Metal tolerance is often a result of metal storage or distribution. Thus, with the goal of advancing the molecular understanding of such metal homeostatic mechanisms, natural variation of metal tolerance in Arabidopsis thaliana was investigated. Substantial variation exists in tolerance of excess copper (Cu), zinc (Zn) and cadmium (Cd). Two accessions, Col-0 and Bur-0, and a recombinant inbred line (RIL) population derived from these parents were chosen for further analysis of Cd and Zn tolerance variation, which is evident at different plant ages in various experimental systems and appears to be genetically linked. Three QTLs, explaining in total nearly 50 % of the variation in Cd tolerance, were mapped. The one obvious candidate gene in the mapped intervals, HMA3, is unlikely to contribute to the variation. In order to identify additional candidate genes the Cd responses of Col-0 and Bur-0 were compared at the transcriptome level. The sustained common Cd response of the two accessions was dominated by processes implicated in plant pathogen defense. Accession-specific differences suggested a more efficient activation of acclimative responses as underlying the higher Cd tolerance of Bur-0. The second hypothesis derived from the physiological characterization of the accessions is a reduced Cd accumulation in Bur-0.
Natural variation in Arabidopsis thaliana Cd responses and the detection of quantitative trait loci affecting Cd tolerance.
Specimen part, Treatment
View SamplesGene copy number variation (CNV) is a form of genetic polymorphism that contributes significantly to genome size and function but remains poorly characterized due to technological limitations. Inter-specific comparisons of CNVs in recently diverged plant species are crucial to uncover selection patterns underlying adaptation of a species to stressful environments. Especially given that gene amplifications have long been implicated in emergence of species-specific traits, we conducted a genome-wide survey to identify species-specific gene copy number expansions and deletions in the model extremophile species - Arabidopsis halleri that has diverged in evolutionarily recent time from Arabidopsis thaliana.
Between-species differences in gene copy number are enriched among functions critical for adaptive evolution in Arabidopsis halleri.
Specimen part
View SamplesPlants often face combinatorial stresses in their natural environment. Here arsenic (As) toxicity was combined with hypoxia (Hpx) in the roots of Arabidopsis thaliana as it often occurs in nature. The present work aimed to explore the effects of single and combined hypoxia and As stress applied at realistic stress levels to hydroponically grown A. thaliana.
Interference between arsenic-induced toxicity and hypoxia.
Specimen part
View SamplesGlobal energy balance in mammals is controlled by the actions of circulating hormones that coordinate fuel production and utilization in metabolically active tissues. Bone-derived osteocalcin, in its undercarboxylated, hormonal form, regulates fat deposition and is a potent insulin secretagogue. Here, we show that insulin receptor (IR) signaling in osteoblasts controls osteoblast development and osteocalcin expression by suppressing the Runx2 inhibitor Twist-2. Mice lacking IR in osteoblasts have low circulating undercarboxylated osteocalcin and reduced bone acquisition due to decreased bone formation and deficient numbers of osteoblasts. With age, these mice develop marked peripheral adiposity and hyperglycemia accompanied by severe glucose intolerance and insulin resistance. The metabolic abnormalities in these mice are improved by infusion of exogenous under-carboxylated osteocalcin. These results indicate the existence of a bone-pancreas endocrine loop through which insulin signaling in the osteoblast ensures osteoblast differentiation and stimulates osteocalcin production, which in turn regulates insulin sensitivity and pancreatic insulin secretion to control glucose homeostasis.
Insulin receptor signaling in osteoblasts regulates postnatal bone acquisition and body composition.
Specimen part, Time
View SamplesThe SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription. Here we analysed the transcription profiles of single and double mutants and wild-type cells by whole-genome microarray analysis. Our results indicate that genome-wide transcriptional misregulation in htz1 can be partially or totally suppressed if SWR1 is not formed (swr1), if it forms but cannot bind to chromatin (swc2), or if it binds to chromatin but has no histone replacement activity (swc5). These results suggest that in htz1 the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter.
The SWR1 histone replacement complex causes genetic instability and genome-wide transcription misregulation in the absence of H2A.Z.
No sample metadata fields
View SamplesThe cascade of molecular events involved in mammalian sex determination has been shown to involve the SRY gene, but specific downstream events have eluded researchers for decades. The current study identifies one of the first direct downstream targets of the male sex-determining factor SRY as the basic-helix-loop-helix (bHLH) transcription factor TCF21. SRY was found to directly associate with the Tcf21 promoter SRY/SOX9 response element both in vitro and in vivo during male sex determination. TCF21 was found to promote an in vitro sex reversal of embryonic ovarian cells to promote precursor Sertoli cell differentiation. Therefore, SRY acts directly on the Tcf21 promoter to, in part, initiate a cascade of events associated with Sertoli cell differentiation and embryonic testis development.
