The contrasting dose of sex chromosomes in males and females potentially introduces a large-scale imbalance in levels of gene expression between sexes. In many organisms dosage compensation has thus evolved to equalize sex-linked gene expression in males and females1,2, in mammals achieved by X chromosome inactivation and in flies and worms by up- or down-regulation of X-linked expression, respectively. Another form of dosage compensation ensures that expression levels on the X chromosome and on autosomes are balanced3,4. While otherwise widespread in systems with heteromorphic sex chromosomes, the case of dosage compensation in birds (males ZZ, females ZW) remains an unsolved enigma5,6. Here we use a microarray approach to show that male day 18 chicken embryos generally express higher levels of Z-linked genes than female birds, both in soma and in gonads. The distribution of male-to-female fold-change values for Z chromosome genes is wide and has a mean of 1.4-1.6, which is consistent with absence of dosage compensation and sex-specific feedback regulation of gene expression at individual loci2. Intriguingly, without global dosage compensation, female chicken has significantly lower expression levels of Z-linked compared to autosomal genes, which is not the case in male birds. The pronounced sex difference in gene expression is likely to contribute to sexual dimorphism among birds, and potentially has implication to avian sex determination.
Faced with inequality: chicken do not have a general dosage compensation of sex-linked genes.
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View SamplesBackground: Obesity is a risk factor for breast cancer in postmenopausal women and is associated with decreased survival and less favorable clinical characteristics such as greater tumor burden, higher grade, and poor prognosis, regardless of menopausal status. Despite the negative impact of obesity on clinical outcome, molecular mechanisms through which excess adiposity influences breast cancer etiology are not well-defined.
Effect of obesity on molecular characteristics of invasive breast tumors: gene expression analysis in a large cohort of female patients.
Disease stage
View SamplesPurpose: identifying genes responding to insulin stimulation in S2R+ cells through whole transcriptome RNA-seq analyses Methods: Total RNA was extracted from S2R+ cells using TRIzol® reagent (Invitrogen). After assessing RNA quality with an Agilent Bioanalyzer, libraries were constructed with Illumina TruSeq mRNA Library Prep Kit , libraries were sequenced using an Illumina HiSeq 4000 at the Columbia Genome Center (http://systemsbiology.columbia.edu/genome-center). Results: Using an time series data analysis workflow incorporating polynormials , we identified 1254 temproally differentially expressed genes responding to insulin stimulation in the S2R+ cells. Overall design: the pre-starved S2R+ cells ( with serum free medium) were stimulated with insulin; triplicate samples were collected at basline and every 20minutes time interval up to three hours; transcriptome profiling
Interspecies analysis of MYC targets identifies tRNA synthetases as mediators of growth and survival in MYC-overexpressing cells.
Specimen part, Treatment, Subject, Time
View SamplesUremic media calcification is not only driven by systemic factors such as hyperphosphatemia, but also crticially dependent on vascular smooth muscle cells per se. We hypothesized that the different developmental origins of vscular smooth muscle cells might lead to a heterogeneous susceptibility to develop media calcification.
Heterogeneous susceptibility for uraemic media calcification and concomitant inflammation within the arterial tree.
Specimen part
View SamplesTruncating CHD8 mutations are amongst the highest confidence risk factors for autism spectrum disorders (ASD) identified to date. Here, we report that Chd8 heterozygous mice display increased brain size, motor delay, hypertelorism, pronounced hypoactivity, and anomalous responses to social stimuli. Whereas gene expression in the neocortex is only mildly affected at mid gestation, over 600 genes are differentially expressed in the early postnatal neocortex. Genes involved in cell adhesion and axon guidance are particularly prominent amongst the downregulated transcripts. Resting-state functional MRI identified increased synchronized activity in corticohippocampal and auditory-parietal networks in Chd8 heterozygous mutant mice, implicating altered connectivity as a potential mechanism underlying the behavioral phenotypes. Together, these data suggest that altered brain growth and diminished expression of important neurodevelopmental genes that regulate long-range brain wiring are followed by distinctive anomalies in functional brain connectivity in Chd8 +/- mice. Human imaging studies have reported altered functional connectivity in ASD patients, with long-range under-connectivity seemingly more frequent. Our data suggest that CHD8 haploinsufficiency represents a specific subtype of ASD where neuropsychiatric symptoms are underpinned by long-range over-connectivity. Overall design: RNA was isolated from microdissected cortices at E12.5 (both hemispheres) and P5 (one hemisphere and DNase-treated using the Direct-zol RNA MiniPrep kit (Zymo Research) according to the manufacturer?s instructions (n = 3 per experimental group). cDNA was end-repaired, adaptor-ligated, and A-tailed. Samples were sequenced over 2 lanes of the Illumina HiSEq 4000 platform.
