ABSTRACT: Telomeres and the protein/RNA complexes involved in maintaining them are rapidly evolving systems across eukaryotes. Using two Saccharomyces species, S. cerevisiae and S. bayanus, we provide evidence that the telomere systems of these two closely related yeasts have evolved significantly apart and that the gene in one species can not maintain the set-point of telomere length of the other species in the hybrid. Each array has co-hybridized RNA vs DNA for the indicated species (BB9=S. bayanus, CC5=S. cerevisiae) or hybrid (BC11). The cultures for RNA preparation were grown to midlog phase at the indicated temperature.
SUBMITTER: Douglas Koshland Yixian ZhengMaitreya J DunhamOna MartinMaitreya J. DunhamChristopher DeSevoBenjamin Guo
Project description:Technological advances now make gene expression analysis feasible in any sequenced organism, and new sequencing methods have greatly accelerated genome sequencing. Here we show that important insights into gene function are possible by comparing gene expression response to genetic and environmental perturbations between related species. We present a gene expression compendium designed for maximal gene expression variation in the sensu stricto yeast Saccharomyces bayanus. While many aspects of gene expression are conserved over the 20 million years of evolution separating S. bayanus from the model yeast S. cerevisiae, we observe regulatory changes, including in galactose metabolism and sporulation. The expression data also allows us to predict the biological roles of genes unique to S. bayanus, leading us to propose a role in oxidative stress response for a group of genes, and also to identify a regulatory network specific to this yeast. This dataset contains 53 experiments as follows: (experiment: number of datasets (number of arrays)) growth at different temperatures: 1 (3) heat shock: 4 (18) ammonium: 1 (6) cadmium: 1 (4) copper: 1 (6) lead: 1 (6) nickel: 1 (5) sulfite toxicity: 1 (6) zinc: 1 (6) ethanol toxicity: 1 (6) sorbitol: 1 (6) bleach: 1 (6) hydrogen peroxide: 3 (17) 2-deoxyglucose: 1 (6) hydroxyurea: 1 (6) lovastatin: 1 (4) MG-132: 1 (5) MMS: 1 (6) rapamycin: 1 (6) tunicamycin: 1 (6) zeocin: 1 (6) chronological aging: 3 (13) diauxic shift: 1 (6) galactose: 5 (38) glycerol: 1 (4) sucrose: 1 (4) auxotroph starvation: 1 (11) nutrient limited chemostat growth: 3 (7) mating type and ploidy: 1 (3) alpha factor: 1 (8) cell cycle: 1 (30) sporulation: 3 (18) strain backgrounds: 1 (4) cross progeny: 1 (22) Tn7 insertions: 1 (27) 555.11 and 670.20 knockout tetrads: 2 (8) Timecourse datasets: heat shock, ammonium, cadmium, copper, lead, nickel, sulfite toxicity, zinc, ethanol toxicity, sorbitol, bleach, hydrogen peroxide, 2-deoxyglucose, hydroxyurea, lovastatin, MG-132, MMS, rapamycin, tunicamycin, zeocin, chronological aging, diauxic shift, galactose, glycerol, sucrose, auxotroph starvation, alpha factor, cell cycle, sporulation Single timepoint datasets: growth at different temperatures, strain backgrounds, cross progeny, Tn7 insertions, nutrient limited chemostat growth, mating type and ploidy, 555.11 and 670.20 knockout tetrads Almost all samples were hybridized versus a common reference prepared from a mixture of RNA from Mat a, Matx, and Mata/x cells sampled in both exponential and stationary phase. Additionally, RNA from stress conditions was included: hydrogen peroxide treatment sampled at 10, 30 and 45 minutes, and heat shock from 25 to 37 degrees sampled at 10 and 30 minutes. Samples from the following datasets were not hybridized versus the common reference (reference used in parenthesis and in array annotations): cell cycle (asynchronous culture), constant temperatures (log phase culture), mating type and ploidy (log phase culture), diauxic shift (log phase culture), and strain backgrounds (log phase culture). Replicates and dye swaps were not used.
