Cyanide is stoichiometrically produced as a co-product of the ethylene biosynthesis pathway, and it is detoxified by the b-cyanoalanine synthase enzyme. The molecular and phenotypical analysis of T-DNA insertional mutants of the mitochondrial b-cyanoalanine synthase CYS-C1 suggests that discrete accumulation of cyanide is not toxic for the plant and does not alter mitochondrial respiration rates, but does act as a strong inhibitor of root hair development. The cys-c1 null allele is defective in root hair formation and accumulates cyanide in root tissues. The root hair defect is phenocopied in wild type plants by the exogenous addition of cyanide to the growth medium and is reversed by the addition of hydroxocobalamin. Hydroxocobalamin not only recovers the root phenotype of the mutant, but also the formation of ROS at the initial step of the root hair tip. Transcriptional profile analysis of the cys-c1 mutant reveals that cyanide accumulation acts as a repressor signal for several genes encoding enzymes involved in cell wall rebuilding and the formation of the root hair tip, as well as genes involved in ethylene signaling and metabolism. Our results demonstrate that mitochondrial b-cyanoalanine synthase activity is essential to maintain a low level of cyanide for proper root hair development.
Mitochondrial beta-cyanoalanine synthase is essential for root hair formation in Arabidopsis thaliana.
Specimen part
View SamplesWe performed a transcriptomic analysis of Pi starvation responses in Arabidopsis thaliana (Columbia-0) wild type plants under phosphate starvation stress and in plants with altered PHR1(-like) activity, comparing mutants of phr1 and phr1-phl1 grown in phosphate-lacking medium. Results show the central role of PHR1 and functionally redundant members of its family in the control of transcriptional responses to Pi starvation.
A central regulatory system largely controls transcriptional activation and repression responses to phosphate starvation in Arabidopsis.
Specimen part
View SamplesWe performed a transcriptomic analysis of Pi starvation responses in Arabidopsis thaliana (Columbia-0) phr1 mutant plants expressing PHR1 in presence of cicloheximide, that inhibit protein translation, thus preventing any effect of PHR1 on the expression of indirect targets. Results show the primary target genes of PHR1 in the responses to Pi starvation.
A central regulatory system largely controls transcriptional activation and repression responses to phosphate starvation in Arabidopsis.
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View SamplesNormal development requires tight regulation of cell proliferation and cell death. Here, we investigated these control mechanisms in the hyaloid vessels, a temporary vascular network in the mammalian eye that requires a Wnt/ß-catenin response for scheduled regression. Transcriptome analysis of the postnatal day 5 mouse hyaloid showed expression of several Wnt pathway proteins. We investigated whether the hyaloid Wnt response was linked to the oncogene Myc, and the cyclin-dependent kinase inhibitor P21 (CDKN1A), both established regulators of cell cycle progression and cell death. Our analysis showed that the Wnt pathway coreceptors LRP5 and LRP6 have overlapping activities mediating the Wnt/ß-catenin signaling in hyaloid vascular endothelial cells (VECs). We also showed that both Myc and Cdkn1a are downstream of the Wnt response and are required for hyaloid regression but for different reasons. Conditional deletion of Myc in VECs suppressed both proliferation and cell death. By contrast, conditional deletion of Cdkn1a resulted in VEC over-proliferation that countered the effects of cell death on regression. When combined with analysis of MYC, and P21 protein levels, this analysis suggests that a Wnt/ß-catenin, MYC-P21 pathway regulates scheduled hyaloid vessel regression. Overall design: Hyaloid vascular preparations from postnatal day 5 mice were harvested in cold PBS and RNA extracted in Tri Reagent. RNA amplifcation was performed on total RNA before cDNA library was made. Samples were then sequenced using Illimina HiSeq2500 to obtain 25-30 million paired-end reads.
Developmental vascular regression is regulated by a Wnt/β-catenin, MYC and CDKN1A pathway that controls cell proliferation and cell death.
Specimen part, Subject
View SamplesBefore birth B-cells develop in the fetal liver (FL). Here we show that Gli3 activity in the FL stroma is required for B-cell development. In the Gli3-deficient FL B-cell development was reduced at multiple stages, whereas the Sonic hedgehog (Shh)-deficient FL showed increased B-cell development, and Gli3 functioned to repress Shh transcription. Use of a transgenic Hedgehog (Hh)-reporter mouse showed that Shh signals directly to developing B-cells, and that Hh pathway activation was increased in developing B-cells from Gli3-deficient fetal liver. RNAsequencing confirmed that Hh-mediated transcription is increased in B-lineage cells from Gli3-deficient FL, and showed that these cells expressed reduced levels of B-lineage transcription factors and BCR/pre-BCR-signalling genes. We showed that expression of the master regulators of B-cell development, Ebf1 and Pax5, is reduced in developing B-cells from Gli3-deficient FL and increased in Shh-deficient FL, and that in vitro Shh-treatment or neutralisation can repress or induce their expression respectively. Overall design: Wildtype and Gli3 mutant (Gli3+/- and Gli3-/-) (n=2) embryonic day 17.5 fetal livers were sorted for CD19+B220+ cells. RNA extracted from these cells was sequenced to help understand the transcriptional changes governing B cell development in the Gli3 mutants.
The transcription factor Gli3 promotes B cell development in fetal liver through repression of Shh.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Phytochrome interacting factors 4 and 5 control seedling growth in changing light conditions by directly controlling auxin signaling.
Age, Specimen part, Treatment
View SamplesAs sessile organisms plants developed a veriety of adaptive responses to the ever changing environment. One of these responses is the shade avoidance syndrome which is composed of different responses like elongation growth, hyponastic leafs or early flowering to shade (low R/FR). Phytochrcome Interacting Factor 4 and 5 are bHLH transcription factors reported to activate gene expression upon perception of low R/FR. Using this miroarray experiment we identified new genes regulated by PIF4 and PIF5 in response to shade and investigated their genome wide role.
Phytochrome interacting factors 4 and 5 control seedling growth in changing light conditions by directly controlling auxin signaling.
Age, Specimen part, Treatment
View SamplesPlants with decreased SWC4 expression levels displayed several pleiotropic phenotypic alterations, suggesting that this gene participates in the regulation of different developmental processes. To evaluate genes whose expression was misregulated in SCW4 RNAi line, we performed RNA-seq differential expression analysis.
Arabidopsis SWC4 Binds DNA and Recruits the SWR1 Complex to Modulate Histone H2A.Z Deposition at Key Regulatory Genes.
Age, Specimen part
View SamplesWe used Affymetrix microarrays to understand the genome wide differences in Wildtype and Gli3 mutant (Gli3+/- and Gli3-/-) (n=2) embryonic day 18.5 DP CD69-, DP CD69+ and SP4 thymocytes.
Gli3 in fetal thymic epithelial cells promotes thymocyte positive selection and differentiation by repression of <i>Shh</i>.
Specimen part
View SamplesIn this study we plan to compare the profiles of control sample (C) with the disease (FSGS) samples to identify differentially expressed genes. We hope to identify genes that are specifically activated in response to treatment with FSGS plasma. Overall design: Upregulated genes on incubating with plasma from recurrent FSGS plamsa sample in cultured human podocytes cells were probed
Development of a novel cell-based assay to diagnose recurrent focal segmental glomerulosclerosis patients.
Specimen part, Disease, Subject
View Samples