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Blomberg, Jeanette
Publikationer (10 of 16) Visa alla publikationer
Blomberg, J., Tasselius, V., Vergara, A., Karamat, F., Imran, Q. M., Strand, Å., . . . Björklund, S. (2024). Pseudomonas syringae infectivity correlates to altered transcript and metabolite levels of Arabidopsis mediator mutants. Scientific Reports, 14(1), Article ID 6771.
Öppna denna publikation i ny flik eller fönster >>Pseudomonas syringae infectivity correlates to altered transcript and metabolite levels of Arabidopsis mediator mutants
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2024 (Engelska)Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 14, nr 1, artikel-id 6771Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Rapid metabolic responses to pathogens are essential for plant survival and depend on numerous transcription factors. Mediator is the major transcriptional co-regulator for integration and transmission of signals from transcriptional regulators to RNA polymerase II. Using four Arabidopsis Mediator mutants, med16, med18, med25 and cdk8, we studied how differences in regulation of their transcript and metabolite levels correlate to their responses to Pseudomonas syringae infection. We found that med16 and cdk8 were susceptible, while med25 showed increased resistance. Glucosinolate, phytoalexin and carbohydrate levels were reduced already before infection in med16 and cdk8, but increased in med25, which also displayed increased benzenoids levels. Early after infection, wild type plants showed reduced glucosinolate and nucleoside levels, but increases in amino acids, benzenoids, oxylipins and the phytoalexin camalexin. The Mediator mutants showed altered levels of these metabolites and in regulation of genes encoding key enzymes for their metabolism. At later stage, mutants displayed defective levels of specific amino acids, carbohydrates, lipids and jasmonates which correlated to their infection response phenotypes. Our results reveal that MED16, MED25 and CDK8 are required for a proper, coordinated transcriptional response of genes which encode enzymes involved in important metabolic pathways for Arabidopsis responses to Pseudomonas syringae infections.

Ort, förlag, år, upplaga, sidor
Springer Nature, 2024
Nationell ämneskategori
Biokemi och molekylärbiologi
Identifikatorer
urn:nbn:se:umu:diva-222861 (URN)10.1038/s41598-024-57192-x (DOI)38514763 (PubMedID)2-s2.0-85188349282 (Scopus ID)
Forskningsfinansiär
Knut och Alice Wallenbergs Stiftelse, 2015-0056Stiftelsen för strategisk forskning (SSF), SB16-0089Vetenskapsrådet, 2016-03943Vetenskapsrådet, 2016-00796
Tillgänglig från: 2024-04-15 Skapad: 2024-04-15 Senast uppdaterad: 2024-04-15Bibliografiskt granskad
Crawford, T., Karamat, F., Lehotai, N., Rentoft, M., Blomberg, J., Strand, Å. & Björklund, S. (2020). Specific functions for Mediator complex subunits from different modules in the transcriptional response of Arabidopsis thaliana to abiotic stress. Scientific Reports, 10(1), Article ID 5073.
Öppna denna publikation i ny flik eller fönster >>Specific functions for Mediator complex subunits from different modules in the transcriptional response of Arabidopsis thaliana to abiotic stress
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2020 (Engelska)Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 10, nr 1, artikel-id 5073Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Adverse environmental conditions are detrimental to plant growth and development. Acclimation to abiotic stress conditions involves activation of signaling pathways which often results in changes in gene expression via networks of transcription factors (TFs). Mediator is a highly conserved co-regulator complex and an essential component of the transcriptional machinery in eukaryotes. Some Mediator subunits have been implicated in stress-responsive signaling pathways; however, much remains unknown regarding the role of plant Mediator in abiotic stress responses. Here, we use RNA-seq to analyze the transcriptional response of Arabidopsis thaliana to heat, cold and salt stress conditions. We identify a set of common abiotic stress regulons and describe the sequential and combinatorial nature of TFs involved in their transcriptional regulation. Furthermore, we identify stress-specific roles for the Mediator subunits MED9, MED16, MED18 and CDK8, and putative TFs connecting them to different stress signaling pathways. Our data also indicate different modes of action for subunits or modules of Mediator at the same gene loci, including a co-repressor function for MED16 prior to stress. These results illuminate a poorly understood but important player in the transcriptional response of plants to abiotic stress and identify target genes and mechanisms as a prelude to further biochemical characterization.

