The establishment of ad/abaxial polarity is a fundamental event in plant development. It is critical for correct polar development of the leaf (the upper portion of the leaf is chloroplast rich and optimized for light capture while the lower portion is optimized for gas exchange) and for creating an environment that allows the formation of new meristems (centers of stem cell growth). Class III homeodomain-leucine zipper (HD-ZIPIII) proteins are conserved plant proteins that act as potent regulators of ad/abaxial polarity. HD-ZIPIII protein activity promotes the development of upper (adaxial) leaf fates and meristem formation; in its absence lower (abaxial) leaf fates develop and meristems fail to form. A network of regulatory factors controls the establishment of ad/abaxial leaf fates. However, this network is incomplete and how these factors control one another is poorly understood. Here we report a new family of plant genes, the LITTLE ZIPPER (ZPR) genes (consisting principally of a stretch of leucine zipper similar to the leucine zipper in HD-ZIPIII proteins) that are transcriptionally up-regulated by HD-ZIPIII activity. Furthermore, we show that the ZPR proteins interact with and repress HD-ZIPIII activity, thus forming a negative feedback loop. Our results suggest that HD-ZIPIII proteins exist in active homodimers and, together with the ZPR proteins, in inactive heterodimers. The newly discovered HD-ZIPIII/ZPR regulatory module would not only serve to dampen the effect of fluctuations in HD-ZIPIII protein levels but more importantly would provide a point of regulation - control over the ratio of inactive heterodimers to active homodimers - that could be influenced by other components of the pathway. For instance, the binding of a small hydrophobic molecule to the conserved (yet little understood) START domain present in the HD-ZIPIII proteins may influence the type of dimer formed.
A feedback regulatory module formed by LITTLE ZIPPER and HD-ZIPIII genes.
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View SamplesVolatiles of certain rhizobacteria can cause growth inhibitory effects on plants/ Arabidopsis thaliana. How these effects are initiated and which mechanisms are enrolled is not yet understood. Obviously the plant can survive/live with the bacteria in the soil, which suggest the existance of a regulatory mechanism/network that provide the possibility for coexistance with the bacteria. To shed light on this regulatory mechanism/network we performed a microarray anlaysis of Arabidopsis thaliana co-cultivated with two different rhizobacteria strains.
Volatiles of two growth-inhibiting rhizobacteria commonly engage AtWRKY18 function.
Age, Specimen part, Time
View SamplesThe mycotoxin deoxynivalenol (DON) is a secondary metabolite from Fusarium species and is frequently present on wheat and other cereals. The main effects of DON are a reduction of the feed intake and reduced weight gain of broilers. At the molecular level DON binds to the 60S ribosomal subunit and inhibits subsequently protein synthesis at the translational level. It has been suggested that cells and tissues with high protein turnover rate, like the liver and small intestine, are most affected by DON. However, little is known about other effects of DON e.g. at the transcriptional level. Therefore we decided to perform a microarray analysis, which allows us the investigation of thousands of transcripts in one experiment.
Fusarium mycotoxin-contaminated wheat containing deoxynivalenol alters the gene expression in the liver and the jejunum of broilers.
Age, Specimen part, Treatment
View SamplesWe measured gene expression of D. melanogaster female heads and abdomens after mating with males from six populations evolved under either enforced monogamy (no male-male competition, 3 populations) or sustained polygamy (intense male-male competition, 3 populations). Overall design: Three samples of virgin female heads and six samples of mated female heads (one each per male evolved population, of which there are three monogamous and three polygamous), for nine libraries. Also, three samples of virgin female abdomens and six samples of mated female abdomens (one each per male evolved population, of which there are three monogamous and three polygamous), for nine libraries. In total, eighteen libraries sequenced in 8 lanes.
Sexual conflict drives male manipulation of female postmating responses in <i>Drosophila melanogaster</i>.
Sex, Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Methylation specifies distinct estrogen-induced binding site repertoires of CBP to chromatin.
Cell line, Treatment, Time
View SamplesCD70TG mice are a model for sterile chronic immune activation and develop Anemia of Inflammation, which is dependent on the production of Ifng by effector CD4 and CD8 T cells.
Chronic IFN-γ production in mice induces anemia by reducing erythrocyte life span and inhibiting erythropoiesis through an IRF-1/PU.1 axis.
Specimen part
View SamplesMultiple signaling pathways ultimately modulate the epigenetic information embedded in the chromatin of gene promoters by recruiting epigenetic enzymes. We found that, in estrogen-regulated gene programming, the acetyltransferase CREB-binding protein (CBP) is specifically and exclusively methylated by the coactivator-associated arginine methyltransferase (CARM1) in vivo. CARM1-dependent CBP methylation and p160 coactivators were required for estrogen-induced recruitment to chromatin targets. Notably, methylation increased the histone acetyltransferase (HAT) activity of CBP and stimulated its autoacetylation. Comparative genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) studies revealed a variety of patterns by which p160, CBP, and methyl-CBP (meCBP) are recruited (or not) by estrogen to chromatin targets. Moreover, significant target gene-specific variation in the recruitment of (1) the p160 RAC3 protein, (2) the fraction of a given meCBP species within the total CBP, and (3) the relative recruitment of different meCBP species suggests the existence of a target gene-specific fingerprint for coregulator recruitment. Crossing ChIP-seq and transcriptomics profiles revealed the existence of meCBP hubs within the network of estrogen-regulated genes. Together, our data provide evidence for an unprecedented mechanism by which CARM1-dependent CBP methylation results in gene-selective association of estrogen-recruited meCBP species with different HAT activities and specifies distinct target gene hubs, thus diversifying estrogen receptor programming.
Methylation specifies distinct estrogen-induced binding site repertoires of CBP to chromatin.
Cell line, Treatment, Time
View SamplesBrain development requires a massive increase in brain lipogenesis and accretion of the essential omega-3 fatty acid docosahexaenoic acid (DHA). Brain acquisition of DHA is primarily mediated by the transporter Major Facilitator Superfamily Domain containing 2a (Mfsd2a) expressed in the endothelium of the blood-brain barrier. Mfsd2a transports DHA and other polyunsaturated fatty acids esterified to lysophosphatidylcholine (LPC-DHA). However, the function of Mfsd2a and DHA in brain development is incompletely understood. Using vascular endothelial-specific (2aECKO) and inducible vascular endothelial-specific (2aiECKO) deletion of Mfsd2a in mice, we found Mfsd2a to be uniquely required postnatally at the blood-brain barrier for normal brain growth and DHA accretion, with DHA deficiency preceding the onset of microcephaly. Gene expression profiling analysis of these DHA deficient brains indicated that Srebp-1 and Srebp-2 pathways were highly elevated.
The lysolipid transporter Mfsd2a regulates lipogenesis in the developing brain.
Specimen part
View SamplesEye photoreceptor membrane discs in outer rod segments are highly enriched in the visual pigment rhodopsin and the omega-3 fatty acid docosahexaenote (DHA). The eye acquires DHA from blood, but transporters for DHA uptake across the blood-retinal barrier (BRB) or retinal pigment epithelium have not been identified. Mfsd2a is a newly described sodium-dependent lysophosphatidylcholine symporter expressed at the BRB.
Mfsd2a Is a Transporter for the Essential ω-3 Fatty Acid Docosahexaenoic Acid (DHA) in Eye and Is Important for Photoreceptor Cell Development.
Specimen part
View Samplesdetermination of gene regulation by sterol and sphingolipid composition
Functional interactions between sphingolipids and sterols in biological membranes regulating cell physiology.
Sex
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