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Shaikhali, Jehad
Publications (5 of 5) Show all publications
Kindgren, P., Norén, L., Barajas Lopez, J. d., Shaikhali, J. & Strand, Å. (2012). Interplay between HEAT SHOCK PROTEIN 90 and HY5 Controls PhANG expression in response to the GUN5 Plastid Signal. Molecular Plant, 5(4), 901-913
Open this publication in new window or tab >>Interplay between HEAT SHOCK PROTEIN 90 and HY5 Controls PhANG expression in response to the GUN5 Plastid Signal
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2012 (English)In: Molecular Plant, ISSN 1674-2052, E-ISSN 1752-9867, Vol. 5, no 4, p. 901-913Article in journal (Refereed) Published
Abstract [en]

The presence of genes encoding organellar proteins in different cellular compartments necessitates a tight coordination of expression by the different genomes of the eukaryotic cell. This coordination of gene expression is achieved by organelle-to-nucleus or retrograde communication. Stress-induced perturbations of the tetrapyrrole pathway trigger large changes in nuclear gene expression in plants. Recently, we identified HSP90 proteins as ligands of the putative plastid signal Mg-ProtoIX. In order to investigate whether the interaction between HSP90 and Mg-ProtoIX is biologically relevant, we produced transgenic lines with reduced levels of cytosolic HSP90 in wild-type and gun5 backgrounds. Our work reveals that HSP90 proteins respond to the tetrapyrrole-mediated plastid signal to control expression of photosynthesis-associated nuclear genes (PhANG) during the response to oxidative stress. We also show that the hy5 mutant is insensitive to tetrapyrrole accumulation and that Mg-ProtoIX, cytosolic HSP90, and HY5 are all part of the same signaling pathway. These findings suggest that a regulatory complex controlling gene expression that includes HSP90 proteins and a transcription factor that is modified by tetrapyrroles in response to changes in the environment is evolutionarily conserved between yeast and plants.

Place, publisher, year, edition, pages
Oxford University Press, 2012
Keywords
abiotic/environmental stress, cell signaling, organelle biogenesis/function
National Category
Botany
Research subject
Physiological Botany
Identifiers
urn:nbn:se:umu:diva-60509 (URN)10.1093/mp/ssr112 (DOI)000306668400014 ()2-s2.0-84866378808 (Scopus ID)
External cooperation:
Available from: 2012-10-17 Created: 2012-10-15 Last updated: 2023-03-23Bibliographically approved
Shaikhali, J., Norén, L., Barajas-Lopez, J. d., Srivastava, V., Koenig, J., Sauer, U. H., . . . Strand, Å. (2012). Redox-mediated Mechanisms Regulate DNA Binding Activity of the G-group of Basic Region Leucine Zipper (bZIP) Transcription Factors in Arabidopsis. Journal of Biological Chemistry, 287(33), 27510-27525
Open this publication in new window or tab >>Redox-mediated Mechanisms Regulate DNA Binding Activity of the G-group of Basic Region Leucine Zipper (bZIP) Transcription Factors in Arabidopsis
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2012 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 287, no 33, p. 27510-27525Article in journal (Refereed) Published
Abstract [en]

Plant genes that contain the G-box in their promoters are responsive to a variety of environmental stimuli. Bioinformatics analysis of transcriptome data revealed that the G-box element is significantly enriched in promoters of high light-responsive genes. From nuclear extracts of high light-treated Arabidopsis plants, we identified the AtbZIP16 transcription factor as a component binding to the G-box-containing promoter fragment of light-harvesting chlorophyll a/b-binding protein2.4 (LHCB2.4). AtbZIP16 belongs to the G-group of Arabidopsis basic region leucine zipper (bZIP) type transcription factors. Although AtbZIP16 and its close homologues AtbZIP68 and AtGBF1 bind the G-box, they do not bind the mutated half-sites of the G-box palindrome. In addition, AtbZIP16 interacts with AtbZIP68 and AtGBF1 in the yeast two-hybrid system. A conserved Cys residue was shown to be necessary for redox regulation and enhancement of DNA binding activity in all three proteins. Furthermore, transgenic Arabidopsis lines overexpressing the wild type version of bZIP16 and T-DNA insertion mutants for bZIP68 and GBF1 demonstrated impaired regulation of LHCB2.4 expression. Finally, overexpression lines for the mutated Cys variant of bZIP16 provided support for the biological significance of Cys330 in redox regulation of gene expression. Thus, our results suggest that environmentally induced changes in the redox state regulate the activity of members of the G-group of bZIP transcription factors.