Ort, förlag, år, upplaga, sidor
Nature Publishing Group, 2020
Nationell ämneskategori
Bioinformatik och systembiologi
Identifikatorer
urn:nbn:se:umu:diva-175085 (URN)10.1038/s41598-020-61758-w (DOI)000563443900012 ()32193425 (PubMedID)2-s2.0-85082040402 (Scopus ID)
Forskningsfinansiär
Knut och Alice Wallenbergs Stiftelse, 2015-0056Vetenskapsrådet, 201603943Vetenskapsrådet, 2016-04319Stiftelsen för strategisk forskning (SSF), SB16-0089
Tillgänglig från: 2020-10-01 Skapad: 2020-10-01 Senast uppdaterad: 2023-03-23Bibliografiskt granskad
Kumar, K. R., Blomberg, J. & Björklund, S. (2018). The MED7 subunit paralogs of Mediator function redundantly in development of etiolated seedlings in Arabidopsis. The Plant Journal, 96(3), 578-594
Öppna denna publikation i ny flik eller fönster >>The MED7 subunit paralogs of Mediator function redundantly in development of etiolated seedlings in Arabidopsis
2018 (Engelska)Ingår i: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 96, nr 3, s. 578-594Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

MED7 is a subunit of the Mediator middle module and is encoded by two paralogs in Arabidopsis. We generated MED7 silenced lines using RNAi to study its impact on Arabidopsis growth and development. Compared with wild type, etiolated seedlings of the MED7 silenced lines exhibited reduced hypocotyl length caused by reduced cell elongation when grown in the dark. The hypocotyl length phenotype was rescued by exogenously supplied brassinosteroid. In addition, MED7 silenced seedlings exhibited defective hook opening in the dark as well as defective cotyledon expansion in the presence of the brassinosteroid inhibitor brassinazole. Whole transcriptome analysis on etiolated seedlings using RNA sequencing revealed several genes known to be regulated by auxin and brassinosteroids, and a broad range of cell wall-related genes that were differentially expressed in the MED7 silenced lines. This was especially evident for genes involved in cell wall extension and remodeling, such as EXPANSINs and XTHs. Conditional complementation with each MED7 paralog individually restored the hypocotyl phenotype as well as the gene expression defects. Additionally, conditional expression of MED7 had no effects that were independent of the Mediator complex on the observed phenotypes. We concluded that the MED7 paralogs function redundantly in regulating genes required for the normal development of etiolated Arabidopsis seedlings.

Ort, förlag, år, upplaga, sidor
John Wiley & Sons, 2018
Nyckelord
Arabidopsis thaliana, MED7, Mediator complex, paralogs, skotomorphogenesis, transcriptional regulation
Nationell ämneskategori
Skogsvetenskap
Identifikatorer
urn:nbn:se:umu:diva-153697 (URN)10.1111/tpj.14052 (DOI)000447881200008 ()30058106 (PubMedID)2-s2.0-85053472634 (Scopus ID)
Forskningsfinansiär
CancerfondenVetenskapsrådetKnut och Alice Wallenbergs StiftelseKempestiftelsernaCarl Tryggers stiftelse för vetenskaplig forskning
Tillgänglig från: 2018-12-05 Skapad: 2018-12-05 Senast uppdaterad: 2024-02-08Bibliografiskt granskad
Holst, M. R., Vidal-Quadras, M., Larsson, E., Song, J., Hubert, M., Blomberg, J., . . . Lundmark, R. (2017). Clathrin-Independent Endocytosis Suppresses Cancer Cell Blebbing and Invasion. Cell Reports, 20(8), 1893-1905
Öppna denna publikation i ny flik eller fönster >>Clathrin-Independent Endocytosis Suppresses Cancer Cell Blebbing and Invasion
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2017 (Engelska)Ingår i: Cell Reports, E-ISSN 2211-1247, Vol. 20, nr 8, s. 1893-1905Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Cellular blebbing, caused by local alterations in cellsurface tension, has been shown to increase the invasiveness of cancer cells. However, the regulatory mechanisms balancing cell-surface dynamics and bleb formation remain elusive. Here, we show that an acute reduction in cell volume activates clathrinindependent endocytosis. Hence, a decrease in surface tension is buffered by the internalization of the plasma membrane (PM) lipid bilayer. Membrane invagination and endocytosis are driven by the tension- mediated recruitment of the membrane sculpting and GTPase-activating protein GRAF1 (GTPase regulator associated with focal adhesion kinase-1) to the PM. Disruption of this regulation by depleting cells of GRAF1 or mutating key phosphatidylinositol- interacting amino acids in the protein results in increased cellular blebbing and promotes the 3D motility of cancer cells. Our data support a role for clathrin-independent endocytic machinery in balancing membrane tension, which clarifies the previously reported role of GRAF1 as a tumor suppressor.

