Drosophila eye specification an development relies on a collection of transcription factors termed the retinal determination gene network (RDGN). Two members of this network, Eyes absent (EYA) and Sine oculis (SO), form a transcriptional complex in which EYA provides the transactivation function while SO provides the DNA binding activity. EYA also function as a protein tyrosine phosphatase, raising the question of whether transcriptional output is dependent or independent of phosphatase activity. To explore this, we used microarrays together with binding site analysis, quantitative real-time PCR, chromatin immunoprecipitation, genetics, and in vivo expression analysis to identify new EYA-SO targets. In parallel, we examined the expression profiles of tissue expressing phosphatase mutant eya and found that reducing phosphatase activity did not globally impair transcriptional output. Among the targets identified by our analysis was the cell cycle regulatory gene, string (stg), suggesting that EYA and SO may influence cell proliferation through transcriptional regulation of stg. Future investigation into the regulation of stg and other EYA-SO targets identified in this study will help elucidate the transcriptional circuitries whereby output from the RDGN integrates with other signaling inputs to coordinate retinal development.
Identification of transcriptional targets of the dual-function transcription factor/phosphatase eyes absent.
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View SamplesWe have recently demonstrated that mycobacterial ligands engage Toll like receptor 2 (TLR2) on CD4+ T cells and up-regulate T-cell receptor (TCR) triggered- Th1 responses in vitro and in vivo.
Toll like Receptor 2 engagement on CD4<sup>+</sup> T cells promotes TH9 differentiation and function.
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View SamplesGenetically engineered human pluripotent stem cells (hPSCs) have been proposed as a source for transplantation therapies and are rapidly becoming valuable tools for human disease modeling. However, many of the potential applications are still limited by the lack of robust differentiation paradigms that allow for the isolation of defined functional tissues. These challenges could be overcome by the use of adult tissue stem cells derived from hPSCs, as their restricted potential could limit the differentiation towards other undesired linages, and allow in vitro expansion and long- term propagation of fully differentiated tissue. To isolate adult stem cells from hPSCs, we applied genome-editing to generate an LGR5-GFP reporter system and subsequently developed a differentiation protocol for human intestinal tissue comprising an adult stem cell niche and all major cell types of the adult intestine. This novel derivation protocol is highly robust and even permits the isolation of intestinal organoids without the LGR5 reporter. Transcriptional profiling, electron microscopy and functional analysis revealed that such human organoid cultures could be derived with high purity, and a composition and morphology similar to that of cultures obtained from human biopsies. Importantly, hPSC-derived organoids responded to the canonical signaling pathways that control self-renewal and differentiation in the adult human intestinal stem cell compartment. With our ability to genetically engineer hPSCs using site-specific nucleases, this adult stem cell system provides a novel platform by which to study human intestinal disease in vitro. Overall design: RNA from primary organoid samples was isolated from organoid lines that were both cultured for 1-6 months and derived from duodenum, ileum, or rectum biopsies of human subjects as described previously (Sato et al., Gastroenterology 2011) grown in media called WENR+inhibitors. RNA was also isolated from various steps in the culturing and differentiation protocol.
Human intestinal tissue with adult stem cell properties derived from pluripotent stem cells.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Generation of isogenic pluripotent stem cells differing exclusively at two early onset Parkinson point mutations.
Specimen part
View SamplesPatient-specific induced pluripotent stem cells (iPSCs) derived from somatic cells provide a unique tool for the study of human disease in disease relevant cells, as well as a promising source for cell replacement therapies for degenerative diseases. However one of the crucial limitations before realizing the full promise of this disease in a dish approach has been the inability to do controlled experiments under genetically defined conditions. This is particularly relevant for disorders with long latency periods, such as Parkinsons disease (PD), where in vitro phenotypes of patient-derived iPSCs are predicted to be subtle and susceptible to significant epistatic effects of genetic background variations. By combining zinc-finger nuclease (ZFN)-mediated genome editing and iPSC technology we provide a generally applicable solution to this key problem by generating isogenic pairs of disease and control human embryonic stem cells (hESCs) and hiPSCs lines that differ exclusively at a susceptibility variant for PD by modifying a single point mutation (A53T) in the -synuclein gene. The robust capability to genetically correct disease causing point mutations in patient-derived hiPSCs represents not only a significant progress for basic biomedical research but also a major advancement towards hiPSC-based cell replacement therapies using autologous cells.
