Plant meristems carry pools of continuously active stem cells, whose activity is controlled by developmental and environmental signals. After stem cell division, daughter cells that exit the stem cell domain acquire transit amplifying cell identity before they are incorporated into organs and differentiate. In this study, we used an integrated approach to elucidate the role of HECATE (HEC) genes in regulating developmental trajectories of shoot stem cells in Arabidopsis thaliana. Our work reveals that HEC function stabilizes cell fate in distinct zones of the shoot meristem thereby controlling the spatio-temporal dynamics of stem cell differentiation. Importantly, this activity is concomitant with the local modulation of cellular responses to cytokinin and auxin, two key phytohormones regulating cell behaviour. Mechanistically, we show that HEC factors directly modulate auxin signal transduction by physical interaction with MONOPTEROS (MP), a key regulator of auxin signalling, and thus interfere with the autocatalytic stabilization of auxin signalling. Overall design: p16:HEC1-linker-GR;inflorescence meristems; 14hours; mock1,mock2,mock3,dex1,dex2,dex3
Control of plant cell fate transitions by transcriptional and hormonal signals.
Age, Specimen part, Subject
View SamplesLow oxygen stress dynamically regulates the translation of cellular mRNAs as a means of energy conservation in seedlings of Arabidopsis thaliana. Most of the highly hypoxia-induced mRNAs are recruited to polysomes and actively translated, whereas other cellular mRNAs become translationally inactive and are either targeted for stabilization or degradation. Here we identify the involvement of OLIGOURIDYLATE BINDING PROTEIN 1 (UBP1), a triple RNA Recognition Motif protein, in dynamic and reversible aggregation of translationally repressed mRNAs during hypoxia. Mutation or downregulation of UBP1C interferes with seedling establishment and reduces survival of low oxygen stress. By use of messenger ribonucleoprotein immunopurification, we show that UBP1C constitutively binds a subpopulation of mRNAs characterized by U-rich 3-untranslated regions under normoxic conditions. During hypoxia, UBP1C association with non-U-rich mRNAs is enhanced concomitant with its aggregation into microscopically visible cytoplasmic foci, referred to as UBP1 stress granules (SGs). This UBP1C-mRNA association occurs as global levels of protein synthesis decline. Upon reoxygenation, rapid UBP1 SG disaggregation coincides with the return of the stabilized mRNAs to polysomes. The mRNAs that are highly induced and translated during hypoxia largely circumvent UBP1C sequestration. Thus, UBP1 is established as a component of dynamically assembled cytoplasmic mRNPs that sequester mRNAs that are poorly translated during a transient low energy stress.
Selective mRNA sequestration by OLIGOURIDYLATE-BINDING PROTEIN 1 contributes to translational control during hypoxia in Arabidopsis.
Specimen part, Disease, Treatment
View SamplesMicroarray experiment with polysomal and non-polysomal RNAs extracted under non-stress and mild-dehydration stress.
mRNA sequence features that contribute to translational regulation in Arabidopsis.
No sample metadata fields
View SamplesTranscriptome, translatome, and CSP1 RNA regulon analysis of 25-d-o Arabidopsis rosettes exposed to 12h low temperature (4C) treatment.
Cold shock proteinĀ 1 chaperones mRNAs during translation in Arabidopsis thaliana.
Age, Specimen part, Treatment
View Samples7d-old WT ler seedlings were submitted to 12h of non-stress (air) or hypoxia-stress treatment under low light conditions (45 uM m-2 s-2), and Total and Large Polysome RNA from both treatments were extracted and hybridized against Affymetrix genome chips. Values were used to evaluate changes in transcript abundance and transcript association with large polysomal complexes.
Genome-wide analysis of transcript abundance and translation in Arabidopsis seedlings subjected to oxygen deprivation.
No sample metadata fields
View SamplesGene expression analysis of 7d-old Arabidopsis seedlings exposed to short term (2 h) hypoxia, long term (9 h) hypoxia, and 1 h reoxygenation after long term (9 h) hypoxia to evaluate the regulation of gene expression at the level of translation.
Selective mRNA translation coordinates energetic and metabolic adjustments to cellular oxygen deprivation and reoxygenation in Arabidopsis thaliana.