Basic helix-loop-helix transcription factor TCF21 is a downstream target of the male sex determining gene SRY.
Sex, Specimen part, Treatment
View SamplesEmbryonic day 13 (E13), E14, and E16 rat testes and ovaries were used for microarray analysis, as well as E13 testis organ cultures that undergo testis morphogenesis and develop seminiferous cords in vitro. A list of 109 genes resulted from a selective analysis for genes present in male gonadal development and with a 1.5-fold change in expression between E13 and E16. Characterization of these 109 genes potentially important for testis development revealed that cytoskeletal-associated proteins, extracellular matrix factors, and signaling factors were highly represented. Throughout the developmental period (E13-E16), sex-enriched transcripts were more prevalent in the male with 34 of the 109 genes having testis-enriched expression during sex determination. In ovaries, the total number of transcripts with a 1.5-fold change in expression between E13 and E16 was similar to the testis, but none of those genes were both ovary enriched and regulated during the developmental period. Genes conserved in sex determination were identified by comparing changing transcripts in the rat analysis herein, to transcripts altered in previously published mouse studies of gonadal sex determination. A comparison of changing mouse and rat transcripts identified 43 genes with species conservation in sex determination and testis development. Profiles of gene expression during E13-E16 rat testis and ovary development are presented and candidate genes for involvement in sex determination and testis differentiation are identified. Analysis of cellular pathways did not reveal any specific pathways involving multiple candidate genes. However, the genes and gene network identified influence numerous cellular processes with cellular differentiation, proliferation, focal contact, RNA localization, and development being predominant.
Regulation of the gonadal transcriptome during sex determination and testis morphogenesis: comparative candidate genes.
No sample metadata fields
View SamplesThe current study investigates the direct effects of in utero vinclozolin exposure on the developing rat testis transcriptome. Vinclozolin is a commonly used fungicide in agriculture and is an endocrine disruptor with anti-androgenic activity. Previous studies have demonstrated that exposure to vinclozolin during embryonic gonadal sex determination induces epigenetic modifications of the germ line and transgenerational adult onset disease states that include spermatogenic cell defects, prostate disease, kidney disease, and tumor development. An investigation of the molecular actions of vinclozolin was initiated through an analysis of direct actions on the F1 generation embryonic testis development. Microarray analyses were performed to compare control and vinclozolin treated testis transcriptomes at embryonic day 13, 14 and 16. A total of 576 differentially expressed genes were identified and the major cellular functions and pathways associated with these altered transcripts were examined. The sets of regulated genes at the different development periods were found to be transiently altered and distinct. Interestingly, genes previously shown to be regulated during normal male sex determination were not altered by vinclozolin treatment. Categorization by major known functions of all 576 genes altered by in utero vinclozolin exposure demonstrates transcription, signaling, cytoskeletal and extra cellular matrix associated transcripts are highly represented. Specific cellular process and pathway analyses suggest the involvement of Wnt and calcium signaling, vascular development and epigenetic mechanisms as potential mediators of the direct F1 generation actions of vinclozolin.
Alterations in the developing testis transcriptome following embryonic vinclozolin exposure.
Sex, Specimen part
View SamplesThe fermentable carbohydrate composition of wort and the manner in which it is utilised by yeast during brewery fermentation has a direct influence on fermentation efficiency and quality of the finished product. In this study the response of a brewing yeast strain to changes in wort fermentable carbohydrate concentration and composition during full-scale (3275 hL) brewery fermentation was investigated by measuring transcriptome changes with the aid of oligonucleotide based DNA arrays. Up to 90% of the detectable genes showed a significant (P 0.05) differential expression pattern during fermentation and the majority of these genes showed either transient or prolonged peaks in expression following the exhaustion of the monosaccharides glucose and fructose from the wort. Those which did not display this apparent carbon catabolite derepression response were mainly those genes involved in cytokinesis and cell budding, which had higher expression values during active growth of cells. Transcriptional activity of many genes was consistent with their known responses to glucose de/repression under laboratory conditions, despite the presence of di- and trisaccharide sugars in the wort.
AtEnsEMBL.
No sample metadata fields
View SamplesSV7tert AML cells were obtained from ATCC and cultured in Dulbecco's modified essential medium (DMEM), glutamine (4mmol) and 10% foetal bovine serum (FBS). Two million SV7tertAML cells were subcutaneously injected into nude mice either with or without subcutaneous oestrogen pellets (n=4 per group); oestrogen was added using 0.36mg 60 day release oestrogen pellets implanted sub-cutaneously. Mice were housed in pathoflex isolators at 26C, on 12 hour light / dark cycles. Irradiated RB2 diet and autoclaved water provided ad libertum.
Analysis of the oestrogen response in an angiomyolipoma derived xenograft model.
Specimen part
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