The Growth Regulating Factors (GRFs) are plant specific transcription factors. They form complexes with GRF Interacting Factors (GIFs), a small family of transcriptional co-activators. In Arabidopsis thaliana, seven out of the nine GRFs are regulated by microRNA miR396. A detailed analysis of GRF3 revealed that a modified transgene, insensitive to the regulation of miR396, causes a strong increase in the number of cells in leaves, while an additional increase of GIF1 expression further enhances the number of cells synergistically. Genome-wide transcript profiling revealed that simultaneous increase of GRF3 and GIF1 levels causes additional effects in gene expression compared to either of the transgenes alone. We observed that GIF1 interacts in vivo with GRF3, as well as chromatin remodeling complexes, providing a mechanistic explanation for the additional activities of a GRF3-GIF1 complex. Interestingly, we found that the GRF system also regulates leaf longevity. Genetic and molecular analysis revealed that the functions of GRFs in leaf size and senescence can be uncoupled, demonstrating that the GRFs control different stages of leaf development. The results provide new insights into the functions of a complex regulatory network composed of microRNAs, transcription factors, and co-transcription factors.
Post-transcriptional control of GRF transcription factors by microRNA miR396 and GIF co-activator affects leaf size and longevity.
Specimen part
View SamplesThe transcriptional coactivator ANGUSTIFOLIA 3 (AN3) stimulates cell proliferation during Arabidopsis leaf development, but the molecular mechanism is largely unknown. We show here that inducible nuclear localization of AN3 during initial leaf growth results in differential expression of important transcriptional regulators, including GROWTH REGULATING FACTORs (GRFs). Chromatin purification further revealed the presence of AN3 at the loci of GRF5, GRF6, CYTOKININ RESPONSE FACTOR 2 (CRF2), CONSTANS-LIKE 5 (COL5), HECATE 1 (HEC1), and ARABIDOPSIS RESPONSE REGULATOR 4 (ARR4). Tandem affinity purification of protein complexes using AN3 as bait identified plant SWITCH/SUCROSE NONFERMENTING (SWI/SNF) chromatin remodeling complexes formed around the ATPases BRAHMA (BRM) or SPLAYED (SYD). Moreover, SWI/SNF ASSOCIATED PROTEIN 73B (SWP73B) is recruited by AN3 to the promoter of GRF5, GRF3, COL5, and ARR4, and both SWP73B and BRM occupy the HEC1 promoter. Furthermore, we show that AN3 and BRM genetically interact. The data indicate that AN3 associates with chromatin remodelers to regulate transcription. In addition, modification of SWI3C expression levels increases leaf size, underlining the importance of chromatin dynamics for growth regulation. Our results place the SWI/SNF-AN3 module as a major player at the transition from cell proliferation to cell differentiation in a developing leaf.
ANGUSTIFOLIA3 binds to SWI/SNF chromatin remodeling complexes to regulate transcription during Arabidopsis leaf development.
Specimen part, Time
View SamplesDeeper understanding of antibiotic-induced physiological responses is critical to identifying means for enhancing our current antibiotic arsenal. Bactericidal antibiotics with diverse targets have been hypothesized to kill bacteria, in part, by inducing production of damaging reactive species. This notion has been supported by many groups, but recently challenged. Here we robustly test the hypothesis using biochemical, enzymatic and biophysical assays along with genetic and phenotypic experiments. We first used a novel intracellular hydrogen peroxide (H2O2) sensor, together with a chemically diverse panel of fluorescent dyes sensitive to an array of reactive species, to demonstrate that antibiotics broadly induce redox stress. Subsequent gene expression analyses reveal that complex antibiotic-induced oxidative stress responses are distinct from canonical responses generated by supra-physiological levels of H2O2. We next developed a method to dynamically quantify cellular respiration and found that bactericidal antibiotics elevate oxygen consumption, indicating significant alterations to bacterial redox physiology. We further show that catalase or DNA mismatch repair enzyme overexpression, as well as antioxidant pre-treatment limit antibiotic lethality, indicating that reactive oxygen species causatively contribute to antibiotic killing. Critically, the killing efficacy of antibiotics was diminished under strict anaerobic conditions, but could be enhanced by exposure to molecular oxygen or addition of alternative electron acceptors, suggesting that environmental factors play a role in killing cells physiologically primed for death. This work provides direct evidence that bactericidal antibiotics, downstream of their target-specific interactions, induce complex redox alterations that contribute to cellular damage and death, thus supporting an evolving, expanded model of antibiotic lethality.
Antibiotics induce redox-related physiological alterations as part of their lethality.