Project description:In order to further our understanding of the metabolic network of the malaria parasite, Plasmodium falciparum, we carried out a concurrent transcriptomic and metabolomic study of the parasite's intraerythrocytic developmental cycle. These microarray data were generated to compare the expression levels of metabolic enzymes to the concentrations of their associated metabolites over the 48-hour life cycle. Sorbitol-synchronized Plasmodium falciparum (3D7 strain) was grown in tissue culture flasks in incubators according to standard protocols. Immediately after reinvasion, and at 8-hour intervals thereafter, parasites were harvested by centrifugation. For each timepoint, 0.5 mL of packed RBC (10% parasitemia) was pelleted by centrifugation, washed once in PBS and flash-frozen in liquid nitrogen. Total RNA isolation and amino-allyl cDNA labeling were as previously described (Bozdech et al., 2003). A pool of 3D7 total RNA from all intraerythrocytic developmental stages was generated and used as the reference sample. For DNA microarray hybridization, pool cDNA was coupled to Cy3 dye, while cDNA from an individual timepoint was coupled to Cy5 dye. DNA microarrays were scanned using an Axon 4200A scanner and images analyzed using Axon GenePix software (Axon Instruments, Union City, CA, USA). Microarray data were stored and analyzed using our in-house database PUMAdb (Princeton University MicroArray database). All data for individual arrays were normalized by a global normalization using unflagged features with >= 65% of pixels one or more standard deviations over local background. All unflagged spots were selected and extracted for further analysis. Data were filtered to remove oligos more than 1 datapoint missing across the timeseries, log2 transformed, mean centered, ordered by the timing of their peak expression level, and visualized with Java Treeview (Saldanha, 2004) (Table S3).
Project description:We used microarrays to identify genes regulated by HCF-1 in a daf-16-dependent manner. Samples from young adult worms were hybridized to Agilent microarrays to identify genes differentially expressed in hcf-1(pk924)/daf-16(mgDf47);hcf-1(pk924) and compared to hcf-1(pk924)/N2 arrays.
Project description:Aims: We performed an analysis of maltotriose utilization by 52 Saccharomyces yeast strains able to ferment maltose efficiently and correlated the observed phenotypes with differences in the copy number of genes possibly involved in maltotriose utilization by yeast cells. Methods and Results: The analysis of maltose and maltotriose utilization by laboratory and industrial strains of the species Saccharomyces cerevisiae and Saccharomyces pastorianus (a natural S. cerevisiae/Saccharomyces bayanus hybrid) was carried out using microscale liquid cultivation, as well as in aerobic batch cultures. All strains utilize maltose efficiently as a carbon source, but three different phenotypes were observed for maltotriose utilization: efficient growth, slow/delayed growth and no growth. Through microarray karyotyping and pulsed-field gel electrophoresis blots, we analysed the copy number and localization of several maltose-related genes in selected S. cerevisiae strains. While most strains lacked the MPH2 and MPH3 transporter genes, almost all strains analysed had the AGT1 gene and increased copy number of MALx1 permeases. Conclusions: Our results showed that S. pastorianus yeast strains utilized maltotriose more efficiently than S. cerevisiae strains and highlighted the importance of the AGT1 gene for efficient maltotriose utilization by S. cerevisiae yeasts. Significance and Impact of the Study: Our results revealed new maltotriose utilization phenotypes, contributing to a better understanding of the metabolism of this carbon source for improved fermentation by Saccharomyces yeasts. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc.
Project description:ABSTRACT Background. Acute Kawasaki disease (KD) is difficult to distinguish from other acute rash/fever illnesses, in part because the etiologic agent(s) and pathophysiology remain poorly characterized. As a result, diagnosis and critical therapies may be delayed. Methods. We used DNA microarrays to identify possible diagnostic features of KD. We compared gene expression patterns in the blood of 23 children with acute KD and 18 age-matched febrile children with three illnesses that resemble KD. Results. Genes associated with platelet and neutrophil activation were expressed at higher levels in KD patients than in patients with acute adenovirus infections or systemic adverse drug reactions but not in patients with scarlet fever; genes associated with B cell activation were also expressed at higher levels in KD patients than in controls. A striking absence of interferon-stimulated gene expression in the KD patients was confirmed in an independent cohort of KD subjects. We successfully predicted the diagnosis in 21 of 23 KD patients and 7 of 8 adenovirus patients using a set of 38 gene transcripts. Conclusions. These findings provide insight into the molecular features that distinguish KD from other febrile illnesses, and support the feasibility of developing novel diagnostic reagents for KD based on the host response. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Disease State: One of Kawasaki Disease (KD) or control (C) of Scarlet fever (C-sf), adenovirus infection (C-ai) or drug reaction (C-dr) disease_state_design
