consistently showed a global increase in circRNA levels in DM1 and we identified numerous circRNAs that were increased in DM1. We also identified many genes (including muscle-specific genes) giving rise to numerous (>10) circRNAs. Thus, this study is the first to show an increase in global circRNA levels in DM1. We also provided preliminary results showing the association of circRNA level with muscle weakness and alternative splicing changes that are biomarkers of DM1 severity. Author SummaryRecently, a great deal of interest has been focused on a new class of RNA molecules called circular RNAs (circRNAs). To date, thousands of circRNAs have been found in different human cells/tissues. Although the function of circRNAs remains mostly unknown, circRNAs have emerged as an important component of the RNA-RNA and RNA-protein interactome. Thus, intensive efforts are being made to fully understand the biology and function of circRNAs, especially their role in human diseases. As an important role in the biogenesis of circRNA may be played by MBNL splicing factors, in this study we used DM1 (to a lesser extent, DM2) as a natural model in which the level of MBNLs is decreased. In contrast to the expected effect, our results consistently showed a global increase in circRNA levels in DM1. As a consequence, whole genome transcriptome analysis revealed dozens of circRNAs with significantly altered (mostly increased) levels in DM1. Furthermore, we observed that the circRNA levels were in many cases strongly associated with DM1 severity.

molecular biology↗

bioRxiv2017

Identifying a TFIID interactome via integrated biochemical and high-throughput proteomic studies

The core promoter recognition TFIID complex acts as a central regulator for eukaryotic gene expression. To direct transcription initiation, TFIID binds the core promoter DNA and aids recruitment of the transcription machinery (e.g., RNA polymerase II) to the transcription start site. Many transcription factors target TFIID to control vital cellular processes. Current studies on finding TFIID interactors have predominantly focused on transcription factors. Yet, a comprehensive interactome of mammalian TFIID has not been established. Therefore, this study sought to reveal potential TFIID-nucleated networks by identifying likely co-regulatory factors that bind TFIID. By using intact native human TFIID complexes, we have exploited three independent approaches including a high-throughput Next Generation DNA sequencing coupled with proteomic analysis. Among these methods, we found some overlapping and new candidates in which we further assessed three putative interactors (i.e., Sox2, H2A and EMSY) by co-immunoprecipitation assays. Notably, in addition to known TFIID interactors, we identified a number of novel factors that participate either in co-regulatory pathways or non-transcription related functions of TFIID. Overal, these results indicate that, in addition to transcription initiation, mammalian TFIID may be involved in broader regulatory pathways than previous studies suggested.

biochemistry↗

bioRxiv2016

p53 dynamically directs TFIID assembly on target gene promoters

The p53 tumor suppressor protein is a central regulator that turns on vast gene networks to maintain cellular integrity upon various stimuli. p53 activates transcription initiation in part by aiding recruitment of TFIID to the promoter. However, the precise means by which p53 dynamically interacts with TFIID to facilitate assembly on target gene promoters remains elusive. To address this key question, we have undertaken an integrated approach involving single molecule fluorescence microscopy, single particle cryo-electron microscopy, and biochemistry. Our real-time single molecule imaging demonstrates that TFIID alone binds poorly to native p53 target promoters. p53 unlocks TFIIDs ability to bind DNA by increasing TFIID contacts with both the core promoter and a region surrounding p53s response element (RE). Analysis of single molecule dissociation kinetics reveals that TFIID interacts with promoters via transient and prolonged DNA binding modes that are each regulated by p53. Importantly, our structural work reveals that TFIIDs conversion from a canonical form to a rearranged DNA-binding conformation is enhanced in the presence of DNA and p53. Notably, TFIIDs interaction with DNA induces p53 to rapidly dissociate, effectively liberating the RE on the promoter. Collectively, these findings indicate that p53 dynamically escorts and loads the basal transcription machinery onto its target promoters.

biochemistry↗