Project description:Candida albicans is associated with humans as both a harmless commensal organism and a pathogen. Cph2 is a transcription factor whose DNA binding domain is similar to mammalian sterol response element binding proteins (SREBPs). SREBPs are master regulators of cellular cholesterol levels, and are highly conserved from fungi to mammals. However, ergosterol biosynthesis is regulated by the zinc finger transcription factor Upc2 in C. albicans and several other yeasts. Cph2 is not necessary for ergosterol biosynthesis, but important for colonization in the murine gastrointestinal tract. Here we demonstrate that Cph2 is a membrane-associated transcription factor that is processed to release the N-terminal DNA binding domain like SREBPs; but its cleavage is not regulated by cellular levels of ergosterol or oxygen. ChIP-Seq shows that Cph2 binds to the promoters of HMS1 and other components of the regulatory circuit for GI tract colonization. In addition, 50% of Cph2 targets are also bound by Hms1 and other factors of the regulatory circuit. Several common targets function at the head of the glycolysis pathway. Thus, Cph2 is an integral part of the regulatory circuit for GI colonization that regulates glycolytic flux. RNA-seq shows a significant overlap in genes differentially regulated by Cph2 and hypoxia, and Cph2 is important for optimal expression of some hypoxia-responsive genes in glycolysis and the citric acid cycle. We suggest that Cph2 and Upc2 regulate hypoxia-responsive expression in different pathways, consistent with a synthetic lethal defect of the cph2 upc2 double mutant in hypoxia. Genome binding/occupancy profiling by high throughput sequencing. ChIP-seq of Cph2 was carried out in a wild-type strain carrying N-terminal myc-tagged Cph2 under the MAL2 promoter (MAL2-myc-Cph2N). IP and INPUT samples from 2 independent experiments, as well as a sample of untagged wild-type control, were sequenced.
Project description:Background: Microorganisms are the major cause of food spoilage during storage, processing and distribution. Pseudomonas fluorescens is a typical spoilage bacterium that contributes to a large extent to the spoilage process of proteinaceous food. RpoS is considered an important global regulator involved in stress survival and virulence in many pathogens. Our previous work revealed that RpoS contributed to the spoilage activities of P. fluorescens by regulating resistance to different stress conditions, extracellular acylated homoserine lactone (AHL) levels, extracellular protease and total volatile basic nitrogen (TVB-N) production. However, RpoS-dependent genes in P. fluorescens remained undefined. Results: RNA-seq transcriptomics analysis combined with quantitative proteomics analysis basing on multiplexed isobaric tandem mass tag (TMT) labeling was performed for the P. fluorescens wild-type strain UK4 and its derivative carrying a rpoS mutation. A total of 375 differentially expressed genes (DEGs) and 212 differentially expressed proteins (DEPs) were identified in these two backgrounds. The DGEs were further verified by qRT-PCR tests, and the genes directly regulated by RpoS were confirmed by 5’-RACE-PCR sequencing. The combining transcriptome and proteome analysis revealed a role of this regulator in several cellular processes, including polysaccharide metabolism, intracellular secretion and extracellular structures, cell well biogenesis, stress responses, ammonia and biogenic amine production, which may contribute to biofilm formation, stress resistance and spoilage activities of P. fluorescens. Moreover, in this work we indeed observed that RpoS contributed to the production of the macrocolony biofilm’s matrix.
Project description:Monoubiquitination of histone H2B on lysine 123 (H2BK123ub) is a transient histone modification considered to be essential for establishing H3K4 and H3K79 trimethylation by Set1/COMPASS and Dot1, respectively. Many of the factors such as Rad6/Bre1, the Paf1 complex, and the Bur1/Bur2 complex were identified to be required for proper histone H3K4 and H3K79 trimethylation, and were shown to function by regulating H2BK123ub levels. Here, we have identified Chd1 as a factor that is required for proper maintenance of H2B monoubiquitination levels, but not for H3K4 and H3K79 trimethylation. Loss of Chd1 results in a substantial loss of H2BK123ub levels with little to no effect on the genome-wide pattern of H3K4 and H3K79 trimethylation. Our data shows that nucleosomal occupancy is reduced in gene bodies in both CHD1 null and K123A backgrounds. We have also demonstrated that Chd1’s function in maintaining H2BK123ub levels is conserved from yeast to human. Our study provides evidence that only small levels of H2BK123ub are necessary for full levels of H3K4 and H3K79 trimethylation in vivo, and points to a role for Chd1 in positively regulating gene expression through promoting nucleosome re-assembly coupled with H2B monoubiquitination. Examination of two histone modifications in wild-type and Chd1 null yeast strains using ChIP-seq. Expression profiling in wild-type and Chd1 null yeast strains using RNA-seq.
Project description:Identification of key genes and pathways regulated by phytohormone ABA during maize seed maturation, using the ABA synthesis-deficient mutant (vp5) and regular maize (Vp5) developing embryos.
