Yeast filamentous growth is a stress response to conditions of nitrogen deprivation, wherein yeast colonies form pseudohyphal filaments of elongated and connected cells. As proteins mediating adhesion and transport are required for this growth transition, the protein complement at the yeast cell periphery plays a critical and tightly regulated role in enabling pseudohyphal filamentation. To identify proteins differentially abundant at the yeast cell periphery during pseudohyphal growth, we generated quantitative proteomic profiles of plasma membrane protein preparations under conditions of vegetative growth and filamentation. By iTRAQ chemistry and two-dimensional LC-MS/MS, we profiled 2,463 peptides and 356 proteins, from which we identified eleven differentially abundant proteins that localize to the yeast cell periphery. This protein set includes Ylr414cp, herein renamed Pun1p, a previously uncharacterized protein localized to the plasma membrane compartment of Can1 (MCC). Pun1p abundance is increased two-fold under conditions of nitrogen stress, and deletion of PUN1 abolishes filamentous growth in haploids and diploids; pun1D mutants are non-invasive, lack surface-spread filamentation, grow slowly, and exhibit impaired cell adhesion. Conversely, overexpression of PUN1 results in exaggerated cell elongation under conditions of nitrogen stress. PUN1 contributes to yeast nitrogen signaling, as pun1D mutants misregulate amino acid biosynthetic genes during nitrogen deprivation. By chromatin immunoprecipitation and RT-PCR, we find that the filamentous growth factor Mss11p directly binds to the PUN1 promoter and regulates its transcription. In total, this study provides the first profile of protein abundance during pseudohyphal growth, identifying a previously uncharacterized MCC protein required for wild-type nitrogen signaling and filamentous growth.
A profile of differentially abundant proteins at the yeast cell periphery during pseudohyphal growth.
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View SamplesSigma factors are master regulators of bacterial transcription which direct gene expression of specific subsets of genes. In particular, alternative sigma factors are well-known to be key players of bacterial adaptation to changing environments. To elucidate the regulatory network of sigma factors in P. aeruginosa, an integrative approach including sigma factor-dependent mRNA profiling was performed to define the primary regulon of each sigma factor. Overall design: Sigma factor hyper-expressing strains harboring the sigma factor gene in trans under control of the araBAD promoter and sigma factor deletion mutants were constructed. Under optimal conditions regarding sigma factor activity and optional induction of sigma factor expression, bacteria were harvested and total RNA was extracted. Upon mRNA enrichment, RNA was fragmented and ligated to specific RNA-adapters containing a hexameric barcode sequence for multiplexing. These RNA-libraries were reverse transcribed and amplified resulting in cDNA libraries which were sequenced on Illumina platforms. Sequence reads were separated according to their barcodes and barcode sequences were removed. The short reads were mapped to the genome sequence of the reference strain P. aeruginosa PA14 wild-type using stampy with default settings. The R package DESeq was used for differential gene expression analysis.
Antisense transcription in Pseudomonas aeruginosa.
Disease, Subject
View SamplesWe analyzed the transcriptional profile of P.aeruginosa PA14 grown under 14 different environmental conditions. These included conditions of growth within biofilms, at various temperatures, osmolarities and phosphate concentrations, under anaerobic conditions, attached to a surface and conditions encountered within the eukaryotic host. We found that >30% of the PA14 genome was differentially regulated at least under one of the 14 environmental conditions (referred to as the adaptive transcriptome). Most of the genes were also differentially regulated upon sigma factor hyper expression and/or inactivation (GEO accession number GSE54999) and many of those belonged to primary alternative sigma factor regulons. Overall design: The samples of P. aeruginosa PA14 wild type strain were cultivated under 14 different experimental conditions and were analyzed by RNA-seq. For each condition, at least two biological replicates were generated Please note that PA14 is our standard lab strain used for all generated data in this records. There is no mutation introduced for any of those experiments, and thus, the descriptions only highlight the growth conditions.
Antisense transcription in Pseudomonas aeruginosa.
Cell line, Subject
View SamplesGene regulation via transcription factors influences the metabolic, adaptive and pathogenic capabilities of the organism. We report the transcriptomes of the mutants of six major P. aeruginosa PA14 trancription factors - RhlR, LasR, Anr, GacA, FleQ and CbrB. Overall design: The P. aeruginosa PA14 transposon mutants were analyzed by RNA-seq. All samples were cultivated in LB medium until reaching an OD600 of 2.0. For each biological replicate, three cultures were pooled for RNA extraction, library preparation and sequencing.
Functional modules of sigma factor regulons guarantee adaptability and evolvability.
Subject
View SamplesA complex interplay between ethylene, ETP1/ETP2 F-box proteins, and degradation of EIN2 is essential for triggering ethylene responses in plants.
Interplay between ethylene, ETP1/ETP2 F-box proteins, and degradation of EIN2 triggers ethylene responses in Arabidopsis.
