Project description:Sex-differences in human liver gene expression were characterized on a genome-wide scale using a large liver sample collection, allowing for detection of small expression differences with high statistical power. 1,249 sex-biased genes were identified, 70% showing higher expression in females. Chromosomal bias was apparent, with female-biased genes enriched on chrX and male-biased genes enriched on chrY and chr19, where 11 male-biased zinc-finger KRAB-repressor domain genes are distributed in six clusters. Top biological functions and diseases significantly enriched in sex-biased genes include transcription, chromatin organization and modification, sexual reproduction, lipid metabolism and cardiovascular disease. Notably, sex-biased genes are enriched at loci associated with polygenic dyslipidemia and coronary artery disease in genome-wide association studies. Moreover, of the 8 sex-biased genes at these loci, 4 have been directly linked to monogenic disorders of lipid metabolism and show an expression profile in females (elevated expression of ABCA1, APOA5 and LDLR; reduced expression of LIPC) that is consistent with the lower female risk of coronary artery disease. Female-biased expression was also observed for CYP7A1, which is activated by drugs used to treat hypercholesterolemia. Several sex-biased drug-metabolizing enzyme genes were identified, including members of the CYP, UGT, GPX and ALDH families. Half of 879 mouse orthologs, including many genes of lipid metabolism and homeostasis, show growth hormone-regulated sex-biased expression in mouse liver, suggesting growth hormone might play a similar regulatory role in human liver. Finally, the evolutionary rate of protein-coding regions for human-mouse orthologs, revealed by dN/dS ratio, is significantly higher for genes showing the same sex-bias in both species than for non-sex-biased genes. These findings establish that human hepatic sex differences are widespread and affect diverse cell metabolic processes, and may help explain sex differences in lipid profiles associated with sex differential risk of coronary artery disease. A first set of randomized liver RNA pools (WS9) was generated by randomly distributing 112 male and 112 female liver RNA samples into 8 pools comprised of 14 male liver samples (pools M1 to M8), and 8 pools of 14 female liver samples each (pools F1 to F8). A second set of 16 pools (WS10) was prepared from the same set of 224 liver samples in the same way (pools M9 to M16 and F9 to F16). The 16 liver RNA pools of each sex were used in a total of 16 male vs. female two-color hybridization microarrays by pairing pool M1 and pool F1, pool M2 with pool F2, etc. Fluorescent labeling of RNA and hybridization of the Alexa 555-labeled and Alexa 647-labeled amplified RNA samples to Agilent Whole Human Genome oligonucleotide microarrays (4 x 44K format; Agilent Technology, Palo Alto, CA; catalog # G4112F) were carried out, with dye swaps to eliminate dye bias.

Project description:The potential for xenoestrogens and other environmental chemicals to alter female reproductive function calls for the study of their affects on endogenous hormone-regulated gene expression pathways during uterine tissue remodeling which occurs as part of the menstrual/estrus cycle. However, our knowledge of these pathways is limited. Here, we characterize changes in the CD-1 mouse uterine transcriptome during proestrus and estrus, which are regulated by estrogen and progesterone in preparation of the uterus for pregnancy. Mice were staged beginning at 6 wk of age and uterine horns were harvested after monitoring two estrus cycles. Microarray analysis identified 2,429 genes differentially expressed in estrus compared to proestrus, indicating that the mouse uterus undergoes remarkable remodeling during the estrus cycle, affecting ~10% of all protein-coding genes. Changes in gene expression associated with structural alteration of the uterus include remodeling of the extracellular matrix, changes in cell keratins and adhesion molecules, activation of mitosis, MHC class II presentation, complement and coagulation cascades, and cytochrome P450 expression. Signaling pathways regulated during the estrus cycle, involving ligand-gated channels, Wnt and hedgehog signaling, and several transcription factors with poorly understood roles in reproductive tissues, include several genes and gene networks that have been implicated in pathological states. The information presented here builds a background for understanding of mechanisms involved in uterine tissue response to endocrine disruptors and the development of reproductive tract diseases. Beginning on postnatal day 42, female CD-1 mice were monitored for reproductive stage cycle for 2 consecutive cycles and then total RNA was isolated from uterine horns at estrus or proestrus. Samples were pooled for microarray as follows. Six litters were used to generate 2 tissue pools for estrus and 2 tissue pools for proestrus, with estrus pool 1 and proestrus pool 1 comprised of mice from the same 3 litters, and estrus pool 2 and proestrus pool 2 comprised of mice from the other 3 litters. Each pool was comprised of uterine tissue RNA from n= 4-6 individual mice. Fluorescent labeling of RNA and hybridization of the Alexa 555-labeled (green) and Alexa 647-labeled (red) RNA samples to Agilent-026655 Whole Mouse Genome Microarray 4x44K v2 (Agilent Technology, Palo Alto, CA; catalog # G4846A) were carried out, with dye swapping for each estrus cycle stage comparison.

