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: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:Expressed sequence tags (EST)-based microarrays are powerful tools for gene discovery and signal transduction studies in a small number of well-characterized species. To explore the usefulness of this technique for poorly characterized species, we have hybridized the 11 522-element Arabidopsis microarrays with labeled cDNAs from mature leaf and shoot apices from several different species. Expression of 23 to 47% of the genes on the array was detected, demonstrating that a large number of genes from distantly related species can be surveyed on Arabidopsis arrays. Differential expression of genes with known functions was indicative of the physiological state of the tissues tested. Genes involved in cell division, stress responses, and development were conserved and expressed preferentially in growing shoots. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
Project description:Five allotetraploid cotton species have adapted, through their transcriptional responses, to unique environments with distinct levels of inherent abiotic stresses. The transcriptional responses of leaf and root tissue in five allotetraploid cotton species (Gossypium hirsutum, G. barbadense, G. tomentosum, G. mustelinum, and G. darwinii) under salt stress have been investigated in this study using cotton long oligonucleotide microarrays. Physiological responses to salinity such as stomatal conductance, ion and osmoprotectant contents were also measured as indicators of imposed stress. Accessions from these five cotton species were hydroponically grown and gradually introduced to a NaCl treatment (15 dS m-1). The microarray results identified 2721 and 2460 differentially expressed genes under salt stress that were significant in leaf and root tissue, respectively. Many of these genes were classified under gene ontology (GO) categories that suggest abiotic stress. These allotetraploid cottons shared transcriptional responses to salinity, but also showed responses that were species-specific. No consistent differences in transcriptional response among the previously estimated phylogenetic branches were found. Stomatal conductance, ion accumulation, and betaine, trigonelline, and trehalose contents also indicated salt stress. This global assessment of transcriptional and physiological responses to salt stress of these cotton species may identify possible gene targets for crop improvement and evolutionary studies of cotton. Keywords: CEGC Cotton oligo salt stress The transcriptional responses of leaf and root tissue in five allotetraploid cotton species (Gossypium hirsutum, G. barbadense, G. tomentosum, G. mustelinum, and G. darwinii) under salt stress have been investigated in this study using cotton long oligonucleotide microarrays. Physiological responses to salinity such as stomatal conductance, ion and osmoprotectant contents were also measured as indicators of imposed stress. Accessions from these five cotton species were hydroponically grown and gradually introduced to a NaCl treatment (15 dS m-1).
Project description:This set includes individuals from 10 different primate species whose genomic DNA was used in an array-based comparative genomic hybridization (aCGH)using human cDNA microarrays to detect gene copy number variation across 10 primate species. An organism part comparison experiment design type compares tissues, regions, organs within or between organisms. Keywords: organism_part_comparison_design, array CGH Computed
Project description:Given that gene duplication is a major driving force of evolutionary change and the key mechanism underlying the emergence of new genes and biological processes, this study sought to use a novel genome-wide approach to identify genes that have undergone lineage-specific duplications or contractions among several hominoid lineages. Interspecies cDNA array-based comparative genomic hybridization was used to individually compare copy number variation for 39,711 cDNAs, representing 29,619 human genes, across five hominoid species, including human. We identified 1,005 genes, either as isolated genes or in clusters positionally biased toward rearrangement-prone genomic regions, that produced relative hybridization signals unique to one or more of the hominoid lineages. Measured as a function of the evolutionary age of each lineage, genes showing copy number expansions were most pronounced in human (134) and include a number of genes thought to be involved in the structure and function of the brain. This work represents, to our knowledge, the first genome-wide gene-based survey of gene duplication across hominoid species. The genes identified here likely represent a significant majority of the major gene copy number changes that have occurred over the past 15 million years of human and great ape evolution and are likely to underlie some of the key phenotypic characteristics that distinguish these species. A species experiment design type assays differences between distinct species. Using regression correlation, arrayCGH, acCGH
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:Transcriptional abundance in each of senescent populations from two post-selection HMEC lines (48R and 184) is compared with abundance in isogenic early passage proliferating cells and also with abundance in early passage quiescent cells. A strain or line experiment design type assays differences between multiple strains, cultivars, serovars, isolates, lines from organisms of a single species. Computed
Project description:Transcriptional abundance in each of senescent populations from three cell lines (WS1, WI38 and BJ) is compared with abundance in isogenic early passage proliferating cells and also with abundance in early passage quiescent cells. A strain or line experiment design type assays differences between multiple strains, cultivars, serovars, isolates, lines from organisms of a single species. Computed
Project description:Little is known about the extent of genetic variability among Entamoeba strains and potential genotypic associations with virulence. Variable phenotypes have been identified for Entamoeba strains. E. histolytica is invasive and causes colitis and liver abscesses, but only in 10% of infected individuals; 90% of subjects remain asymptomatically colonized. E. dispar, a closely related species, appears to be incapable of causing invasive disease. In order to determine the extent of genetic diversity among Entamoeba strains we have developed an E. histolytica genomic DNA microarray and used it to genotype strains of E. dispar and E. histolytica. Based on the identification of divergent genetic loci, all six strains (four EH and two ED) had unique genetic fingerprints. Genomic regions with unusually high levels of divergence were identified indicating that structural or evolutionary pressures are molding selective regions of the Entamoeba genome. Comparison of divergent genetic regions allowed us to readily distinguish between EH and ED, identify novel genetic regions that may be used for strain and species typing, and identity a number of novel potential virulence determinants. Among these are Androgen Inducible Gene1, a CXXC receptor kinase, a peroxiredoxin 1-related gene, a Ras family member gene, a Rab geranylgeranyltransferase, and a gene with a UPF0034 domain. Among the four EH strains, an avirulent strain EH (Rahman) was the most divergent and phylogenetically distinct raising the intriguing possibility that genetic subtypes of E. histolytica may be at least partially responsible for the observed variability in clinical outcomes. Our approach shows the utility of a microarray-based genotyping assay to identify genetic variability between Entamoeba isolates and can readily be applied to the study of clinical isolates. A genotyping experiment design type classifies an individual or group of individuals on the basis of alleles, haplotypes, SNP's. User Defined