Ort, förlag, år, upplaga, sidor
Cell Press, 2017
Nyckelord
Endocytosis, clathrin-independent endocytosis, membrane blebbing, membrane tension, GRAF1, cancer invasion, cell migration, ARHGAP26, cell surface dynamics, GRAF1-dependent endocytosis
Nationell ämneskategori
Cell- och molekylärbiologi
Identifikatorer
urn:nbn:se:umu:diva-139144 (URN)10.1016/j.celrep.2017.08.006 (DOI)000408154300014 ()28834752 (PubMedID)2-s2.0-85028307075 (Scopus ID)
Tillgänglig från: 2017-09-15 Skapad: 2017-09-15 Senast uppdaterad: 2024-01-17Bibliografiskt granskad
Hoernke, M., Mohan, J., Larsson, E., Blomberg, J., Kahra, D., Westenhoff, S., . . . Lundmark, R. (2017). EHD2 restrains dynamics of caveolae by an ATP-dependent, membrane-bound, open conformation. Proceedings of the National Academy of Sciences of the United States of America, 114(22), E4360-E4369
Öppna denna publikation i ny flik eller fönster >>EHD2 restrains dynamics of caveolae by an ATP-dependent, membrane-bound, open conformation
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2017 (Engelska)Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, nr 22, s. E4360-E4369Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The EH-domain-containing protein 2 (EHD2) is a dynamin-related ATPase that confines caveolae to the cell surface by restricting the scission and subsequent endocytosis of these membrane pits. For this, EHD2 is thought to first bind to the membrane, then to oligomerize, and finally to detach, in a stringently regulated mechanistic cycle. It is still unclear how ATP is used in this process and whether membrane binding is coupled to conformational changes in the protein. Here, we show that the regulatory N-terminal residues and the EH domain keep the EHD2 dimer in an autoinhibited conformation in solution. By significantly advancing the use of infrared reflection-absorption spectroscopy, we demonstrate that EHD2 adopts an open conformation by tilting the helical domains upon membrane binding. We show that ATP binding enables partial insertion of EHD2 into the membrane, where G-domain-mediated oligomerization occurs. ATP hydrolysis is related to detachment of EHD2 from the membrane. Finally, we demonstrate that the regulation of EHD2 oligomerization in a membrane-bound state is crucial to restrict caveolae dynamics in cells.

Nyckelord
EHD2, caveolae, membrane-reshaping protein, membrane-bound protein structure, infrared flection-absorption spectroscopy
Nationell ämneskategori
Biofysik
Identifikatorer
urn:nbn:se:umu:diva-136326 (URN)10.1073/pnas.1614066114 (DOI)000402296700009 ()28223496 (PubMedID)2-s2.0-85020030411 (Scopus ID)
Tillgänglig från: 2017-06-22 Skapad: 2017-06-22 Senast uppdaterad: 2024-02-08Bibliografiskt granskad
Davoine, C., Abreu, I. N., Khajeh, K., Blomberg, J., Kidd, B. N., Kazan, K., . . . Björklund, S. (2017). Functional metabolomics as a tool to analyze Mediator function and structure in plants. PLOS ONE, 12(6), Article ID e0179640.
Öppna denna publikation i ny flik eller fönster >>Functional metabolomics as a tool to analyze Mediator function and structure in plants
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2017 (Engelska)Ingår i: PLOS ONE, E-ISSN 1932-6203, Vol. 12, nr 6, artikel-id e0179640Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Mediator is a multiprotein transcriptional co-regulator complex composed of four modules; Head, Middle, Tail, and Kinase. It conveys signals from promoter-bound transcriptional regulators to RNA polymerase II and thus plays an essential role in eukaryotic gene regulation. We describe subunit localization and activities of Mediator in Arabidopsis through metabolome and transcriptome analyses from a set of Mediator mutants. Functional metabolomic analysis based on the metabolite profiles of Mediator mutants using multivariate statistical analysis and heat-map visualization shows that different subunit mutants display distinct metabolite profiles, which cluster according to the reported localization of the corresponding subunits in yeast. Based on these results, we suggest localization of previously unassigned plant Mediator subunits to specific modules. We also describe novel roles for individual subunits in development, and demonstrate changes in gene expression patterns and specific metabolite levels in med18 and med25, which can explain their phenotypes. We find that med18 displays levels of phytoalexins normally found in wild type plants only after exposure to pathogens. Our results indicate that different Mediator subunits are involved in specific signaling pathways that control developmental processes and tolerance to pathogen infections.

