Coordination of cell division and pattern formation is central to tissue and organ development, and is particularly important in plants where walls prevent cell migration. Auxin and cytokinin are both critical for division and patterning, but it is unknown how these hormones converge to control tissue development. Here, we identify a genetic network that reinforces an early embryonic bias in auxin distribution to create a local, non-responding cytokinin source within the root vascular tissue. We provide experimental and theoretical evidence that these cells act as a local tissue organizer by positioning the domain of oriented cell divisions. We further demonstrate that the auxin-cytokinin interaction acts as a spatial incoherent feed forward loop, which is essential to generate distinct hormonal response zones, thus establishing a stable pattern within a growing vascular tissue.
Plant development. Integration of growth and patterning during vascular tissue formation in Arabidopsis.
Specimen part, Treatment
View SamplesEpidermal keratinocytes respond to extracellular influences by activating cytoplasmic signal transduction pathways that change the transcriptional profiles of affected cells. To define responses to two such pathways, p38 and ERK, we used SB203580 and PD98059 as specific inhibitors, and identified the regulated genes after 1, 4, 24 and 48 hrs, using Affymetrix Hu133Av2 microarrays. Additionally, we compared genes specifically regulated by p38 and ERKs with those regulated by JNK and by all three pathways simultaneously. We find that the p38 pathway induces the expression of extracellular matrix and proliferation-associated genes, while suppressing microtubule-associated genes; the ERK pathway induces the expression of nuclear envelope and mRNA splicing proteins, while suppressing steroid synthesis and mitochondrial energy production enzymes. Both pathways promote epidermal differentiation and induce feedback inactivation of MAPK signaling. c-FOS, SRY and N-Myc appear to be the principal targets of the p38 pathway, Elk-1 SAP1 and HLH2 of ERK, while FREAC-4, ARNT and USF are common to both. The results for the first time comprehensively define the genes regulated by the p38 and ERK pathways in epidermal keratinocytes and suggest a list of targets potentially useful in therapeutic interventions.
Transcriptional profiling defines the roles of ERK and p38 kinases in epidermal keratinocytes.
Specimen part, Treatment
View SamplesTranscriptome analyses on seeds developed in different parental conditions
Effects of Parental Temperature and Nitrate on Seed Performance are Reflected by Partly Overlapping Genetic and Metabolic Pathways.
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View SamplesMature seeds of Arabidopsis thaliana are desiccation tolerant, but they lose DT while progressing to germination. Yet, there is a small developmental window during which DT can be rescued by treatment with abscisic acid (ABA).
A gene co-expression network predicts functional genes controlling the re-establishment of desiccation tolerance in germinated Arabidopsis thaliana seeds.
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View SamplesTo compare the impact of hematopoietic-specific Brpf1 gene inactivation, LSK (Lin-Sca1+cKit1+) cells were sorted from wild-type and Brpf1-null fetal liver cells for RNA-Seq. Overall design: Four E14.5 embryos were used to pool sufficient LSK cells for total RNA isolation and subsequent sequencing on HiSq2500. Two independent pairs of wild-type and mutant RNA samples (each of which contained LSK cells pooled from four embryos) were used for oligo-dT primed RNA Seq.
BRPF1 is essential for development of fetal hematopoietic stem cells.
Specimen part, Subject
View SamplesMature seeds of Arabidopsis thaliana are desiccation tolerant, but they lose DT while progressing to germination. Yet, there is a small developmental window during which DT can be rescued by treatment with polyethylene glycol (PEG).
A gene co-expression network predicts functional genes controlling the re-establishment of desiccation tolerance in germinated Arabidopsis thaliana seeds.
Specimen part, Treatment
View SamplesPlants initially undergo a period of vegetative development, in which it produces leaves from shoot apical meristem (SAM) and roots from the root apical meristem. Later in development, the SAM undergoes a change in fate and enters reproductive development called as floral transition, producing flowers and seeds. Our understanding of the molecular and genetic mechanisms that underlie reproductive development in plants has increased tremendously in the past decade, essentially through the work on Arabidopsis. In this study, we have analyzed the spatial and temporal gene expression in various tissues/organs and developmental stages of rice using microarray technology to identify the genes differentially expressed during various stages of reproductive development.
F-box proteins in rice. Genome-wide analysis, classification, temporal and spatial gene expression during panicle and seed development, and regulation by light and abiotic stress.
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View SamplesDrought, salinity and sub-optimal temperatures are stresses that cause adverse effects on the growth of plants and the productivity of crops. In this study, we have analyzed the expression profiles of rice genes under control and abiotic stress conditions using microarray technology to identify the genes differentially expressed during various abiotic stresses.
F-box proteins in rice. Genome-wide analysis, classification, temporal and spatial gene expression during panicle and seed development, and regulation by light and abiotic stress.
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View SamplesBackground: Evolutionary engineering is a powerful approach to isolate suppressor mutants and industrially relevant genotypes. Until recently, DNA microarray analysis was the only affordable genome-wide approach to identify the responsible mutations. This situation has changed due to the rapidly decreasing costs of whole genome (re)sequencing. DNA microarray-based mRNA expression analysis and whole genome resequencing were combined in a study on lactate transport in Saccharomyces cerevisiae. Jen1p is the only S. cerevisiae lactate transporter reported in literature. To identify alternative lactate transporters, a jen1 strain was evolved for growth on lactate. Results: Two independent evolution experiments yielded Jen1p-independent growth on lactate (max 0.14 and 0.18 h-1 for single-cell lines IMW004 and IMW005, respectively). Whereas mRNA expression analysis did not provide leads, whole-genome resequencing showed different single nucleotide changes (C755G/Leu219Val and C655G/Ala252Gly) in the acetate transporter gene ADY2. Analysis of mRNA levels and depth of coverage of DNA sequencing combined with karyotyping, gene deletions and diagnostic PCR showed that in IMW004 an isochromosome III (~475 kb), which contains two additional copies of ADY2C755G, was formed via crossover between YCLW15 and YCRC6. Introduction of the ADY2 alleles in a jen1 ady2 strain resulted in growth on lactate (max 0.14 h-1 for Ady2pLeu219Val and 0.12 h-1 for Ady2pAla252Gly). Conclusions: Whole-genome resequencing of yeast strains obtained from independent evolution experiments enabled rapid identification of a key gene that was not identified by mRNA expression analysis of the same strains. Reverse metabolic engineering showed that mutated alleles of ADY2 (C655G and C755G) encode efficient lactate transporters.
Laboratory evolution of new lactate transporter genes in a jen1Δ mutant of Saccharomyces cerevisiae and their identification as ADY2 alleles by whole-genome resequencing and transcriptome analysis.
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View SamplesWe have identified ZNF423 (also known as Ebfaz, OAZ or Zfp423) as a component critically required for retinoic acid (RA)-induced differentiation. ZNF423 associates with the RAR/RXR nuclear receptor complex and is essential for transactivation in response to retinoids. Down-regulation of ZNF423 expression by RNA interference in neuroblastoma cells results in a growth advantage and resistance to RA-induced differentiation, whereas overexpression of ZNF423 leads to growth inhibition and enhanced differentiation. Futhermore, we show that low ZNF423 expression is associated with poor disease outcome of neuroblastoma patients. To identify the other key pathways regulated by ZNF423 in human neuroblastoma, we expressed elevated levels of ZNF423 in SH-SY5Y cells and performed full genome gene expression analysis in these cells.
ZNF423 is critically required for retinoic acid-induced differentiation and is a marker of neuroblastoma outcome.
Specimen part
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