Project description:We performed DNA-protein interaction (ChIP-seq) analyses for Helicobacter pylori N6 wild-type (WT) and HP1021 deletion mutant (ΔHP1021::aphA-3) under oxidative stress (21% O2) and optimal microaerobic growth (5% O2) conditions. We detected 100 binding sites of HP1021 on the H. pylori N6 chromosome, most of which are promoter-located, likely affecting gene transcription. 84 of 100 identified HP1021 binding sites were located near promoter regions. EMSA and ChIP-qPCR confirmed the binding of HP1021 to the promoter region of a few genes.
Project description:We have profiled various H3 post-translational modifications in a wide range of chromatin-associated mutants in yeast. Those include H3K14ac, H3K4me3, H3K4me2, H3K4me1 and H3K36me3.
Project description:N6-methyladenosine (m6A) is one of the most abundant modifications in eukaryotic RNA. Recent mapping of m6A methylomes in mammals, yeast, and plants as well as characterization of m6A methyltransferases, demethylases, and binding proteins have revealed regulatory functions of this dynamic RNA modification. In bacteria, although m6A is present in ribosomal RNA (rRNA), its occurrence in messenger RNA (mRNA) still remains elusive. Here, we used liquid chromatography-mass spectrometry (LC-MS) to calculate the m6A/A ratio in mRNA from a wide range of bacterial species, which demonstrates that m6A is an abundant mRNA modification in tested bacteria. Subsequent transcriptome-wide m6A profiling in Escherichia coli and Pseudomonas aeruginosa revealed a conserved distinct m6A pattern that is significantly different from that in eukaryotes. Most m6A peaks are located inside open reading frames (ORF), and carry a unique consensus motif (GCCAU). Functional enrichment analysis of bacterial m6A peaks indicates that the majority of m6A-modified transcripts are associated with respiration, amino acids metabolism, stress response, and small RNAs genes, suggesting potential regulatory roles of m6A in these pathways. m6A profiling in E.coli and P.aeruginosa mRNA
Project description:Chromosomal rearrangements involving ETS factors, ERG and ETV1, occur frequently in prostate cancer. How these factors contribute to tumorigenesis and whether they play similar in vivo roles remain elusive. We show that ERG and ETV1 control a common transcriptional network but in an opposing fashion. In mice with ERG or ETV1 targeted to the endogenous Tmprss2 locus, either factors cooperated with Pten-loss, leading to localized cancer, but only ETV1 supported development of advanced adenocarcinoma, likely through enhancement of androgen receptor signaling and steroid biosynthesis. Indeed, ETV1 expression promotes autonomous testosterone production, which may contribute to tumor progression to castration-resistant prostate cancer. Patient data confirmed association of ETV1 expression with aggressive disease. We conclude that despite many shared targets, ERG and ETV1 contribute differently to prostate tumor biology. Hence, prostate cancers with these fusions should be considered as distinct subtypes for patient stratification and therapy. Genomic targets of ERG and ETV1 transcription factors were identified by antibody-mediated and biotin-mediated ChIP-chip in human VCaP and LNCaP cells, respectively.
Project description:RIP-Chip was performed on DG75-eGFP, DG75-10/12, BCBL-1, BL41, BL41 B95.8 and Jijoye using anti-human Ago2 (11A9) antibodies. Anti-BrdU antibodies were used as controls for DG75-eGFP, DG75-10/12 and BCBL-1. Total RNA was used as control for BL41, BL41 B95.8 and Jijoye. Samples were analyzed on Affymetrix Gene ST 1.0 Arrays (2 independent biological replicates / sample) KSHV, EBV and cellular miRNA targets were determined by RIP-Chip using monoclonal antibodies to human Ago2
Project description:Fragile-X Syndrome (FXS) is a multi-organ disease leading to mental retardation, macro-orchidism in males, and premature ovarian insufficiency in female carriers. FXS is also a prominent monogenic disease associated with autism spectrum disorders (ASD). FXS is typically caused by the loss of FRAGILE X-MENTAL RETARDATION 1 (FMR1) expression, which encodes for the RNA-binding protein (RBP), FMR1 (or FMRP). We report the discovery of the RNA recognition elements (RREs), binding sites, and mRNA targets for wild-type and I304N mutant FMRP isoforms as well as its paralogs, FXR1 and FXR2. RRE frequency, ratio, and distribution determine target mRNA association with FMRP. Among highly-enriched targets, we identified many genes involved in ASD and demonstrate that FMRP can affect their protein levels in cell culture, mice, and human brain. Unexpectedly, we discovered that these targets are also dysregulated in Fmr1-/- mouse ovaries, showing signs of premature follicular overdevelopment. These results indicate that FMRP targets shared signaling pathways across different cellular contexts. As it is become increasingly appreciated that signaling pathways are important to FXS and ASD, our results here provide an invaluable molecular guide towards the pursuit of novel therapeutic targets for these devastating neurological disorders. The mRNA profile of RNA recovered from FLAG-antibody immunoprecipitated FMRP was compared to the mRNA profile of the starting lysate material.
