Project description:We used the rhesus monkey (Macaca mulatta) as our animal model for the current study with two goals: to characterize the changes in histology and gene expression from early to late gestation (prenatal uterine organogenesis) and to determine if there are effects of prenatal exposure to bisphenol A (BPA) on the developing female uterus. Pregnant rhesus monkeys carrying a female fetus (N=22) were divided into two experimental groups, based on gestational timing: 'early' (N=10) and 'late' (N=12). These groups were then equally sub-divided into control (unexposed) and BPA (exposed) groups (5 Early Control, 5 Early BPA-exposed, 6 Late Control and 6 Late BPA-exposed.) The BPA-exposed monkeys received a deuterated BPA (dBPA, CDN Isotopes, Quebec, Canada) fruit treat on a daily basis, at a dose of 400ug/kg/day). The dosing was aimed at achieving serum levels of BPA detected in adult human biomonitoring studies. The control animals received a vehicle control on a daily basis. The 'early' time period (mid-gestation) referred to gestational days 50-100, approximating the second trimester of human gestation. The fetal monkeys in the 'early' group were delivered via cesarean section on gestation day 100 and euthanized. Samples of maternal and fetal blood and amniotic fluid were obtained. Maternal and fetal weights were also recorded. The 'late' time period referred to gestational days 100-165, approximating the third trimester of human gestation. The fetal monkeys in the 'late' group were delivered vaginally and euthanized. There were five idiopathic stillbirths (2 Control, 3 BPA-exposed) in the late group. Samples of maternal and fetal blood and amniotic fluid were obtained. Maternal and fetal weights were also recorded. After delivery, the fetal uterus was excised and cut sagitally from fundus to cervix; one side was fixed for histological evaluation and the other half was frozen for analysis of gene expression by microarray. The stillbirths were excluded from the microarray.

Project description:Aneuploidy is a hallmark of tumor cells and yet the precise relationship between aneuploidy and a cell’s proliferative ability, or cellular fitness, has remained elusive. In this study we have combined a detailed analysis of aneuploid clones isolated from laboratory-evolved populations of Saccharomyces cerevisiae with a systematic, genome-wide screen for the fitness effects of telomeric amplifications to address the relationship between aneuploidy and cellular fitness. We found that aneuploid clones rise to high population frequencies in nutrient-limited evolution experiments and show increased fitness relative to wild-type. Direct competition experiments confirmed that three out of four aneuploid events isolated from evolved populations were themselves sufficient to improve fitness. To expand the scope beyond this small number of exemplars, we created a genome-wide collection of >1,800 diploid yeast strains each containing a different telomeric amplicon (Tamp) ranging in size from 0.4 to 1,000kb. Using pooled competition experiments in nutrient-limited chemostats followed by high-throughput sequencing of strain-identifying barcodes, we determined the fitness effects of these >1,800 Tamps under three different conditions. Our data revealed that the fitness landscape explored by telomeric amplifications is much broader than that explored by single-gene amplifications. As also observed in the evolved clones, we found the fitness effects of most Tamps to be condition specific with a minority showing common effects in all three conditions. By integrating our data with previous work that examined the fitness effects of single-gene amplifications genome wide, we found that a small number of genes within each Tamp are centrally responsible for each Tamp’s fitness effects. Our genome-wide Tamp screen confirmed that telomeric amplifications identified in laboratory-evolved populations generally increased fitness. Our results show that Tamps are mutations that produce large, typically condition-dependent changes in fitness that are important drivers of increased fitness in asexually evolving populations. Each of these arrays is a Comparative Genomic Hybridization experiment to detect copy number differences between a reference strain and a strain of interest.