Generation of isogenic pluripotent stem cells differing exclusively at two early onset Parkinson point mutations.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
LEAFY target genes reveal floral regulatory logic, cis motifs, and a link to biotic stimulus response.
Specimen part
View SamplesThe transition from vegetative growth to flower formation is critical for the survival of flowering plants. The plant-specific transcription factor LEAFY (LFY) has central, evolutionarily conserved roles in this process, both in the formation of the first flower and later in floral patterning. We performed genome-wide binding and expression studies to elucidate the molecular mechanisms by which LFY executes these roles. Our study reveals that LFY directs an intricate regulatory network in control of floral homeotic gene expression and, unexpectedly, controls the expression of genes regulating the response to external stimuli in Arabidopsis. We further show that LFY dampens responses to a bacterial MAMP (microbe-associated molecular pattern) and to pathogen challenge. Our findings suggest a molecular mechanism for the coordination of reproductive stage development and disease response programs in plants. Regulation of these distinct survival programs by a single transcription factor may ensure optimal allocation of plant resources for reproductive fitness.
LEAFY target genes reveal floral regulatory logic, cis motifs, and a link to biotic stimulus response.
Specimen part
View SamplesDeveloping osteoblasts undergo a sequence of three consecutive phases: cell proliferation, extracellular matrix maturation, and mineralization. We investigated pH effects on these phases using the osteoblast-like cell line MC3T3-E1.
MC3T3 osteoblast-like cells cultured at alkaline pH: Microarray data (Affymetrix GeneChip Mouse 2.0 ST).
Sex, Specimen part
View SamplesWe screened for differentially expressed genes in the developing notochord using the Affymetrix microarray system in Xenopus laevis. At late gastrula, we dissected four regions from the embryo, anterior mesoderm, posterior mesoderm, notochord and presomitic mesoderm. Three types of comparison were carried out to generate a list of predominantly notochord expressed genes: (1) Posterior mesoderm vs. anterior mesoderm; notochord genes are expected to be increased since the notochord is located in the posterior mesoderm. (2) Posterior mesoderm vs. whole embryos; notochord genes are expected to be increased. (3) Notochord vs. somite. This comparison sub-divided the group of posterior mesodermal genes identified in (1) and (2). All tissues are dissected using tungsten needles. We first dissected dorsal tissue above the archenteron from late gastrula to early neurula. To loosen tissue, we treated the dissected dorsal explant in a 1% cysteine solution (pH 7.4) and removed the neuroectodermal layer. Anterior mesoderm was dissected corresponding to about the anterior one-third of the archenteron roof, and the rest was collected as posterior mesoderm. The posterior mesodermal explant was dissected into notochord and somites, following a clearly visible border between the two tissues. The accuracy of all dissection was confirmed by RT-PCR of marker genes.
Coordinated activation of the secretory pathway during notochord formation in the Xenopus embryo.
Specimen part
View SamplesStudies on the early embryonic development of Xenopus laevis contributed much to the understanding of vertebrate patterning. Gastrula stages are of particular interest because establishment of the axis and germ layer formation take place during these stages. While many genes belonging to several signaling pathways including FGF, Wnt and TGF-beta, have been implicated in patterning the gastrula embryo, the hierarchical interactions between these factors are incompletely known. To study this question, we took advantage of microarray technology to create a regional gene expression profile for the Xenopus gastrula.
Coordinated activation of the secretory pathway during notochord formation in the Xenopus embryo.
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