Project description:In this study we show that cAMP affects gene expression by altering H3K4me3 marks. Note, "Control" samples are untreated with cAMP.
Project description:Long-term dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids and the outgrowth of microorganisms capable of triggering inflammatory bowel disease. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles. RNA-Seq analysis of the human gut microbiome during consumption of a plant- or animal-based diet.
Project description:Long-term dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids and the outgrowth of microorganisms capable of triggering inflammatory bowel disease. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles.
Project description:Abstract Although a substantial number of hormones and drugs increase cellular cAMP levels, the global impact of cAMP and its major effector mechanism, protein kinase A (PKA), on gene expression is not known. Here we show that treatment of wild-type S49 lymphoma cells for 24 h with 8-(4-chlorophenylthio)-cAMP (CPT-cAMP), a PKA-selective cAMP analog, alters the expression of ~4500 of ~13,600 unique genes. By contrast, gene expression was unaltered in Kin– S49 cells (that lack PKA) incubated with CPT-cAMP. Changes in mRNA and protein expression of several cell-cycle regulators accompanied cAMP-induced G1-phase cell-cycle arrest of wild-type S49 cells. Within 2 h, CPT-cAMP altered expression of 152 genes that contain evolutionarily conserved cAMP-response elements (CRE) within 5 kb of transcriptional start sites, including the circadian clock gene Per1. Thus, cAMP through its activation of PKA produces extensive transcriptional regulation in eukaryotic cells. These transcriptional networks include a primary group of CRE-containing genes and secondary networks that include the circadian clock. Keywords: time-course
Project description:Macropinocytosis is an evolutionarily conserved endocytic pathway that mediates non-selective bulk uptake of extracellular fluid. It is the major route by which axenic Dictyostelium cells obtain nutrients and has emerged as a nutrient-scavenging pathway for mammalian cells. How cells adjust macropinocytic activity in various physiological or developmental contexts is an important question that remains largely unanswered. We discovered that, in Dictyostelium cells, the transcription factors Hbx5 and MybG form a functional complex in the nucleus to maintain macropinocytic activity during the growth stage. In contrast, during starvation-induced multicellular development, the transcription factor complex undergoes nucleocytoplasmic shuttling in response to oscillatory cyclic adenosine 3',5'-monophosphate (cAMP) signals, which leads to increased cytoplasmic retention of the complex and progressive downregulation of macropinocytosis. Therefore, by coupling macropinocytosis-related gene expression to the cAMP oscillation system that facilitates long-range cell-cell communication, the dynamic translocation of the Hbx5-MybG complex orchestrates a population-level adjustment of macropinocytic activity to adapt to changing environmental conditions.
Project description:Besozzi2012 - Oscillatory regimes in the Ras/cAMP/PKA pathway in S.cerevisiae
Mechanistic model of the Ras/cAMP/PKA in yeast S.cerevisiae. The Ras/cAMP/PKA pathway plays a major role in the regulation of metabolism, stress resistance and cell cycle progress and is tightly regulated by multiple feedback loops, exerted by the protein kinase A (PKA). This model investigates the dynamics of the second messenger cAMP on Ras/cAMP/PKA pathway, to determine the effects of the feedback mechanisms on establising stable oscillatory regimes.
The model has been defined according to the stochastic formulation of chemical kinetics [Gillespie DT, 1977]
, which requires to specify the set of molecular species occurring in the pathway and their respective interactions, formally described as a set of biochemical reactions.
The volume considered for this system is 30fL; this value can be used to convert the model into the deterministic formulation.
This model is described in the article:
The role of feedback control mechanisms on the establishment of oscillatory regimes in the Ras/cAMP/PKA pathway in S. cerevisiae.
Besozzi D, Cazzaniga P, Pescini D, Mauri G, Colombo S, Martegani E.
EURASIP J Bioinform Syst Biol. 2012 Jul 20;2012(1):10.