Age
View SamplesMPK6 shows transient increase in activity under hypoxia with maximal activity at 2 hrs. To study the role of MPK6 in hypoxia in Arabidopsis, 10 do seedlings of WT, mpk6 and MPK6 plants were exposed to 2 hrs hypoxia and 2hr air (mock).
Transient MPK6 activation in response to oxygen deprivation and reoxygenation is mediated by mitochondria and aids seedling survival in Arabidopsis.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Profiling translatomes of discrete cell populations resolves altered cellular priorities during hypoxia in Arabidopsis.
Age, Specimen part, Treatment
View SamplesPlant organs are comprised of distinct cell types with unique assemblages of mRNAs. This is a collection of CEL files of mRNA profiles of the total steady-state mRNAs and polysomal mRNAs of distinct cell types of the whole root and shoot of 7-d-old Arabidopsis thaliana seedlings. The cell type specific mRNA populations are those present in ribosome-mRNA complexes. This sub-population of mRNAs was obtained by first establishing a collection of Arabidopsis lines that express a FLAG-epitope tagged ribosomal protein L18 (RPL18) directed by promoters expressed in specific cell types and regions. Thirteen different promoter:FLAG-RPL18 lines were used. The targeted cell types and promoters included root atrichoblast (non-hair) epidermal cells (pGL2), root endodermis (pSCR), root stelar xylem and pericycle (pWOL, pSHR), root phloem companion cells (phloem CC) (pSUC2, pSultr2;2), root proliferating cells (pRPL11C), root cortex meristematic cells (pCO2), root cortex elongation/maturation cells (pPEP), shoot mesophyll (pRBCS), shoot epidermis (pCER5), shoot guard cells (pKAT1), shoot bundle sheath (pSultr2;2), shoot phloem CC (pSUC2) and shoot trichomes (pGL2). A CaMV 35S promoter:FLAG-RPL18 line was used to obtain the polysomal mRNA of multiple cell types. The immunopurification of ribosome-mRNA complexes of specific cell types/regions was accomplished by the method described in Zanetti et al. (Plant Physiology, 138, 624-635; 2005). Hybridization of the immunopurified mRNAs to the Affymetrix ATH1 DNA microarray platform and subsequent data analysis permitted the identification of transcripts that are enriched or depleted in specific cell types/regions of roots and shoots. The dataset includes samples from cell types/regions from seedlings grown under control conditions and cell types/regions of seedlings exposed to low oxygen stress (hypoxia) for 2 h.
Profiling translatomes of discrete cell populations resolves altered cellular priorities during hypoxia in Arabidopsis.
Age, Specimen part, Treatment
View SamplesPlant organs are comprised of distinct cell types with unique assemblages of mRNAs. This is a collection of CEL files of mRNA profiles of the total steady-state mRNAs and polysomal mRNAs of distinct cell types of the root tip of 7-d-old Arabidopsis thaliana seedlings. The cell type specific mRNA populations are those present in ribosome-mRNA complexes. This sub-population of mRNAs was obtained by first establishing a collection of Arabidopsis lines that express a FLAG-epitope tagged ribosomal protein L18 (RPL18) directed by promoters expressed in specific cell types and regions. Four different promoter:FLAG-RPL18 lines were used. The targeted cell types and promoters included root endodermis (pSCR) and root stelar xylem and pericycle (pWOL, pSHR). A CaMV 35S promoter:FLAG-RPL18 line was used to obtain the polysomal mRNA of multiple cell types. The immunopurification of ribosome-mRNA complexes of specific cell types was accomplished by the method described in Zanetti et al. (Plant Physiology, 138, 624-635; 2005). Hybridization of the immunopurified mRNAs to the Affymetrix ATH1 DNA microarray platform and subsequent data analysis permitted the identification of transcripts that are enriched or depleted in specific cell types of root tips. The dataset includes samples from cell types from seedlings grown under control conditions and cell types of seedlings exposed to low oxygen stress (hypoxia) for 2 h.
Profiling translatomes of discrete cell populations resolves altered cellular priorities during hypoxia in Arabidopsis.
Age, Specimen part, Treatment
View Samples