Project description:Cancer of the prostate is influenced both by genetic predisposition and environmental factors. The identification of genes capable of modulating cancer development has the potential to unravel disease heterogeneity and aid diagnostic and prevention strategies through improved understanding of gene-environment interactions. To this end, mouse models have been developed to isolate the influences of individual genetic lesions in the context of consistent genotypes and environmental exposures. However, the extent of normal prostatic phenotypic variability dictated by a genetic background potentially capable of influencing the process of carcinogenesis has not been established. In this study we used microarray analysis to quantitate transcript abundance levels in the prostates of five commonly studied inbred mouse strains. We applied a multiclass response t-test to identify genes whose expression in each strain significantly differed from the other four strains. Approximately 13% (932 genes) exhibited significant differential expression (range 1.3 to 190-fold) in one strain relative to other strains (FDRM-bM-^IM-$10%). The pattern of variability in transcript levels did not result from variations unique to a particular strain, but rather represented genetic variability across all five strains assessed. Expression differences were confirmed by qRT-PCR, or immunohistochemistry for several genes previously shown to influence cancer progression such as Psca, Mmp7, and Clusterin. Analyses of human prostate transcripts orthologous to variable murine prostate genes identified differences in gene expression in benign epithelium that correlated with the differentiation state of adjacent tumors. For example, the expression of apolipoprotein D, a gene known to enhance resistance to cell stress in Drosophila, was expressed at significantly greater levels in benign epithelium associated with high-grade versus low-grade cancers. These data support the concept that the cellular, tissue, and organismal context contribute to oncogenesis and suggest that a predisposition to a sequence of events leading to pathology may be determined prior to cancer initiation. Prostates from twelve mice from each of five strains of Mus musculus: C57BL/6J, 129X1/SvJ, BALB/cAnCrl, FVB/NJ and DBA/2NCrl, were resected and individual lobes were dissected: DP: dorsal prostate; LP: lateral prostate; VP: ventral prostate; AP: anterior prostate. Each experimental sample represents a pool of equal amounts of RNA for each prostatic lobe from 3 animals. Four independent experimental samples were created per strain: 12 mice divided into 4 pools of 3 mice each for a total of 4 microarray experiments per strain. Amplified RNA from each experimental sample was hybridized against a reference sample (created by combining equal amounts of RNA from all the samples from all strains) onto custom mouse prostate cDNA microarrays using alternate dye-labeling to account for dye-specific effects.

Project description:Title: Array-based gene expression, CGH and tissue data define a 12q24 gain in neuroblastic tumors with prognostic implication. Background: Neuroblastoma has successfully served as a model system for the identification of neuroectoderm-derived oncogenes. However, in spite of various efforts, only a few clinically useful prognostic markers have been found. Here, we present a framework, which integrates DNA, RNA and tissue data to identify and prioritize genetic events that represent clinically relevant new therapeutic targets and prognostic biomarkers for neuroblastoma. Methods: A single-gene resolution aCGH profiling was integrated with microarray-based gene expression profiling data to distinguish genetic copy number alterations that were strongly associated with transcriptional changes in two neuroblastoma cell lines. FISH analysis using a hotspot tumour tissue microarray of 37 paraffin-embedded neuroblastoma samples and in silico data mining for gene expression information obtained from previously published studies including up to 445 healthy nervous system samples and 123 neuroblastoma samples were used to evaluate the clinical significance and transcriptional consequences of the detected alterations and to identify subsequently activated gene(s). Results: In addition to the anticipated high-level amplification and subsequent overexpression of MYCN, MEIS1, CDK4 and MDM2 oncogenes, the aCGH analysis revealed numerous other genetic alterations, including microamplifications at 2p and 12q24.11. Most interestingly, we identified and investigated the clinical relevance of a previously poorly characterized amplicon at 12q24.31. FISH analysis showed low-level gain of 12q24.31 in 14 of 33 (42%) neuroblastomas. Patients with the low-level gain had an intermediate prognosis in comparison to patients with MYCN amplification (poor prognosis) and to those with no MYCN amplification or 12q24.31 gain (good prognosis) (P = 0.001). Using the in silico data mining approach, we identified elevated expression of five genes located at the 12q24.31 amplicon in neuroblastoma (DIABLO, ZCCHC8, RSRC2, KNTC1 and MPHOSPH9). Among these, DIABLO showed the strongest activation suggesting a putative role in neuroblastoma progression. Conclusions: The presented systematic and rapid framework, which integrates aCGH, gene expression and tissue data to obtain novel targets and biomarkers for cancer, identified a low-level gain of the 12q24.31 as a potential new biomarker for neuroblastoma progression. Furthermore, results of in silico data mining suggest a new neuroblastoma target gene, DIABLO, within this region, whose functional and therapeutic role remains to be elucidated in follow-up studies. High-resolution aCGH was utilized to identify novel genetic alterations in two neuroblastoma cell lines, NGP and IMR-32. Through the integration of gene copy number and gene expression data, the impact of copy number changes on expression levels was determined. Fluorescence in situ hybridization (FISH) on a tissue microarray (TMA) format was used to assess the clinical significance of the identified copy number increase at 12q24.31 in neuroblastoma patients. Finally, we used in silico data mining of publicly available transcriptomics data, to evaluate the transcriptional consequences of the detected 12q24.31 alteration and to identify subsequently activated gene(s). Here, aCGH of the NGP and IMR-32 cell lines was performed. Male genomic DNA was used as reference.

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Proteomics analysis of 2n+x aneuploid yeast

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