Project description:Candida albicans is associated with humans as both a harmless commensal organism and a pathogen. Cph2 is a transcription factor whose DNA binding domain is similar to mammalian sterol response element binding proteins (SREBPs). SREBPs are master regulators of cellular cholesterol levels, and are highly conserved from fungi to mammals. However, ergosterol biosynthesis is regulated by the zinc finger transcription factor Upc2 in C. albicans and several other yeasts. Cph2 is not necessary for ergosterol biosynthesis, but important for colonization in the murine gastrointestinal tract. Here we demonstrate that Cph2 is a membrane-associated transcription factor that is processed to release the N-terminal DNA binding domain like SREBPs; but its cleavage is not regulated by cellular levels of ergosterol or oxygen. ChIP-Seq shows that Cph2 binds to the promoters of HMS1 and other components of the regulatory circuit for GI tract colonization. In addition, 50% of Cph2 targets are also bound by Hms1 and other factors of the regulatory circuit. Several common targets function at the head of the glycolysis pathway. Thus, Cph2 is an integral part of the regulatory circuit for GI colonization that regulates glycolytic flux. RNA-seq shows a significant overlap in genes differentially regulated by Cph2 and hypoxia, and Cph2 is important for optimal expression of some hypoxia-responsive genes in glycolysis and the citric acid cycle. We suggest that Cph2 and Upc2 regulate hypoxia-responsive expression in different pathways, consistent with a synthetic lethal defect of the cph2 upc2 double mutant in hypoxia. Expression profiling by high throughput sequencing. RNA sequencing was performed on wild type and cph2 deletion strains. 2 biological replicates were sequenced for each strain.
Project description:M. smegmatis wild type and glnR deletion strains grown in nitrogen limiting conditions (1 mM ammonium sulphate nitrogen source). Samples taken 1 hour after nitrogen depletion from the media for each strain.
Project description:This project investigates the changes in proteome profiles that occurred in the same set of S. mutans wild-type and lrgAB mutant samples used in our recently published RNA-seq study. To this end, mass spectrometry-based label-free quantitative proteomics, a technology known to enable comprehensive identification and quantification of complete bacterial proteomes, was adapted to study changes in S. mutans intracellular protein levels in response to aeration, heat, and vancomycin stress. Furthermore, the degree of correlation between S. mutans protein abundance profiles and gene expression changes was determined. Further understanding of these combined “-omics” data at the cellular or molecular level will enhance our knowledge of Cid/Lrg-mediated cellular responses of S. mutans to adverse environments. Furthermore, these “-omics” data will serve as a valuable resource that can be mined to help clarify the role of the S. mutans stress response and physiological activity to its dynamic survival in the oral cavity.
Project description:Quantitative variation of epigenetic marks, such as histone modifications, can modify gene expression and eventually contribute to inter-individual phenotypic variation. Our goal is to investigate natural inter-individual variation of the epigenome in a quantitative manner. To probe the degree of natural epigenomic diversity in S. cerevisiae, we compared two unrelated wild strains using replicated Mnase-seq and ChIP-seq profiling at mononucleosomal resolution for H3K14 acetylation.
Project description:Fetal growth restriction (FGR) causes a wide variety of developmental defects in the neonate which can lead to heart disease, diabetes, anxiety and other disorders later in life. The effect of FGR on the immune system, however, is poorly understood. Immune cells throughout development are identified using cell-surface markers to distinguish between subtly different stages. These (surface) proteins, however, do not necessarily generate differences in cellular activity and may thus be only a coincidental shallow guide to classifying cells. High-throughput single-cell transcriptomics using DropSeq was performed on mouse neonate thymuses. The T-cell population was selected through flow cytometry in wild type controls and a placental specific isoform of Igf2 knock-down (igf2-p0). Using this analysis, we discovered skewed T-cell populations in the growth restricted murine neonate indicating a developmental delay. This finding recapitulates the altered immunity found in growth restricted human infants. The T-cell deficit persisted into adulthood, even when body and organ weights approached normal levels due to catch-up growth. This reduction in T-cellularity may have significant implications in adult immunity, adding to the wide variety of fetal origins for adult disease already known.
Project description:CroRS is a cell envelope stress response two-component system in the bacterial pathogen Enterococcus faecalis. Antimicrobial tolerance is the ability of an organism to survive, but not proliferate, upon antimicrobial challenge, and is a known precursor to the development of antimicrobial resistance. We have previously shown that CroRS is essential for antimicrobial tolerance in E. faecalis. Therefore, the aim of this experiment was to determine the teixobactin-induced CroRS regulon to identify key pathways of antimicrobial tolerance. To do this, E. faecalis wild-type and a croRS deletion mutant were grown to mid-exponential phase and challenged with and without teixobactin (0.5 ug/ml) for 1 hour. RNA was subsequently extracted, purified and RNA sequenced. RNA libraries were prepped using the Zymo-Seq RiboFree Total RNA-Seq Library Kit. Sequencing was completed using an Illumina MiSeq (v3) system generating 150 bp paired-end reads.