Age, Treatment
View SamplesChronic low dose inorganic arsenic (iAs) exposure leads to changes in gene expression and epithelial-to-mesenchymal transformation. During this transformation, cells adopt a fibroblast-like phenotype accompanied by profound gene expression changes. While many mechanisms have been implicated in this transformation, studies that focus on the role of epigenetic alterations in this process are just emerging. DNA methylation controls gene expression in physiologic and pathologic states. Several studies show alterations in DNA methylation patterns in iAs-mediated pathogenesis, but these studies focused on single genes. We present a comprehensive genome-wide DNA methylation analysis using methyl-sequencing to measure changes between normal and iAs-transformed cells. Additionally, these differential methylation changes correlated positively with changes in gene expression and alternative splicing. Interestingly, most of these differentially methylated genes function in cell adhesion and communication pathways. To gain insight into how genomic DNA methylation patterns are regulated iAs-mediated carcinogenesis, we show that iAs probably targets CTCF binding at the promoter of DNA methyltransferases, regulating their expression. These findings reveal how transcription factor binding regulates DNA methyltransferase to reprogram the methylome in response to an environmental toxin.
Genome-wide DNA methylation reprogramming in response to inorganic arsenic links inhibition of CTCF binding, DNMT expression and cellular transformation.
Specimen part, Cell line, Treatment
View SamplesBoth cigarette smoking and obesity have been implicated in increased risk of clear cell renal cell carcinoma (ccRCC); however, there are limited data regarding the molecular mechanisms that underlie these associations. We used a multi-stage design to identify and validate specific molecular targets that are associated with smoking or obesity-related ccRCC.
ANKS1B is a smoking-related molecular alteration in clear cell renal cell carcinoma.
Specimen part, Subject
View SamplesThe molecular regulation of zygotic genome activation (ZGA) in mammals remains poorly understood. Primed mouse embryonic stem cells contain a rare subset of “2C-like” cells that are epigenetically and transcriptionally similar to the two cell embryo and thus represent an ideal system for studying ZGA transcription regulation. Recently, the transcription factor Dux, expressed exclusively in the minor wave of ZGA, was described to activate many downstream ZGA transcripts. However, it remains unknown what upstream maternal factors initiate ZGA either in a Dux dependent or independent manner. Here we performed a candidate-based overexpression screen, identifying, amongst others, Developmental Pluripotency Associated 2 (Dppa2) and 4 (Dppa4) as positive regulators of 2C-like cells and ZGA transcription. In the germ line, promoter DNA demethylation coincides with upregulation of Dppa2 and Dppa4 which remain expressed until E7.5 when their promoters are remethylated. Furthermore, Dppa2 and Dppa4 are also expressed during iPSC reprogramming at the time 2C-like ZGA transcription transiently peaks. Through a combination of overexpression, knockdown, knockout and rescue experiments, together with transcriptional analyses, we show that Dppa2 and Dppa4 directly regulate the 2C-like cell population and associated transcripts, including Dux and the Zscan4 cluster. Importantly, we tease apart the molecular hierarchy in which the 2C-like transcriptional program is initiated and stabilised. Dppa2 and Dppa4 require Dux to initiate 2C-like ZGA transcription, suggesting they act upstream by directly regulating Dux. Supporting this, ChIP-seq analysis revealed Dppa2 and Dppa4 bind to the Dux promoter and gene body and drive its expression. Zscan4c is also able to induce 2C-like cells in wild type cells, but, in contrast to Dux, can no longer do so in Dppa2/4 double knockout cells, suggesting it may act to stabilise rather than drive the transcriptional network. Our findings suggest a model in which Dppa2/4 binding to the Dux promoter leads to Dux upregulation and activation of the 2C-like transcriptional program which is subsequently reinforced by Zscan4c. Overall design: RNA sequencing of screen hits (3 biological replicates of GFP+ and GFP- sorted cells for each of 12 candidates).
Dppa2 and Dppa4 directly regulate the Dux-driven zygotic transcriptional program.
Specimen part, Cell line, Subject
View SamplesThe liver circadian clock is reprogrammed by nutritional challenge through the rewiring of specific transcriptional pathways. As the gut microbiota is tightly connected to host metabolism, whose coordination is governed by the circadian clock, we explored whether gut microbes influence circadian homeostasis and how they distally control the peripheral clock in the liver. Using fecal transplant procedures we reveal that, in response to high fat diet, the gut microbiota drives PPAR-mediated activation of newly oscillatory transcriptional programs in the liver. Moreover, antibiotics treatment prevents PPAR-driven transcription in the liver, underscoring the essential role of gut microbes in clock reprogramming and hepatic circadian homeostasis. Thus, a specific molecular signature characterizes the influence of the gut microbiome in the liver, leading to the transcriptional rewiring of hepatic metabolism.
Gut microbiota directs PPARγ-driven reprogramming of the liver circadian clock by nutritional challenge.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The synthetic glucocorticoids prednisolone and dexamethasone regulate the same genes in acute lymphoblastic leukemia cells.
Specimen part, Cell line, Treatment
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