Project description:Corynebacterium glutamicum GlxR is a homolog of the cAMP receptor protein. Although over 200 GlxR binding sites in the C. glutamicum genome are predicted in silico, studies on the GlxR physiological function have been hindered by the severe growth defects of a glxR mutant. This study comprehensively identified the GlxR regulon by chromatin immunoprecipitation in conjunction with microarray (ChIP-chip) analyses. In total, 209 regions were detected as in vivo GlxR binding sites. Moreover, ChIP-chip analyses showed that GlxR was still able to interact with its target sites in a deletion mutant of cyaB, the sole adenylate cyclase gene in the genome, even though binding affinity was markedly decreased. To identify the direct GlxR targets, we immunoprecipitated DNA from a strain expressing a Strep-tag II-tagged GlxR-protein using an anti-Strep-tag II antibody. To investigate effect of depletion of cAMP by deletion of the cyaB gene, which encodes the sole adenylate cyclase in C. glutamicum, on GlxR binding in vivo, we immunoprecipitated DNA from a cyaB deletion strain expressing a Strep-tag II-tagged GlxR-protein using an anti-Strep-tag II antibody. Three or more independent biological replicates were generated in both cases.
Project description:SAGA member Ada2 is required for the majority of H3K9 acetylation in C. neoformans. To identify specific genomic loci that exhibit Ada2-dependent H3K9 acetylation, we performed ChIP-Seq against H3K9ac in wildtype and ada2Δ cells. ChIP-Seq was performed using antibodies for H3K9ac in KN99 wildtype cells and ada2Δ cells. Input and IPed DNA was collected in triplicate from each strain and sequenced on an Illumnina HiSeq 2000 flow cell producing 84 million reads. Due to the lack of quality scores, raw reads are omitted from the submission.
Project description:Bacteria modify expression of different types of terminal oxidase in response to oxygen availability. Corynebacterium glutamicum, a facultative anaerobic bacterium in Actinobacteria, possesses aa3-type cytochrome c oxidase and cytochrome bd-type quinol oxidase, the latter of which is induced upon oxygen limitation. We report here that an extracytoplasmic function sigma factor, SigC, is unprecedentedly responsible for the regulation. Chromatin immunoprecipitation in conjunction with microarray (ChIP-chip) analysis detected eight SigC-binding regions in the genome, leading to identification of a consensus promoter sequence for SigC recognition. The promoter sequences were found upstream of genes for cytochrome bd, heme a synthesis enzymes, and uncharacterized membrane proteins, all of which were upregulated by sigC overexpression. In contrast, that found on the antisense strand upstream of an operon encoding the cytochrome bc1 complex conferred a SigC-dependent negative effect on the operon expression. The SigC regulon was induced by cytochrome aa3 deficiency without modification of expression of sigC itself, but not by deficiency of the bc1 complex. These findings suggest that SigC is activated in response to impairment of electron transfer via cytochrome aa3, not directly to shift in oxygen levels. Our results provide a novel paradigm for transcriptional regulation of the aerobic respiratory system in bacteria. ChIP-chip analyses using a strain expressing the FLAG-tagged SigC in the background of the wild type at two growth phases (exporenatial and stationary phases). Two independent experiments were performed.
Project description:Mixed Lineage Leukemia (MLL) and its metazoan Trithorax orthologs have been linked with the epigenetic maintenance of transcriptional activity. To identify mechanisms by which MLL perpetuates active transcription in dividing cells, we investigated its role during M-phase of the cell cycle. Unlike other chromatin modifying enzymes examined, we found that MLL associates with gene promoters packaged within condensed mitotic chromosomes. Genome-wide location analysis identified a globally rearranged pattern of MLL occupancy during mitosis in a manner favoring genes that were highly transcribed during interphase. Knockdown experiments revealed that MLL retention at gene promoters during mitosis accelerates transcription reactivation following mitotic exit. MLL tethers Menin, RbBP5, and ASH2L to its occupied sites during mitosis, but is dispensable for preserving histone H3K4 methylation. These findings implicate mitotic bookmarking as a component of Trithorax-based gene regulation which may facilitate inheritance of active gene expression states during cell division. anti-MLL ChIP (antibody 456) and anti-pol2 chip (sc-899) in chromatin prepared from interphase and mitotic HeLa cells