Abstract:
In the yeast Saccharomyces cerevisiae, the Ras/cAMP/PKA pathway is involved in the regulation of cell growth and proliferation in response to nutritional sensing and stress conditions. The pathway is tightly regulated by multiple feedback loops, exerted by the protein kinase A (PKA) on a few pivotal components of the pathway. In this article, we investigate the dynamics of the second messenger cAMP by performing stochastic simulations and parameter sweep analysis of a mechanistic model of the Ras/cAMP/PKA pathway, to determine the effects that the modulation of these feedback mechanisms has on the establishment of stable oscillatory regimes. In particular, we start by studying the role of phosphodiesterases, the enzymes that catalyze the degradation of cAMP, which represent the major negative feedback in this pathway. Then, we show the results on cAMP oscillations when perturbing the amount of protein Cdc25 coupled with the alteration of the intracellular ratio of the guanine nucleotides (GTP/GDP), which are known to regulate the switch of the GTPase Ras protein. This multi-level regulation of the amplitude and frequency of oscillations in the Ras/cAMP/PKA pathway might act as a fine tuning mechanism for the downstream targets of PKA, as also recently evidenced by some experimental investigations on the nucleocytoplasmic shuttling of the transcription factor Msn2 in yeast cells.
This model is hosted on BioModels Database
and identified
by: BIOMD0000000478
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource
for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to the public
domain worldwide. Please refer to CC0 Public Domain
Dedication
for more information.
Project description:Although a substantial number of hormones and drugs increase cellular cAMP levels, the global impact of cAMP and its major effector mechanism, protein kinase A (PKA), on gene expression is not known. Here we show that treatment of wild-type S49 lymphoma cells for 24 h with 8-(4-chlorophenylthio)-cAMP (CPT-cAMP), a PKA-selective cAMP analog, alters the expression of ~4500 of ~13,600 unique genes. By contrast, gene expression was unaltered in Kin- S49 cells (that lack PKA) incubated with CPT-cAMP. Changes in mRNA and protein expression of several cell-cycle regulators accompanied cAMP-induced G1-phase cell-cycle arrest of wild-type S49 cells. Within 2 h, CPT-cAMP altered expression of 152 genes that contain evolutionarily conserved cAMP-response elements (CRE) within 5 kb of transcriptional start sites, including the circadian clock gene Per1. Thus, cAMP through its activation of PKA produces extensive transcriptional regulation in eukaryotic cells. These transcriptional networks include a primary group of CRE-containing genes and secondary networks that include the circadian clock.
Project description:This work uncovers a novel and biologically significant mechanism that directly connects nutrient availability to histone modifications and gene transcription. We report that glycolysis promotes histone H3K4 trimethylation (H3K4me3) by activating Tpk2, a catalytic subunit of protein kinase A (PKA) via the Ras-cyclic AMP (cAMP) pathway. Glucose-activated PKA (Tpk2) inhibits Jhd2-catalyzed H3K4 demethylation by phosphorylating Jhd2 at serine 321 and serine 340. In addition, Tpk2- catalyzed Jhd2 phosphorylation promotes H3K14ac by preventing the binding of Rpd3 at chromatin.
Project description:H3K4 methylation is associated with active genes and, along with H3K27 methylation, is part of a bivalent chromatin mark that typifies poised developmental genes in ESCs. However, its functional roles in ESC maintenance and differentiation are not established. Here we show that mammalian Dpy-30, a core subunit of SET1/MLL complexes, biochemically modulates H3K4 methylation in vitro, and directly regulates chromosomal H3K4me3 throughout the mammalian genome. Depletion of Dpy-30 does not affect ESC self-renewal, but significantly alters the differentiation potential of ESCs, particularly along the neural lineage. The differentiation defect is accompanied by defects in gene induction and H3K4 methylation at key developmental loci. Our results provide strong experimental evidence for the hypothesis that H3K4 methylation is an essential functional component of the bivalent mark during activation of developmental genes in ESCs. Total RNAs from control or knockdown cells before and after RA-mediated differentiation were subjected to Illumina microarray analyses. ChIP-enriched DNA from mouse ES cells was analyzed by Solexa sequencing.