Project description:This SuperSeries is composed of the following subset Series: GSE26895: Drosophila LID RNAi gene expression profiling GSE27078: LID ChIP-Seq in wild type, and H3K4me3 ChIP-Seq in wild type and lid RNAi Drosophila melanogaster GSE40599: POLIISER5 and POLIISER2 ChIP-Seq in mutant RNAi LID Drosophila Melanogaster Refer to individual Series
Project description:Chd1 is a conserved ATP-dependent chromatin remodeler that maintains the nucleosomal structure of chromatin, but the determinants of its specificity and its impact on gene expression are not well defined. To identify the determinants of Chd1 binding specificity in the yeast genome, we investigated Chd1 occupancy in mutants of several candidate factors. We found that several components of the PAF1 transcription elongation complex contribute to Chd1 recruitment to highly transcribed genes, and identified Spt4 as a factor that appears to negatively modulate Chd1 binding to chromatin. We discovered that CHD1 loss alters H3K4me3 and H3K36me3 patterns throughout the yeast genome. Interestingly, the aberrant histone H3 methylation patterns were predominantly observed within 1 kb from the transcription start site, where both histone H3 methylation marks co-occur. A reciprocal change between the two marks was obvious in the absence of Chd1, suggesting a role for CHD1 in establishing or maintaining the boundaries of these largely mutually exclusive histone marks. Strikingly, intron-containing genes were most susceptible to CHD1 loss, and exhibited a high degree of histone H3 methylation changes. Intron retention was significantly lower in the absence of CHD1, suggesting that CHD1 function as a chromatin remodeler could indirectly affect RNA splicing. This SuperSeries is composed of the SubSeries listed below. Overall design: Refer to individual Series
Project description:We report genome-wide Chd1 occupancy in WT and in ten elongation factor mutants, and genome-wide H3K4me3/H3K36me3 profiles in WT and CHD1 mutant. Overall design: ChIP-seq for Chd1 in wild-type and in ten elongation factor mutants. ChIP-seq for H3K4me3/H3K36me3 in wild-type and CHD1 mutant.
Project description:Investigation of 5' transcripts using strand specific sequencing for T. maritima under logphase, maltose minimal media growth conditions Overall design: Two replicate samples were sequenced after isolating total RNA of cultures grown in maltose minimal media. Cells were harvested in logphase growth.
Project description:We have designed a zebrafish genomic microarray to identify DNA-protein interactions in the proximal promoter regions of over 11,000 zebrafish genes. Using these microarrays, together with chromatin immunoprecipitation with an antibody directed against tri-methylated lysine 4 of Histone H3, we demonstrate the feasibility of this method in zebrafish. This approach will allow investigators to determine the genomic binding locations of DNA interacting proteins during development and expedite the assembly of the genetic networks that regulate embryogenesis. Genomic array design Microarrays were designed as described below and manufactured by Agilent Technologies (www.agilent.com). Further information on design can be found at http://jura.wi.mit.edu/bioc/gbell/zfish_chip/. Selection of transcription start sites and identification of promoter sequences We interrogated 5 databases: Ensembl, VEGA, Refseq, ZGC full length clones and a database provided by Dr. Leonard Zon (Harvard Medical School, Boston, USA) in order to assemble an extensive list of zebrafish transcripts. The Zon lab database is a hand-curated database of zebrafish genes that have homologues in other species. We included all transcripts that appeared in the manually annotated databases (VEGA, Zon) and in the ZGC full length database. We also identified genes present in any 2 of the 5 databases and included those not already selected. The transcripts were mapped to the zebrafish genome (Zv4, June 2004) obtained from UCSC Bioinformatics (http://genome.ucsc.edu) and the transcription start site (TSS) for each transcript was determined. Transcripts with TSSs within 500bp were clustered into a transcriptional unit (TU) and promoter regions were identified relative to the most upstream TSS. This resulted in the identification of 13,413 TUs and corresponding promoter regions. Each promoter region was extracted and masked for repetitive sequence by RepeatMasker. If the promoter region contained a gap the upstream sequence was also masked. Information on the transcriptional units that were included in the final design can be found at http://jura.wi.mit.edu/bioc/gbell/zfish_chip/. Selection of oligonucleotides 60-mer oligonucleotide probes representing the region between 1.5kb upstream and 0.5kb downstream of the annotated TSS of each transcriptional unit were then designed. Although transcription factors and other DNA binding proteins are known to regulate genes from distances of greater than -1.5kb or + 0.5kb, much information can be gained from regions close to the TSS , and the H3K4Me3 mark studied in this paper is found at the most 5’ end of a gene, close to the TSS. Selection of 60-mers for the microarrays was essentially as described in  using the Zv4 build of the zebrafish genome and a locally customized version of ArrayOligoSelector. 60-mers were chosen so that promoter regions contained approximately one probe every 250bp with a maximum distance between probes for each promoter region set at 600bp. In cases where only one probe could be designed for a particular TU these were not included in the final design. This process yielded 80,839 probes for 11,171 promoter regions We also incorporated several sets of control probes, both positive and negative. On each array there are 1090 probes designed against ‘gene desert’ regions, which are genomic regions that are unlikely to be bound by transcriptional regulators, and 270 probes designed against Arabidopsis thaliana genes, which are not present in the zebrafish genome (by BLAST). In addition, because our main motivation for making these microarrays is to identify mesodermally-regulated genes we included 7 genes expressed in mesoderm during gastrulation as positive controls (wnt11, flh, vent, msgn1, myod, fgf8, pcdh8). Probes designed against these promoters, which flank from 3-4kb around each TSS, are arrayed 2-4 times on each slide. Since these genes are expressed at gastrula stages to varying degrees, they also serve as a positive controls in this study. Finally there are 2256 controls added by Agilent and a variable number of blank spots. These probes were divided between two microarray slides each with 44,290 features. We refer to these two microarray slides as the ‘proximal promoter set’. A proximal promoter set based on these designs as well as an expanded set of 9 slides which contain regions from –9kb to + 3kb relative to the TSS, are available by contacting Agilent (www.agilent.com) or by downloading the design files from http://jura.wi.mit.edu/bioc/gbell/zfish_chip/ for self-manufacture.
Project description:RNA-Seq is an effective method to study the transcriptome, but specialized methods are required to identify the 5' ends of transcripts. Several methods have been published for this specific purpose, but their relative merits have not been systematically analyzed. Here, we directly compare the performance of five such methods with cellular RNA as well as a novel spike-in RNA assay that provides a solution to issues in interpreting results arising from uncertainties in annotation or RNA processing. Using a single human RNA sample, we constructed and sequenced ten libraries with these methods and one standard RNA-Seq library as control. We find that the CAGE method performed best and that most of its unannotated peaks are supported by evidence from other genomic methods. We applied the CAGE method to eight brain-related samples and revealed sample-specific TSS usage as well as a transcriptome-wide pattern in TSS usage.
Project description:This SuperSeries is composed of the following subset Series: GSE36200: RAMPAGE dataset for the human K562 cell line GSE36212: Promoter activity profiling throughout the Drosophila life cycle reveals role of transposons in regulatory innovation Refer to individual Series
Project description:Investigation of 5' transcripts using strand specific sequencing for T. maritima under logphase, maltose minimal media growth conditions Two replicate samples were sequenced after isolating total RNA of cultures grown in maltose minimal media. Cells were harvested in logphase growth.