We 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 SamplesStress constantly challenges plant adaptation to the environment. Of all stress types, arsenic was a major threat during the early evolution of plants. The most prevalent chemical form of arsenic is arsenate, whose similarity to phosphate renders it easily incorporated into cells via the phosphate transporters. Here we found that arsenate stress provokes a notable transposon burst in plants, in coordination with arsenate/phosphate transporter repression, which immediately restricts arsenate uptake. This repression was accompanied by delocalization of the phosphate transporter from the plasma membrane. When arsenate was removed, the system rapidly restored transcriptional expression and membrane localization of the transporter. We identify WRKY6 as an arsenate-responsive transcription factor that mediates arsenate/phosphate transporter gene expression and restricts arsenate-induced transposon activation. Plants therefore have a dual WRKY-dependent signaling mechanism that modulates arsenate uptake and transposon expression, providing a coordinated strategy for arsenate tolerance and transposon gene silencing.
WRKY6 transcription factor restricts arsenate uptake and transposon activation in Arabidopsis.
Time
View SamplesDeregulated intracellular Ca2+ homeostasis underlies synaptic dysfunction and is a common feature in neurodegenerative processes, including Huntington's disease (HD). DREAM/calsenilin/KChIP-3 is a multifunctional Ca2+ binding protein that controls the expression level and/or the activity of several proteins related to Ca2+ homeostasis, neuronal excitability and neuronal survival. We found that expression of endogenous DREAM (DRE antagonist modulator) is reduced in the striatum of R6 mice, in STHdh-Q111/111 knock in striatal neurons and in HD patients. DREAM down regulation in R6 striatum occurs early after birth, well before the onset of motor coordination impairment, and could be part of an endogenous mechanism of neuroprotection, since i) R6/2 mice hemizygous for the DREAM gene (R6/2xDREAM+/-) showed delayed onset of locomotor impairment and prolonged lifespan, ii) motor impairment after chronic administration of 3-NPA was reduced in DREAM knockout mice and enhanced in daDREAM transgenic mice and, iii) lentiviral-mediated DREAM expression in STHdh-Q111/111 knock in cells sensitizes them to oxidative stress. Transcriptomic analysis showed that changes in gene expression in R6/2 striatum were notably reduced in R6/2xDREAM+/- striatum. Chronic administration of repaglinide, a molecule able to bind to DREAM in vitro and to accelerate its clearance in vivo, delayed the onset of motor dysfunction, reduced striatal loss and prolonged the lifespan in R6/2 mice. Furthermore, exposure to repaglinide protected STHdh-Q111/111 knock in striatal neurons sensitized to oxidative stress by lentiviral-mediated DREAM overexpression. Thus, genetic and pharmacological evidences disclose a role for DREAM silencing in early neuroprotective mechanisms in HD.
Activating transcription factor 6 derepression mediates neuroprotection in Huntington disease.
Specimen part
View SamplesInnate immune response is the first line of antiviral defense resulting, in most cases, in pathogen clearance with minimal clinical consequences. Viruses have developed diverse strategies to evade innate immune response and to ensure their survival. Using transmissible gastroenteritis virus (TGEV) as a model, we previously reported that accessory gene 7 counteracts host antiviral response by its association with the catalytic subunit of protein phosphatase 1 (PP1c). A transcriptomic analysis was performed to further investigate the effect of gene 7 absence on the host cell.
Alphacoronavirus protein 7 modulates host innate immune response.
Specimen part, Cell line, Time
View SamplesDREAM/KChIP-3 is a calcium-dependent transcriptional repressor highly expressed in immune cells. Transgenic mice expressing a dominant active DREAM mutant show reduced serum immunoglobulin levels. In vitro assays show that reduced immunoglobulin secretion is an intrinsic defect of transgenic B cells that occurs without impairment in plasma cell differentiation but with an accelerated entry in cell division and an increase in class switch recombination. B cells from DREAM knockout mice did not show any phenotype, due to compensation by endogenous KChIP-2. Expression arrays revealed modified expression of Edem1 and Derlin3, two proteins related to the ER-associated degradation pathway and of Klf9, a cell-cycle regulator. Our results disclose a function of DREAM and KChIP-2 in Ig subclass production in B lymphocytes.
No associated publication
Specimen part
View SamplesThe statins are a family of inhibitors of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase enzyme, which converts acetyl-CoA into mevalonic acid. Since HMG-CoA reductase catalyzes the rate-limiting step in the mevalonate pathway of cholesterol biosynthesis, it was thought that the major clinical benefit of statins was to reduce cholesterol levels in the bloodstream; statins are thus in wide clinical use for the prevention and treatment of cardiovascular disease. Nonetheless, mevalonate is also the precursor of isoprenoid compounds, which are substrates for the post-translational modification of many proteins involved in cell signaling. The blockade of isoprenoid synthesis might explain the pleiotropic effects described for statins in extrahepatic tissues, including inhibition of pathogen infection and anti-inflammatory and immunomodulatory activities.
A lovastatin-elicited genetic program inhibits M2 macrophage polarization and enhances T cell infiltration into spontaneous mouse mammary tumors.
Sex, Specimen part, Treatment
View SamplesNitric oxide (NO) is considered a key regulator of plant developmental processes and defense. Characterization of root-related phenotypes and the involvement of NO in the regulation of primary root growth.
No associated publication
Specimen part
View SamplesExpression of DREAM in dorsal root ganglia and spinal cord is related to endogenous control mechanisms of acute and chronic pain. In primary sensory trigeminal neurons high levels of endogenous DREAM protein are preferentially localized in the nucleus, suggesting a major transcriptional role. Here, we show that DREAM participates in the control of trigeminal pain perception through the regulation of prodynorphin and BDNF. Furthermore, genome-wide analysis of trigeminal neurons in daDREAM transgenic mice revealed that cathepsin L (CTSL) and the monoglyceride lipase (MGLL) are new DREAM downstream targets and have a role in the regulation of trigeminal nociception.
Transcriptional repressor DREAM regulates trigeminal noxious perception.
Specimen part
View SamplesHeat stress is one of the most prominent and deleterious environmental threads affecting plant growth and development. Upon high temperatures, plants launch specialized gene expression programs that promote stress protection and survival. These programs involve global and specific changes at the transcriptional and translational levels. However the coordination of these processes and their specific role in the establishment of the heat stress response is not fully elucidated.
Analysis of genome-wide changes in the translatome of Arabidopsis seedlings subjected to heat stress.
Specimen part
View SamplesDouble-stranded RNA-binding proteins are key elements in the intracellular localization of mRNA and its local translation. Staufen is a double-stranded RNA binding protein involved in the localised translation of specific mRNAs during Drosophila early development and neuronal cell fate. The human homologue Staufen1 forms RNA-containing complexes that include proteins involved in translation and motor proteins to allow their movement within the cell, but the mechanism underlying translation repression in these complexes is poorly understood. Here we show that human Staufen1-containing complexes contain essential elements of the gene silencing apparatus, like Ago1-3 proteins, and we describe a set of miRNAs specifically associated to complexes containing human Staufen1. Among these, miR124 stands out as particularly relevant because it appears enriched in human Staufen1 complexes and is over-expressed upon differentiation of human neuroblastoma cells in vitro. In agreement with these findings, we show that expression of human Staufen1 is essential for proper dendritic arborisation during neuroblastoma cell differentiation, yet it is not necessary for maintenance of the differentiated state, and suggest potential human Staufen1 mRNA targets involved in this process.
Human Staufen1 associates to miRNAs involved in neuronal cell differentiation and is required for correct dendritic formation.
Cell line
View Samples