Treatment
View SamplesInterleukin-6 (IL-6) is an important growth factor for estrogen receptor-alpha (ER) positive breast cancer, and elevated serum IL-6 is associated with poor prognosis. We firstly demonstrated that pSTAT3 is the primary downstream IL-6 signaling pathway in ER-positive breast cancer, using ten different breast cancer cell lines. Three-dimensional cultures of these cell lines were also used to develop a 17-gene IL-6 specific gene signature that could be used to identify IL-6 driven disease. This signature included a variety of genes involved in immune cell function and migration, cell growth and apoptosis, and the tumor microenvironment. To further validate this IL-6 signature, we obtained 36 human ER-positive breast cancer tumor samples with matched serum for gene expression profiling and determination of an IL-6 pathway activation score (PAS). Patients with high IL-6 PAS were also enriched for elevated serum IL-6 (>=10 pg/ml). We then utilized a murine MCF-7 xenograft model to determine the role of IL-6 in ER-positive breast cancer and potential anti-IL-6 therapy in vivo. When IL-6 was administered in vivo, MCF-7 cells engrafted without the need for estrogen supplementation. Subsequently, we prophylactically treated mice at MCF-7 engraftment with an anti-IL-6 antibody (siltuximab), fulvestrant or combination therapy. Siltuximab alone was able to blunt MCF-7 engraftment. Similarly, when tumors were allowed to grow to 125 mm3 before treatment, siltuximab alone demonstrated tumor regressions in 90% (9/10) of tumors. Given the established role for IL-6 in ER+ breast cancer, this data demonstrates the potential for anti-IL-6 therapeutics.
Interleukin-6 is a potential therapeutic target in interleukin-6 dependent, estrogen receptor-α-positive breast cancer.
Specimen part
View SamplesWe measured transcriptional changes resulting from overexpression or downregulation of the GTPase Obg.
Obg and Membrane Depolarization Are Part of a Microbial Bet-Hedging Strategy that Leads to Antibiotic Tolerance.
No sample metadata fields
View SamplesTranscriptome of S. cerevisiae in shifts between glucose and maltose media with different re-growth conditions Overall design: Cells are pregrown in maltose, then grown for different durations in glucose and then washed back to maltose
A new protocol for single-cell RNA-seq reveals stochastic gene expression during lag phase in budding yeast.
Subject
View SamplesSomatic ribosomal protein defects have recently been described in cancer, yet their impact on cellular transcription and translation remain poorly understood. Here we integrated mRNA sequencing, ribosome footprinting, polysomal RNA seq and quantitative mass spectrometry datasets obtained from an isogenic mouse lymphoid cell model in order to study the T-cell acute lymphoblastic leukemia (T-ALL) associated R98S mutation in ribosomal protein L10 (RPL10 R98S). RPL10 R98S induced changes in protein levels were to a much larger extent caused by transcriptional then translational changes and RPL10 R98S cells showed a gene signature corresponding to deregulation of hematopoietic transcription factors. Phosphoserine phosphatase (PSPH), a key enzyme in serine biosynthesis, displayed elevated transcription and translation and was one of the proteins showing the strongest upregulation in RPL10 R98S cells. Increased Psph protein levels were confirmed in RPL10 R98S engineered JURKAT cells and in hematopoietic cell cultures derived from Rpl10 R98S knock-in mice. Moreover, elevated serine and glycine biosynthesis in RPL10 R98S cells was supported by metabolic flux analyses. Analysis of PSPH expression levels in T-ALL patient samples revealed that PSPH upregulation is a generalized phenomenon in this disease, associated with elevated circulating serine and glycine levels. Addition of serine and glycine enhanced survival of stromal and myeloid cells, suggesting supportive effects on the hematopoietic niche. Finally, reduction of PSPH expression levels in T-ALL cell lines suppressed their in vitro proliferation and their capacity to expand in T-ALL xenograft models. In conclusion, transcriptome, translatome and proteome analysis of the RPL10 R98S mutation identified RPL10 R98S driven induction of cellular serine biosynthesis. Whereas serine metabolism has been implicated in cancer via PHGDH amplification, this is the first report supporting dependence of ALL cells on the serine biosynthesis enzyme PSPH. Overall design: 3 biological replicates for each condition (RPL10 R98S, RPL10 WT)
Translatome analysis reveals altered serine and glycine metabolism in T-cell acute lymphoblastic leukemia cells.
Specimen part, Subject
View SamplesMicroarrays were used to analyze the gene expression in endoscopic-derived intestinal mucosal biopsies from patients with inflammatory bowel diseas (IBD) and controls
Genetic and Transcriptomic Bases of Intestinal Epithelial Barrier Dysfunction in Inflammatory Bowel Disease.
Specimen part, Disease
View SamplesHypoxia is a low oxygen condition that occurs in the developing tumor mass and that is associated with poor prognosis and resistance to chemo- and radio-therapy. The definition of the hypoxia gene signature is fundamental for the understanding of tumor biology, as in the case of neuroblastoma, the most common pediatric solid tumor. The issue of identifying a significant group of variables in microarray gene expression experiments is particularly difficult due to the typical high dimensional nature of the data and great effort has been spent in the development of feature selection techniques.
A biology-driven approach identifies the hypoxia gene signature as a predictor of the outcome of neuroblastoma patients.
Cell line
View SamplesThe Clade A PP2C Highly ABA-Induced1 (HAI1, At5g59220) is strongly up-regulated by low water potential in an ABA-dependent manner. Using knockout mutants of hai1, we found that HAI1 functions as a negative regulator of low water potential-induced proline and osmoregulatory solute accumulation. We also found a relatively weak and limited interaction of HAI1 with the RCAR/PYL family of ABA receptors. This, plus its induced expression, suggest that HAI1 remains active during stress and attenuates specific aspects of drought response.
Unique drought resistance functions of the highly ABA-induced clade A protein phosphatase 2Cs.
Specimen part, Treatment
View Samples