ABSTRACT: This series represents the liver transcriptome for animals sampled during summer, interbout arousal, and late torpor Keywords = squirrel Keywords = liver Keywords = hibernation
Project description:This series represents the heart transcriptome for animals sampled during summer, interbout arousal, and late torpor Keywords = squirrel, heart, hibernation
Project description:This series represents the brain transcriptome for animals sampled during summer, interbout arousal, and late torpor. Note that the brain expression data for interbout aroused animals was not analyzed in our publication because the group consisted of just 2 animals. Keywords = squirrel, brain, hibernation
Project description:This series represents the liver transcriptome for animals sampled during summer, interbout arousal, and late torpor Keywords = squirrel, liver, hibernation
Project description:This series represents the liver transcriptome for animals sampled during summer, interbout arousal, and late torpor Keywords = squirrel Keywords = liver Keywords = hibernation Keywords: other
Project description:This series represents the heart transcriptome for animals sampled during summer, interbout arousal, and late torpor Keywords = squirrel, heart, hibernation Keywords: other
Project description:This series represents the brain transcriptome for animals sampled during summer, interbout arousal, and late torpor. Note that the brain expression data for interbout aroused animals was not analyzed in our publication because the group consisted of just 2 animals. Keywords = squirrel, brain, hibernation Keywords: other
Project description:Mammalian hibernation is a dramatic physiological transition that involves the controlled reduction of regulated body temperature and the consequent depression of all physiological processes. The resulting reduction of metabolism and associated energy expenditure permits survival during extended periods of poor food availability in winter. To date our understanding of the molecular events that give rise to the hibernating phenotype is fragmentary and incomplete. Here, we present a large-scale gene expression screen to explore the transcriptional changes that are associated with the torpid phenotype of the hibernating golden-mantled ground squirrel, Spermophilus lateralis. Expression profiles for liver, cardiac tissue, and brain isolated from summer active, torpid, and interbout aroused animals were generated by hybridization to a squirrel microarray composed of >12,000 cDNA probes. We reveal that the transcriptional changes associated with torpor are modest and generally involve less than 2-fold changes in mRNA level. By profiling the distribution of gene ontological terms in the lists of differentially expressed genes we were able to identify the functional themes that distinguish the summer awake and hibernating phenotypes. In all tissues, the pattern of differential gene expression is consistent with a switch to lipid metabolism during hibernation. In liver, we detected an expression signature suggestive of a profound depression in urea metabolism and detoxification pathways. This expression signature was reproduced in transcript data collected from liver of the13-lined ground squirrel, S. tridecemlineatus, suggesting that this phenotype is conserved between closely related species. The transcriptional changes in cardiac tissue were interpreted as a component of the bradycardia associated with torpor. The function of the differentially expressed transcripts in brain is less transparent, likely due to heterogeneity among the responses of different cell populations in this complex organ.
Project description:This series represents the liver transcriptome for animals sampled during summer, interbout arousal, and late torpor Keywords = squirrel, liver, hibernation Keywords: other
Project description:HMF3A cells, created from adult human mammary fibroblasts by immortalisation with a thermolabile SV40 large T antigen and the catalytic sub-unit of human telomerase, undergo co-ordinated induction of cellular senescence upon inactivation of T antigen. The pSUPER-retro vector system (Brummelkamp, 2002) was used to selectively target genes for mRNA degradation in an attempt to determine if they had a role, in the changes to the transcriptome upon LT inactivation. The genes chosen for targeting were BTG2, NR4A3, DUSP1, PHLDA1 and STACb. Keywords = LT antigen Keywords = senescence Keywords = fibroblast Keywords = BTG2 Keywords = DUSP1 Keywords = MKP-1 Keywords = NR4A3 Keywords = STAC Keywords = PHLDA1 Keywords = RNAi
Project description:HMF3A cells, created from adult human mammary fibroblasts by immortalisation with a thermolabile SV40 large T antigen and the catalytic sub-unit of human telomerase, undergo co-ordinated induction of cellular senescence upon inactivation of T antigen. HMF3A cells cease proliferating by 4 days at 39°C. We directly compared the gene expression profiles of cells at 33.5°C and after shift up to 39.5°C for 7 days (10 arrays, 3 biological replicates). To eliminate genes that change in response to the temperature shift, we compared the profiles of HMF3Dwt cells at 33°C and those shifted up to 39°C for 7 days (4 arrays, 2 biological replicates). Since HMF3Dwt cells were immortalised with wild type U19 LT antigen, they proliferate at both temperatures. To break up the list of genes obtained with the 7 day shift, we performed several further comparisons on the arrays. HMF3A cells at 33°C were compared to the primary donor fibroblasts (HMF3 passage 8, 4 arrays), HMF3A cells shifted to 39°C for 2 days (4 arrays, 2 biological repeats), HMF3A cells shifted to 39°C for 7 days and then shifted back to 33°C for 3 days (8 arrays, 4 biological repeats) or 7 days (4 arrays, 2 biological repeats). As a comparison to the irreversible process of senescence, we sought to identify genes that changed upon reversible growth arrest, quiescence. Thus changes that occurred when the cells were grown to confluency and starved were also determined (2 biological replicate, 6 arrays). Keywords = Rb Keywords = fibroblast Keywords = immortalization Keywords = LT antigen Keywords = p53 Keywords = quiescence Keywords = senescence