Project description:Comparison of expression in liver samples of human, chimp, orang and rhesus, by using a novel multi-species cDNA array Keywords: other
Project description:The determinants of the genetic complexity of Glioblastoma are poorly understood. We generated murine Glioblastomas by transforming glial progenitors in the adult brain with PDGF expression and PTEN deletion +/- p53 deletion. PDGF+PTEN-/- tumors developed additional deletions of specific genes in up to 100% of the tumors, whereas PDGF+PTEN-/-p53-/- tumors did not. Cross-species comparison with data from tCGA database and published in Verhaak, 2010, showed that consistent genetic deletions observed in mouse tumors were specific to human Proneural Glioblastoma. These findings show that the genetic alterations that accumulate during tumor progression are determined by the initiating genetic alterations and by the cellular context in which they occur.
Project description:Abstract Background: One of the approaches for conducting genomics research in organisms that do not yet have a proper microarray template is to profile their expression patterns by using cross-species hybridization (CSH). Several different studies using spotted microarray for CSH resulted with contradicting conclusions as to the ability of CSH to reflect biological processes. Results: We used a tomato spotted cDNA microarray to examine the ability of CSH to reflect species specific hybridization (SSH) data. Potato RNA was hybridized to spotted cDNA tomato and potato microarrays to generate heterologous and homologous hybridization data, respectively. The results revealed difficulties in obtaining transcriptomics data from CSH that reflected those obtained from SSH. Nevertheless, once the data was filtered for those corresponding to matching probe sets, by restricting proper cutoffs of probe homology, the CSH transcriptomics data better reflected those of the SSH, to an extent that was quantitated by identification of differentially regulated genes. Conclusions: This study enabled us to outline some considerations regarding evaluation of a microarray as candidate platform for CSH study, performance of CSH and proper data analysis that may allow CSH to reflect to some extent a biological process. Keywords: cross-species hybridization; heterologous hybridization
Project description:Significant qualitative and quantitative differences exist between humans and the animal models used in research. However, significant quantitative and qualitative differences exist between humans and the animal models used in research. This is as a result of genetic variation between human and the laboratory animal. Therefore the development of a system that would allow the assessment of all molecular differences between species after drug exposure would have a significant impact on drug evaluation for toxicity and efficacy. Here we describe a cross-species microarray methodology that identifies and selects orthologous probes after cross-species sequence comparison to develop an orthologous cross-species gene expression analysis tool. The assumptions made by the use of this orthologous gene expression strategy for cross-species extrapolation is that; conserved changes in gene expression equate to conserved pharmacodynamic endpoints. This assumption is supported by the fact that evolution and selection have maintained the structure and function of many biochemical pathways over time, resulting in the conservation of many important processes. We demonstrate this difference using a cross-species methodology by investigating species specific differences of the peroxisome proliferator activator receptor (PPAR) alpha in rat and human.
Project description:Significant qualitative and quantitative differences exist between humans and the animal models used in research. However, significant quantitative and qualitative differences exist between humans and the animal models used in research. This is as a result of genetic variation between human and the laboratory animal. Therefore the development of a system that would allow the assessment of all molecular differences between species after drug exposure would have a significant impact on drug evaluation for toxicity and efficacy. Here we describe a cross-species microarray methodology that identifies and selects orthologous probes after cross-species sequence comparison to develop an orthologous cross-species gene expression analysis tool. The assumptions made by the use of this orthologous gene expression strategy for cross-species extrapolation is that; conserved changes in gene expression equate to conserved pharmacodynamic endpoints. This assumption is supported by the fact that evolution and selection have maintained the structure and function of many biochemical pathways over time, resulting in the conservation of many important processes. We demonstrate this difference using a cross-species methodology by investigating species specific differences of the peroxisome proliferator activator receptor (PPAR) alpha in rat and human.
Project description:The determinants of the genetic complexity of Glioblastoma are poorly understood. We generated murine Glioblastomas by transforming glial progenitors in the adult brain with PDGF expression and PTEN deletion +/- p53 deletion. PDGF+PTEN-/- tumors developed additional deletions of specific genes in up to 100% of the tumors, whereas PDGF+PTEN-/-p53-/- tumors did not. Cross-species comparison with data from tCGA database and published in Verhaak, 2010, showed that consistent genetic deletions observed in mouse tumors were specific to human Proneural Glioblastoma. These findings show that the genetic alterations that accumulate during tumor progression are determined by the initiating genetic alterations and by the cellular context in which they occur. Murine gliomas were induced in vivo by retroviral mediated PDGF overexpression, PTEN deletion with or without p53 deletion using Cre/lox system. Tumors were subsequently harvested for sequencing and aCGH analysis. Paired liver DNA was used for hybridization. For PDGF+PTEN-/- tumors, different timepoints were obtained including 21, 35 days post tumor induction, as well as endstage tumors.
Project description:AB SOLID sequencing of ribosome-depleted RNA from S. Cerevisiae, S. Paradoxus, S. Mikatae, and S. Bayanus These four yeast species were grown in complete media and total RNA was sequenced. Cross-Species Gene Expression using RNA-Seq Data was examined. Eight samples examined: two biological replicates of each species