Ort, förlag, år, upplaga, sidor
Public Library Science, 2017
Nationell ämneskategori
Utvecklingsbiologi Genetik
Identifikatorer
urn:nbn:se:umu:diva-140237 (URN)10.1371/journal.pone.0179640 (DOI)000404135800047 ()28640868 (PubMedID)2-s2.0-85021228241 (Scopus ID)
Tillgänglig från: 2017-10-19 Skapad: 2017-10-19 Senast uppdaterad: 2023-03-24Bibliografiskt granskad
Chereji, R. V., Bharatula, V., Elfving, N., Blomberg, J., Larsson, M., Morozov, A. V., . . . Björklund, S. (2017). Mediator binds to boundaries of chromosomal interaction domains and to proteins involved in DNA looping, RNA metabolism, chromatin remodeling, and actin assembly. Nucleic Acids Research, 45(15), 8806-8821
Öppna denna publikation i ny flik eller fönster >>Mediator binds to boundaries of chromosomal interaction domains and to proteins involved in DNA looping, RNA metabolism, chromatin remodeling, and actin assembly
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2017 (Engelska)Ingår i: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 45, nr 15, s. 8806-8821Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Mediator is a multi-unit molecular complex that plays a key role in transferring signals from transcriptional regulators to RNA polymerase II in eukaryotes. We have combined biochemical purification of the Sac-charomyces cerevisiae Mediator from chromatin with chromatin immunoprecipitation in order to reveal Mediator occupancy on DNA genome-wide, and to identify proteins interacting specifically with Mediator on the chromatin template. Tandem mass spectrometry of proteins in immunoprecipitates of mediator complexes revealed specific interactions between Mediator and the RSC, Arp2/Arp3, CPF, CF 1A and Lsm complexes in chromatin. These factors are primarily involved in chromatin remodeling, actin assembly, mRNA 3'-end processing, gene looping and mRNA decay, but they have also been shown to enter the nucleus and participate in Pol II transcription. Moreover, we have found that Mediator, in addition to binding Pol II promoters, occupies chromosomal interacting domain (CID) boundaries and that Mediator in chromatin associates with proteins that have been shown to interact with CID boundaries, such as Sth1, Ssu72 and histone H4. This suggests that Mediator plays a significant role in higher-order genome organization.