Place, publisher, year, edition, pages
Rockville: The American Society for Biochemistry and Molecular Biology, 2012
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-61574 (URN)10.1074/jbc.M112.361394 (DOI)000307840700027 ()2-s2.0-84865028379 (Scopus ID)
External cooperation:
Available from: 2012-11-27 Created: 2012-11-20 Last updated: 2023-03-23Bibliographically approved
Shaikhali, J., Barajas-Lopez, J. d., Ötvös, K., Kremnev, D., Garcia, A. S., Srivastava, V., . . . Strand, Å. (2012). The CRYPTOCHROME1-Dependent Response to Excess Light Is Mediated through the Transcriptional Activators ZINC FINGER PROTEIN EXPRESSED IN INFLORESCENCE MERISTEM LIKE1 and ZML2 in Arabidopsis. The Plant Cell, 24(7), 3009-3025
Open this publication in new window or tab >>The CRYPTOCHROME1-Dependent Response to Excess Light Is Mediated through the Transcriptional Activators ZINC FINGER PROTEIN EXPRESSED IN INFLORESCENCE MERISTEM LIKE1 and ZML2 in Arabidopsis
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2012 (English)In: The Plant Cell, ISSN 1040-4651, E-ISSN 1532-298X, Vol. 24, no 7, p. 3009-3025Article in journal (Refereed) Published
Abstract [en]

Exposure of plants to light intensities that exceed the electron utilization capacity of the chloroplast has a dramatic impact on nuclear gene expression. The photoreceptor Cryptochrome 1 (cry1) is essential to the induction of genes encoding photoprotective components in Arabidopsis thaliana. Bioinformatic analysis of the cry1 regulon revealed the putative ciselement CryR1 (GnTCKAG), and here we demonstrate an interaction between CryR1 and the zinc finger GATA-type transcription factors ZINC FINGER PROTEIN EXPRESSED IN INFLORESCENCE MERISTEM LIKE1 (ZML1) and ZML2. The ZML proteins specifically bind to the CryR1 cis-element as demonstrated in vitro and in vivo, and TCTAG was shown to constitute the core sequence required for ZML2 binding. In addition, ZML2 activated transcription of the yellow fluorescent protein reporter gene driven by the CryR1 cis-element in Arabidopsis leaf protoplasts. T-DNA insertion lines for ZML2 and its homolog ZML1 demonstrated misregulation of several cry1-dependent genes in response to excess light. Furthermore, the zml1 and zml2 T-DNA insertion lines displayed a high irradiance-sensitive phenotype with significant photoinactivation of photosystem II (PSII), indicated by reduced maximum quantum efficiency of PSII, and severe photobleaching. Thus, we identified the ZML2 and ZML1 GATA transcription factors as two essential components of the cry1-mediated photoprotective response.

National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-61232 (URN)10.1105/tpc.112.100099 (DOI)000308352800024 ()2-s2.0-84864975458 (Scopus ID)
Available from: 2012-11-07 Created: 2012-11-07 Last updated: 2023-03-24Bibliographically approved
Shaikhali, J. & Baier, M. (2010). Ascorbate regulation of 2-Cys peroxiredoxin-A promoter activity is light-dependent. Journal of plant physiology (Print), 167(6), 461-467
Open this publication in new window or tab >>Ascorbate regulation of 2-Cys peroxiredoxin-A promoter activity is light-dependent
2010 (English)In: Journal of plant physiology (Print), ISSN 0176-1617, E-ISSN 1618-1328, Vol. 167, no 6, p. 461-467Article in journal (Refereed) Published
Abstract [en]

The 2-Cys peroxiredoxin-A (2CPA) promoter is a model promoter to study redox and ABA-dependent stress signaling. Here, an Arabidopsis reporter gene line expressing luciferase under control of the 2CPA promoter was used to study the impact of ascorbate on reporter gene transcription in a series of protoplast and leaf slice incubation experiments. It was shown that ascorbate has a dual function on gene expression regulation. First, a comparison of responses to ascorbate, dehydroascorbate and reduced and oxidized glutathione demonstrated that ascorbate feeding supports gene expression regulation by increasing the catalytic capacity in redox signaling, as defined by the concentration of low molecular weight antioxidants and their oxidized counterparts. Second, ascorbate had a specific and light-dependent effect on 2CPA transcription, which cannot be substituted by reduced glutathione. Based on the differences between ascorbate and glutathione in the subcellular redox-cycling capacities, it is concluded that ascorbate feeding modulates chloroplast-specific regulation of 2CPA expression. (C) 2009 Elsevier GmbH. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2010
Keywords
Ascorbate, 2-Cys peroxiredoxin, Promoter, Signaling, Transcription
National Category
Plant Biotechnology
Identifiers
urn:nbn:se:umu:diva-109040 (URN)10.1016/j.jplph.2009.10.021 (DOI)000276637600007 ()20022402 (PubMedID)2-s2.0-77649183811 (Scopus ID)
Available from: 2015-09-25 Created: 2015-09-17 Last updated: 2023-03-24Bibliographically approved
Kindgren, P., Barajas López, J. d., Shaikhali, J., Benedict, C., Mohapatra, A., Gough, S. P., . . . Strand, Å. (2010). Interaction between Mg-protoporphyrin IX and HEAT SHOCK PROTEIN 81 is essential for regulation of LHCB expression during plant stress response: .
Open this publication in new window or tab >>Interaction between Mg-protoporphyrin IX and HEAT SHOCK PROTEIN 81 is essential for regulation of LHCB expression during plant stress response:
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2010 (English)Manuscript (preprint) (Other academic)
Publisher
p. 213
Identifiers
urn:nbn:se:umu:diva-36162 (URN)
Available from: 2010-09-21 Created: 2010-09-21 Last updated: 2022-01-24
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