Project description:We mapped Tetrahymena macronuclear replication origins on a genome-wide scale using Okazaki fragments sequencing (OK-seq). OK-seq permits a high-resolution, quantitative analysis of replication fork initiation on a genome-wide scale that is dependent on the depth of coverage within a population of molecules. Replication initiation sites of the TXR1 (Histone H3 K27 monomethyltranferase) deletion strain were also studied compare to wild type using OK-seq.
Project description:We mapped Tetrahymena macronuclear replication origins in TXR1 overexpression strain on a genome-wide scale using Okazaki fragments sequencing (OK-seq). Replication initiation sites of TXR1 overexpression strain followig cadmium induction of MMT1 promoter driven-TXR1 were studied compare to the uninduced TXR1 overexpression strain without cadmium using OK-seq.
Project description:Genome-wide analysis of replication initiation in a TXR1 (Histone H3 K27 monomethyltranferase) overexpression strain in Tetrahymena
Project description:Via the deep-sequencing of Okazaki fragments from Saccharomyces cerevisiae, we report the first comprehensive documentation of genome-wide replication directionality in any eukaryote; this permits the systematic analysis of both replication initiation and termination. We conduct a genome-wide analysis of origin competence and efficiency, and conclude that the majority of origins are competent to fire in each cell cycle and generally do so with high efficiency. Additionally, the spatial resolution of our data allow us to determine that leading-strand initiation generally occurs within the nucleosome-free region at origins. Using a strain in which late origins can be induced to fire early, we show that replication termination is a largely passive phenomenon that does not rely on cis-acting sequences or replication fork pausing and that the replication profile is determined largely by the kinetics of origin firing, allowing us to reconstruct chromosome-wide timing profiles from an asynchronous culture.
Project description:Via the deep-sequencing of Okazaki fragments from Saccharomyces cerevisiae, we report the first comprehensive documentation of genome-wide replication directionality in any eukaryote; this permits the systematic analysis of both replication initiation and termination. We conduct a genome-wide analysis of origin competence and efficiency, and conclude that the majority of origins are competent to fire in each cell cycle and generally do so with high efficiency. Additionally, the spatial resolution of our data allow us to determine that leading-strand initiation generally occurs within the nucleosome-free region at origins. Using a strain in which late origins can be induced to fire early, we show that replication termination is a largely passive phenomenon that does not rely on cis-acting sequences or replication fork pausing and that the replication profile is determined largely by the kinetics of origin firing, allowing us to reconstruct chromosome-wide timing profiles from an asynchronous culture. 5 samples are included. Two are replicate, paired-end, wild-type samples sequenced via Illumina methodology. The raw data for these two are also deposited in the GEO repository under accession numbers GSM835650 and GSM835651. Two replicate, single-end, Sld2, Sld3, Dbf4, Dpb11, Cdc45 and Sld7 (SSDDCS) overexpression via galactose induction experiments are reported sequenced via Ion Torrent methodology. One single-end, Sld2, Sld3, Dbf4, Dpb11, Cdc45 and Sld7 (SSDDCS) normal expression control via glucose media experiment is reported sequenced via Ion Torrent methodology.
Project description:DNA replication must be tightly controlled during each cell cycle to prevent unscheduled replication and ensure proper genome maintenance. The currently known controls that prevent re-replication act redundantly to inhibit pre-Replicative Complex (pre-RC) assembly outside of the G1 phase of the cell cycle. We have analyzed the effects of re-replication on the S. cerevisiae genome using a combination of Comparitive Genomic Hybridization (CGH) of re-replicating strains and Genome-Wide Location Analysis of pre-RC components. These data indicate which sites in the genome assemble pre-RCs under re-replication conditions, which sites undergo re-initiation and the extent of re-replication. Keywords: comparative genomic hybridization, ChIP-chip, re-replication, DNA replication, pre-RC
Project description:Four genome wide microarrays containing the predicted coding sequences (putative genes) for the ciliated protozoan Tetrahymena thermophila used to study gene expression in starved cells (Starvation 0 hour and Starvation 9 hour, each two replicates). Combined these four microarrays with 50 microarrays described in Miao et al (2009, PMID: 19204800; GSE11300) and other 13 microarrays, we constructed the Tetrahymena gene network (TGN) using three methods: the Pearson correlation coefficient, the Spearman correlation coefficient and the context likelihood of relatedness (CLR) algorithm. The accuracy and coverage of the three networks were evaluated using four conserved protein complexes in yeast, and the CLR network was found to be the best network, with a Z-score threshold 3.49. Then the TGN was partitioned, and 55 modules were found. In addition, analysis for the arbitrarily determined 1200 hubs showed that these hubs could be sorted into six groups according to expression profiles. We also investigated human disease orthologs in Tetrahymena that are missing in yeast and found evidence indicating that some of these were involved in the same process in Tetrahymena as in human.
Project description:Two genome-wide microarrays containing the predicted coding sequences (putative genes) for the ciliated protozoan Tetrahymena thermophila were used to study gene expression in starved cells (starvation 0 hour and starvation 24 hour). Combining these two microarrays with 50 microarrays described in Miao et al. (2009) and 15 other microarrays, we constructed the Tetrahymena gene network (TGN) using three methods: the Pearson correlation coefficient, the Spearman correlation coefficient and the context likelihood of relatedness (CLR) algorithm. The accuracy and coverage of the three networks were evaluated using four conserved protein complexes in yeast, and the CLR network was found to be the best network, with a Z-score threshold 3.49. Then the TGN was partitioned, and 55 modules were found. In addition, analysis for the arbitrarily determined 1200 hubs showed that these hubs could be sorted into six groups according to expression profiles. We also investigated human disease orthologs in Tetrahymena that are missing in yeast and found evidence indicating that some of these were involved in the same process in Tetrahymena as in human.