Ort, förlag, år, upplaga, sidor
Oxford University Press, 2017
Nationell ämneskategori
Biokemi och molekylärbiologi
Identifikatorer
urn:nbn:se:umu:diva-139789 (URN)10.1093/nar/gkx491 (DOI)000409380900020 ()2-s2.0-85032877707 (Scopus ID)
Tillgänglig från: 2017-10-03 Skapad: 2017-10-03 Senast uppdaterad: 2023-10-24Bibliografiskt granskad
Hoernke, M., Larsson, E., Mohan, J., Blomberg, J., Westenhoff, S., Lundmark, R. & Schwieger, C. (2016). Structural Mechanism in a Membrane Remodelling ATP-ASE. Paper presented at 60th Annual Meeting of the Biophysical-Society, FEB 27-MAR 02, 2016, Los Angeles, CA. Biophysical Journal, 110(3), 578A-578A
Öppna denna publikation i ny flik eller fönster >>Structural Mechanism in a Membrane Remodelling ATP-ASE
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2016 (Engelska)Ingår i: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 110, nr 3, s. 578A-578AArtikel i tidskrift, Meeting abstract (Övrigt vetenskapligt) Published
Nationell ämneskategori
Biofysik
Identifikatorer
urn:nbn:se:umu:diva-121607 (URN)000375143000319 ()
Konferens
60th Annual Meeting of the Biophysical-Society, FEB 27-MAR 02, 2016, Los Angeles, CA
Tillgänglig från: 2016-06-21 Skapad: 2016-06-03 Senast uppdaterad: 2018-06-07Bibliografiskt granskad
Aguilar, X., Blomberg, J., Brännström, K., Olofsson, A., Schleucher, J. & Björklund, S. (2014). Interaction Studies of the Human and Arabidopsis thaliana Med25-ACID Proteins with the Herpes Simplex Virus VP16-and Plant-Specific Dreb2a Transcription Factors. PLOS ONE, 9(5), e98575
Öppna denna publikation i ny flik eller fönster >>Interaction Studies of the Human and Arabidopsis thaliana Med25-ACID Proteins with the Herpes Simplex Virus VP16-and Plant-Specific Dreb2a Transcription Factors
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2014 (Engelska)Ingår i: PLOS ONE, E-ISSN 1932-6203, Vol. 9, nr 5, s. e98575-Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Mediator is an evolutionary conserved multi-protein complex present in all eukaryotes. It functions as a transcriptional coregulator by conveying signals from activators and repressors to the RNA polymerase II transcription machinery. The Arabidopsis thaliana Med25 (aMed25) ACtivation Interaction Domain (ACID) interacts with the Dreb2a activator which is involved in plant stress response pathways, while Human Med25-ACID (hMed25) interacts with the herpes simplex virus VP16 activator. Despite low sequence similarity, hMed25-ACID also interacts with the plant-specific Dreb2a transcriptional activator protein. We have used GST pull-down-, surface plasmon resonance-, isothermal titration calorimetry and NMR chemical shift experiments to characterize interactions between Dreb2a and VP16, with the hMed25 and aMed25-ACIDs. We found that VP16 interacts with aMed25-ACID with similar affinity as with hMed25-ACID and that the binding surface on aMed25-ACID overlaps with the binding site for Dreb2a. We also show that the Dreb2a interaction region in hMed25-ACID overlaps with the earlier reported VP16 binding site. In addition, we show that hMed25-ACID/Dreb2a and aMed25-ACID/Dreb2a display similar binding affinities but different binding energetics. Our results therefore indicate that interaction between transcriptional regulators and their target proteins in Mediator are less dependent on the primary sequences in the interaction domains but that these domains fold into similar structures upon interaction.

Nyckelord
Mediator, Med25, Dreb2a, VP16, conformational changes, NMR, ITC
Nationell ämneskategori
Biokemi och molekylärbiologi
Identifikatorer
urn:nbn:se:umu:diva-91061 (URN)10.1371/journal.pone.0098575 (DOI)000336790800049 ()2-s2.0-84902214268 (Scopus ID)
Anmärkning

Originally included in thesis in manuscript form.

Tillgänglig från: 2014-07-11 Skapad: 2014-07-10 Senast uppdaterad: 2023-03-24Bibliografiskt granskad
Blomberg, J., Aguilar, X., Brännström, K., Rautio, L., Olofsson, A., Wittung-Stafshede, P. & Björklund, S. (2012). Interactions between DNA, transcriptional regulator Dreb2a and the Med25 mediator subunit from Arabidopsis thaliana involve conformational changes. Nucleic Acids Research, 40(13), 5938-5950
Öppna denna publikation i ny flik eller fönster >>Interactions between DNA, transcriptional regulator Dreb2a and the Med25 mediator subunit from Arabidopsis thaliana involve conformational changes
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2012 (Engelska)Ingår i: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 40, nr 13, s. 5938-5950Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Mediator is a multiprotein coregulatory complex that conveys signals from DNA-bound transcriptional regulators to the RNA polymerase II transcription machinery in eukaryotes. The molecular mechanisms for how these signals are transmitted are still elusive. By using purified transcription factor Dreb2a, mediator subunit Med25 from Arabidopsis thaliana, and a combination of biochemical and biophysical methods, we show that binding of Dreb2a to its canonical DNA sequence leads to an increase in secondary structure of the transcription factor. Similarly, interaction between the Dreb2a and Med25 in the absence of DNA results in conformational changes. However, the presence of the canonical Dreb2a DNA-binding site reduces the affinity between Dreb2a and Med25. We conclude that transcription regulation is facilitated by small but distinct changes in energetic and structural parameters of the involved proteins.

Ort, förlag, år, upplaga, sidor
Oxford: Oxford University Press, 2012
Nationell ämneskategori
Biokemi och molekylärbiologi
Identifikatorer
urn:nbn:se:umu:diva-54407 (URN)10.1093/nar/gks265 (DOI)000306970700019 ()22447446 (PubMedID)2-s2.0-84864483191 (Scopus ID)
Tillgänglig från: 2012-04-26 Skapad: 2012-04-25 Senast uppdaterad: 2023-03-24Bibliografiskt granskad
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