Project description:This SuperSeries is composed of the following subset Series: GSE4335: Norway/Stanford Breast Tumors GSE4336: Breast Tumors Abstract: Characteristic patterns of gene expression measured by DNA microarrays have been used to classify tumors into clinically relevant subgroups. In this study, we have refined the previously defined subtypes of breast tumors that could be distinguished by their distinct patterns of gene expression. A total of 115 malignant breast tumors were analyzed by hierarchical clustering based on patterns of expression of 534 "intrinsic" genes and shown to subdivide into one basal-like, one ERBB2-overexpressing, two luminal-like, and one normal breast tissue-like subgroup. The genes used for classification were selected based on their similar expression levels between pairs of consecutive samples taken from the same tumor separated by 15 weeks of neoadjuvant treatment. Similar cluster analyses of two published, independent data sets representing different patient cohorts from different laboratories, uncovered some of the same breast cancer subtypes. In the one data set that included information on time to development of distant metastasis, subtypes were associated with significant differences in this clinical feature. By including a group of tumors from BRCA1 carriers in the analysis, we found that this genotype predisposes to the basal tumor subtype. Our results strongly support the idea that many of these breast tumor subtypes represent biologically distinct disease entities. Refer to individual Series
Project description:Helicobacter pylori infects the stomachs of half of all humans. It has a relatively benign relationship with most hosts, but produces severe pathology, including gastric cancer, in others. Identifying the relative contributions of host, microbial and environmental factors to the outcome of infection has been challenging. Here, we describe one approach for identifying microbial genes that affect the magnitude of host responses to infection. Single colony purified H. pylori isolates were obtained from 25 cases and 71 controls in a Swedish case-control study of gastric cancer. Strains were first phenotyped based on their ability to produce adhesins that recognize two classes of human gastric epithelial receptors. Thirteen binding strains and two non-binding controls were then subjected to whole genome genotyping using H. pylori DNA microarrays. A cohort of 'variable' genes was identified based on a microarray-determined call of 'absent' in at least one member of the strain panel. Each strain was subsequently introduced into two types of germ-free transgenic mice, each programmed to express a different host factor postulated to pose increased risk for development of severe pathology. Expression of biomarkers of host defense was quantitated 4 weeks after inoculation and magnitude of the response correlated with bacterial genotype. The proportion of genes encoding HsdS homologs (specificity subunit of hetero-oligomeric type I restriction-modification systems) was significantly higher in the pool of 18 variable genes whose presence directly correlated with a robust host response than their proportion in the remaining 352 members of the variable gene pool. This suggests that the functions of these HsdS homologs may include control of expression of microbial determinants that affect the extent of gastric responses to this potentially virulent pathogen. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
Project description:Schaner M., et al.; Mol Biol Cell. 2003 Nov;14(11):4376-86. Figure 1 Unsupervised hierarchical clustering of ovarian cell lines and ovarian cancers. Cell lines were not co-clustered with the tumor specimens, because these cell lines have a very prominent proliferation cluster (Perou et al., 1999; Ross et al., 2000) that significantly influences the clustering of the tumor samples if the two sample sets are not analyzed separately. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
Project description:Characterization of patterns of gene expression measured by cDNA microarrays to subclassify tumors into clinically relevant subgroups. In this study, we have refined the previously defined subtypes of breast tumors that could be distinguished by their distinct patterns of gene expression. A total of 115 malignant breast tumors and 7 benign tissues were analyzed by hierarchical clustering based on patterns of expression of 534 "intrinsic" genes and shown to subdivide into a basal epithelial-like, an ERBB2-overexpressing, two luminal epithelial-like and a normal breast tissue-like subgroup. The genes used for classification were selected based on their similar expression levels between pairs of consecutive samples taken from the same tumor separated by 15 weeks of neoadjuvant treatment. A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Computed
Project description:Helicobacter pylori enhances the risk for ulcer disease and gastric cancer, yet only a minority of H. pylori-colonized individuals develop disease. We examined the ability of two H. pylori isolates to induce differential host responses in vivo or in vitro, and then used an H. pylori whole genome microarray to identify bacterial determinants related to pathogenesis. Gastric ulcer strain B128 induced more severe gastritis, proliferation, and apoptosis in gerbil mucosa than did duodenal ulcer strain G1.1, and gastric ulceration and atrophy occurred only in B128+ gerbils. In vitro, gerbil-passaged B128 derivatives significantly increased IL-8 secretion and apoptosis compared with G1.1 strains. DNA hybridization to the microarray identified several strain-specific differences in gene composition including a large deletion of the cag pathogenicity island in strain G1.1. Partial and complete disruption of the cag island in strain B128 attenuated induction of IL-8 in vitro and significantly decreased gastric inflammation in vivo. These results indicate that the ability of H. pylori to regulate epithelial cell responses related to inflammation depends on the presence of an intact cag pathogenicity island. Use of an H pylori whole genome microarray is an effective method to identify differences in gene content between H. pylori strains that induce distinct pathological outcomes in a rodent model of H. pylori infection. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed