A critical step in regeneration is recreating the cellular identities and patterns of lost organs long after embryogenesis is complete. In plants, perpetual (indeterminate) organ growth occurs in apical stem cell niches, which have been shown to re-establish quickly when damaged or removed (1,2). Here we ask whether the machinery of perpetual organ growth, stem cell activity, is needed for the phase of regeneration that leads to replenishing lost cell identities and patterning, or, whether organ re-establishment enlists a wider group of pluripotent cells. We adapt a root tip regeneration system to Arabidopsis that permits us to assess the molecular and functional recovery of specific cell fates during organ regeneration. These results suggest a rapid restoration of missing cell fate and function in advance of the recovery of stem cell activity. Surprisingly, plants with mutations that fail to maintain stem cell activity were able to re-pattern their distal tip and re-specify lost cell fates. Thus, although stem cell activity is required to resume indeterminate growth (3), our results show it is not necessary for cell re-specification and patterning steps. This implies a regeneration mechanism that coordinates patterning of the whole organ, as in embryogenesis, but is initiated from different starting morphologies. 1. Feldman, L. J. Denovo Origin of Quiescent Center Regenerating Root Apices of Zea-Mays. Planta 128, 207-212 (1976). 2. Xu, J. et al. A molecular framework for plant regeneration. Science 311, 385-8 (2006). 3. Gordon, S. P. et al. Pattern formation during de novo assembly of the Arabidopsis shoot meristem. Development 134, 3539-48 (2007).
Organ regeneration does not require a functional stem cell niche in plants.
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View SamplesWe here show that loss of imprinting (LOI) of IGF2 is a frequent and early event in the development of colon cancer and occurs throughout the large intestine. LOI leads to AKT1-dependent activation and suppression of a defined set of genes, many of which are cell cycle related. Our results further showed that IGF2 induces non-canonical wnt signaling. We hypothesize that IGF2 and Wnt5a cooperate in cancer progression. LOI is an attractive target for tumor prevention or targeted therapy.
Carcinoma of the colon and rectum with deregulation of insulin-like growth factor 2 signaling: clinical and molecular implications.
Specimen part
View SamplesLBH589 is a histone deacetylase (HDAC) inhibitor, treatment and changes in acetylated histones alters gene expression
Pan-histone deacetylase inhibitor panobinostat sensitizes gastric cancer cells to anthracyclines via induction of CITED2.
Cell line, Treatment
View SamplesThe purpose of this experiment is to understand which transcripts are differentially expressed following exposure to TCDD.
TCDD inhibits heart regeneration in adult zebrafish.
Treatment
View SamplesThe discovery of the first histone demethylase in 2004 (LSD1/KDM1) opened new avenues for the understanding of how histone methylation impacts cellular functions. A great number of histone demethylases have been identified since, which are potentially linked to gene regulation as well as to stem cell self-renewal and differentiation. KDM6A/UTY and KDM6B/JMJD3 are both H3K27me3/2-specific histone demethylases, which are known to play a central role in regulation of posterior development, by regulating HOX gene expression. So far nothing is known about the role of histone lysine demethylases (KDMs) during early hematopoiesis. We are studying the role of KDM6A and KDM6B on self-renewal, global gene expression and on local and global chromatin states in embryonic stem cells (ESCs) and during differentiation. In order to completely abrogate KDM6 demethylase activity in ESCs we employed a specific inhibitor (GSK-J4, Kruidenier et al. 2012). Treatment of ESCs with GSK-J4 had no effect on viability and proliferation . However, ESC differentiation in the presence of GSK-J4 was completely abrogated. In conclusion we show that ESC differentiation is completely blockend in the absence of any H3K27 demethylase activity.
Inhibition of KDM6 activity during murine ESC differentiation induces DNA damage.
Cell line, Treatment
View SamplesIn this study gene expression of monocyte-derived macrophages (MDM) from chronic obstructive pulmonary disease (COPD) patients and healthy subjects was investigated. MDM were treated with LPS, a combination of fine TiO2 and ultrafine Printex90 particles, or remained untreated.
Tissue-specific induction of ADAMTS2 in monocytes and macrophages by glucocorticoids.
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View SamplesAP2 transcription factors play important roles in development and cancer, we tried to clarify the role of the so far uncharacterised TFAP2E in colorectal cancer.
TFAP2E-DKK4 and chemoresistance in colorectal cancer.
Cell line
View SamplesHLX was found as a VEGF-A induced gene in HUVEC (B.Schweighofer, submitted). In order to detect genes regulated by HLX HUVEC were infected by recombinant adenovirus expressing HLX for 4, 8, 16 and 32h. RNA was isolated and subjected to microarray analysis using Affymetrix microarray.
The VEGF-regulated transcription factor HLX controls the expression of guidance cues and negatively regulates sprouting of endothelial cells.
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View SamplesStudy of Sox18 regulated genes: Human umbilical vein endothelial cells (HUVEC) were either transduced with adenoviral vectors expressing SOX18 from an IRES-EGFP casette, or IRES-EGFP alone, or left untreated. After 16 hours, mRNA was isolated and analyzed by hybridization to Affymetrix HG-U133A arrays.
The transcription factor SOX18 regulates the expression of matrix metalloproteinase 7 and guidance molecules in human endothelial cells.
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View SamplesIn this study gene expression of human blood classical monocytes (CD14++CD16-), CD16 positive monocytes (consisting of non-classical CD14+16++ and intermediate CD14++CD16+ monocytes) and CD1c+ CD19- dendritic cells from healthy subjects were investigated.
Transcript profiling of CD16-positive monocytes reveals a unique molecular fingerprint.
Specimen part
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