Because refractive development is governed largely by the retina, we analyzed the retinal transcriptome in chicks wearing a spectacle lens, a well-established means to induce refractive errors, to identify gene expression alterations and to develop novel mechanistic hypotheses about refractive development.
Image defocus and altered retinal gene expression in chick: clues to the pathogenesis of ametropia.
Specimen part
View SamplesTo gain insight into the dynamic molecular processes that are altered during prolonged wakefulness and during sleep. We performed an RNA expression profiling study examining temporal changes in the brain of Drosophila in relationship to the duration of prior sleep or wakefulness. Our experimental design allowed us to determine whether genes identified as differentially regulated between sleep and wakefulness were up- or down-regulated in these states.
Multiple mechanisms limit the duration of wakefulness in Drosophila brain.
Sex, Age, Specimen part
View SamplesPeripheral circadian clocks regulate many aspects of physiology. In this study we deleted the core circadian clock component Bmal1 specifically in mouse adipocytes in order to study the role of the adipocyte clock in energy homeostasis and body weight. We used microarrays to indentify changes in gene expression in the adipose tissue of mice lacking a functional adipocyte circadian clock and identified a small number of up- and down- regulated genes.
Obesity in mice with adipocyte-specific deletion of clock component Arntl.
Specimen part
View SamplesOne-day old white Leghorn chicks were housed in brooders with a 12 hr light:dark cycle, using General Electric chroma 50 fluorescent lighting with irradiance of approximately 50W/cm2 at chick eye level. They received Purina Chick Chow food and water ad libitum. At one week of age and at the onset of the light phase, the chicks were anesthetized with inhalation ether, and a unilateral translucent white plastic goggle was glued to the periorbital feathers to induce ipsilateral form-deprivation myopia, alternating between the left or right eye.
Form-deprivation myopia in chick induces limited changes in retinal gene expression.
No sample metadata fields
View SamplesWe treated logarithmically growing cultures of E.coli with a sub-lethal dose of an antimicrobial arylamide compound (PMX 10070) and Polymyxin B sulfate to measure transcriptional responses in an effort to understand mechanism of action
Antibacterial mechanism of action of arylamide foldamers.
No sample metadata fields
View SamplesAnalysis of heart ventricles from Hopx, Hdac2, and both Hopx-Hdac2 deficient embryos at embryonic day E16.5. Results provide insight into the role of Hopx and Hdac2 in cardiac development.
No associated publication
Specimen part
View SamplesThe goal was to identify genes targeted by miR-30a.
The microRNA-30 family is required for vertebrate hepatobiliary development.
No sample metadata fields
View SamplesBackground & Aims: MiRNAs are small (~22 nucleotide), non-coding RNA molecules that regulate gene expression through imperfect complementarity with target messenger RNAs. The function of miRNA in mammalian organogenesis is largely unknown. Conditional loss-of-function of Dicer, the enzyme that processes precursor miRNA transcripts into their mature, active form, has been shown to cause severe defects in a number of organ systems. Here we address the role of Dicer in liver development and function. Methods: Mice lacking Dicer function in hepatocytes were generated using an Afp-Cre strain to drive deletion of a floxed Dicer allele. Deletion of the flox-dicer allele was confirmed by quantitative PCR. Decreased miRNA levels detected by quantitative RT-PCR and in situ hybridization confirmed loss of Dicer function. Gene expression microarray analysis was performed on liver RNA from P28 mutant and control mice. Liver sections from mutant and control mice ranging from embryonic stages through 3-4 months of age were examined and liver function tests were performed on adult mice. Results: Mice lacking hepatocyte Dicer function were born alive at the expected frequency, and had grossly normal appearance and behavior. Despite the loss of mature miRNA, hepatic function was normal, as reflected by normal blood gludose, albumin, cholesterol, and bilirubin. However, mutant mice between 2-4 months of age exhibit progressive hepatocyte damage, elevated ALT/AST, with evidence of balanced proliferation and apoptosis in the lobule. Microarray analysis indicates large-scale changes in gene expression, with increased expression of many miRNA targets, as well as imprinted genes. Conclusions: Loss of miRNA processing in the liver at late gestation has a remarkably mild phenotype, suggesting that miRNAs do not play an essential role in hepatic physiology. However, miRNA deficiency results in hepatocyte apoptosis and balanced hepatocyte regeneration. Finally, microarray analysis of gene expression in mutant liver suggests a previously unrecognized role for Dicer in the repression of imprinted genes.
Hepatic function is preserved in the absence of mature microRNAs.
Age, Specimen part
View SamplesAdult BALB/c female mice were injected intraperitoneally with a single dose at 20 mg per kg of antisense oligonucleotide either against miR-29a (5-TAACCGATTTCAGATGGTGCTA-3) or against a scrambled sequence (5-TCATTGGCATGTACCATGCAGCT-3 Antisense oligonucleotides contained 2-O-methoxyethyl (2-MOE), 2-flouro (2-F) 2'-alpha-flouro units with a phosphorothioate backbone (Regulus Therapeutics). Six days following the injection, liver was isolated, total RNA was prepared as described above, and the RNA was amplified and biotinylated using the MessageAmp Premier kit (Ambion). Samples (n=4 each experimental and control) were hybridized to Affymetrix GeneChip Mouse Genome 430 2.0 Arrays in the Childrens Hospital of Philadelphia Nucleic Acids Core Facilityand analyzed with the assistance of the Penn Bioinformatics Core. Probe intensities were normalized using the GCRMA method and the significance of the log2-transformed, GCRMA-normalized signal intensities was determined using SAM
MicroRNA profiling identifies miR-29 as a regulator of disease-associated pathways in experimental biliary atresia.
Sex, Specimen part, Treatment
View SamplesIntrauterine growth restriction is a common complication of pregnancy. We induce IUGR in rats by bilateral uterine artery ligation at e18 of a 23 day gestation.
Neutralizing Th2 inflammation in neonatal islets prevents β-cell failure in adult IUGR rats.
Specimen part, Treatment
View Samples