Altered Neocortical Gene Expression, Brain Overgrowth and Functional Over-Connectivity in Chd8 Haploinsufficient Mice.
Specimen part, Subject
View SamplesPurpose: Aerobic capacity is a strong predictor of cardiovascular mortality. To determine the relationship between inborn aerobic capacity and soleus gene expression we examined genome-wide gene expression in soleus muscle of rats artificially selected for high and low running capacity (HCR and LCR, respectively) over 16 generations. The artificial selection of LCR caused accumulation of risk factors of cardiovascular disease similar to the metabolic syndrome seen in man, whereas HCR had markedly better cardiac function. We also studied alterations in gene expression in response to exercise training in the two groups, since accumulating evidence indicates that exercise has profound beneficial effects on the metabolic syndrome.
Gene expression profiling of skeletal muscle in exercise-trained and sedentary rats with inborn high and low VO2max.
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View SamplesAerobic capacity is a strong predictor of cardiovascular mortality. To determine the relationship between aerobic capacity and cardiac gene expression we examined genome-wide gene expression in hearts of rats artificially selected for high- and low running capacity (HCR and LCR, respectively) over 16 generations. HCR were born with an athletic phenotype, whereas LCR exhibited features of the metabolic syndrome.
Aerobic capacity-dependent differences in cardiac gene expression.
Sex
View SamplesThese patients proved resistant to docetaxel treatment, exhibiting residual tumor of 25% or greater remaining volume.
Gene expression profiling for the prediction of therapeutic response to docetaxel in patients with breast cancer.
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View SamplesThese patients were sensitive to docetaxel treatment, exhibiting less than 25% residual tumor.
Gene expression profiling for the prediction of therapeutic response to docetaxel in patients with breast cancer.
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View SamplesEndocrine therapy in patients with breast cancer can be limited by the problem of resistance. Preclinical studies suggest that complete blockade of the estrogen receptor (ER) combined with inhibition of the epidermal growth factor receptor (EGFR) can overcome endocrine resistance. We tested this hypothesis in a phase II neoadjuvant trial of anastrozole and fulvestrant combined with gefitinib in postmenopausal women with newly diagnosed ER-positive breast cancer. After a baseline tumor core biopsy, patients were randomized to receive anastrozole and fulvestrant (AF) or anastrozole, fulvestrant, and gefitinib (AFG) for 3 weeks. After a second biopsy at 3 weeks, all patients received AFG for 4 months and surgery was done if the tumor was operable. The primary endpoint was best clinical response by RECIST criteria and secondary endpoints were toxicity and change in biomarkers. The study closed after 15 patients were enrolled because of slow accrual. Median patient age was 67 years and median clinical tumor size was 7 cm. Four patients had metastatic disease present. Three patients withdrew before response was assessed. In the remaining twelve patients, there were two complete clinical responses (17%), three partial responses (25%), five had stable disease (41%), and two (17%) had progressive disease. Most common adverse events were rash in four patients, diarrhea in four, joint symptoms in three, and abnormal liver function tests in three. There were no grade 4 toxicities and all toxicities were reversible. At 3 weeks, cell proliferation as measured by Ki-67 was significantly reduced in the AFG group (p value= 0.01) with a parallel reduction in the expression of the Cyclin D1 (p value=0.02). RNA microarray data showed a corresponding decrease in the expression of cell cycle genes. These results suggest that AFG was an effective neoadjuvant therapy and consistently reduced proliferation in ER-positive tumors.
A phase II neoadjuvant trial of anastrozole, fulvestrant, and gefitinib in patients with newly diagnosed estrogen receptor positive breast cancer.
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