Project description:A series of two color gene expression profiles obtained using Agilent 44K expression microarrays was used to examine sex-dependent and growth hormone-dependent differences in gene expression in rat liver. This series is comprised of pools of RNA prepared from untreated male and female rat liver, hypophysectomized (‘Hypox’) male and female rat liver, and from livers of Hypox male rats treated with either a single injection of growth hormone and then killed 30, 60, or 90 min later, or from livers of Hypox male rats treated with two growth hormone injections spaced 3 or 4 hr apart and killed 30 min after the second injection. The pools were paired to generate the following 6 direct microarray comparisons: 1) untreated male liver vs. untreated female liver; 2) Hypox male liver vs. untreated male liver; 3) Hypox female liver vs. untreated female liver; 4) Hypox male liver vs. Hypox female liver; 5) Hypox male liver + 1 growth hormone injection vs. Hypox male liver; and 6) Hypox male liver + 2 growth hormone injections vs. Hypox male liver. A comparison of untreated male liver and untreated female liver liver gene expression profiles showed that of the genes that showed significant expression differences in at least one of the 6 data sets, 25% were sex-specific. Moreover, sex specificity was lost for 88% of the male-specific genes and 94% of the female-specific genes following hypophysectomy. 25-31% of the sex-specific genes whose expression is altered by hypophysectomy responded to short-term growth hormone treatment in hypox male liver. 18-19% of the sex-specific genes whose expression decreased following hypophysectomy were up-regulated after either one or two growth hormone injections. Finally, growth hormone suppressed 24-36% of the sex-specific genes whose expression was up-regulated following hypophysectomy, indicating that growth hormone acts via both positive and negative regulatory mechanisms to establish and maintain the sex specificity of liver gene expression. For full details, see V. Wauthier and D.J. Waxman, Molecular Endocrinology (2008) This series is comprised of pools of liver RNA prepared from untreated male, hypophysectomized (‘Hypox’) male, untreated female and Hypox female rats (3-4 livers/pool), as well as liver RNA prepared from Hypox male rats treated with a single growth hormone injection and killed either 30, 60, or 90 minutes later (pool of n = 4 livers) or from Hypox male rats treated with two growth hormone injections spaced 3 or 4 hr apart (pool of n = 5 livers). The pools were paired to generate the following 6 direct microarray comparisons: 1) untreated male liver vs. untreated female liver; 2) Hypox male liver vs. untreated male liver; 3) Hypox female liver vs. untreated female liver; 4) Hypox male liver vs. Hypox female liver; 5) Hypox male liver + 1 growth hormone injection vs. Hypox male liver; and 6) Hypox male liver + 2 growth hormone injections vs. Hypox male liver. Dye swapping experiments were carried out for each of the six hybridization experiments, as follows. The Alexa 555-labeled cDNA from one of the two untreated male pools was mixed with the Alexa 647-labeled cDNA from one of the two untreated female pools. Similarly, Alexa 647-labeled cDNA from the second untreated male pool was mixed with the Alexa 555-labeled cDNA from the second untreated female pool. Together, these two mixed cDNA samples comprise a fluorescent reverse pair (dye swap). Dye swaps were similarly carried out for each of the five other competitive hybridization experiments, except that for experiments 5 and 6, a single pool of M-Hypox + GH liver cDNA, or a single pool of M-Hypox + 2GH liver cDNA, was used in each half of the fluorescent reverse pair. Two microarrays, one for each mixed cDNA sample, were hybridized for each of the six fluorescent reverse pairs, giving a total of 12 microarrays.

Project description:This study was designed to identify changes in gene expression that occur when corn was grown on different landscape features. Specifically on the backslope or summit/shoulder of a hill. In rolling landscapes, plant available water varies drastically by location and soil type. Almost simultaneously, plants may be flooded out in footslope locations whereas plants in summit locations may be suffering from severe drought. The objective of this study was to determine the influence of landscape position on corn (Zea mays) productivity and gene regulation. Corn was sampled at V12 for plant growth characteristics and transcriptome analysis at summit/shoulder and lower backslope positions. Plants at the summit had 16% less leaf area and biomass compared with plants at the toeslope. Gene expression analysis using microarray chips, transcriptome analysis, and qPCR indicated that plants at the summit had 708 genes down-regulated and 399 genes up-regulated compared to control plants at the lower back slope. GSEA (Gene Set Enrichment Analysis) indicated tolerance to cold, salt, and drying were increased in summit/should plants compared to control toeslope plants. However, nutrient uptake, recovery from wounding, pest and fungal disease resistance, along with photosynthetic capacity were all down-regulated in moderate water stresses plants. These responses suggest that corn preferentially responses to water stress as the expense of its ability to respond to other stresses. Three biological replicates for the control (backslope) and six biological replicate of summit/shoulder-grown plants were collected. The resulting labeled cDNA was hybridized to the 46,000-element maize microarray chip developed by the University of Arizona using their protocol (International Microarray Workshop Handbook, 2009Gardiner et al. 2005). The hybridization scheme was a dual hybridization using a rolling circle balanced dye swap design. Thus we had three to six biological replicates for each growth condition and two technical replicates for each biological sample.

Project description:BACKGROUND: Cancer stem-like cells were isolated from human H460 non-small cell lung cancer cells by limiting dilution assays and by their holoclone morphology, followed by assessment of their self-renewal capacity, tumor growth, vascularity, and tumor blood perfusion. H460 holoclones were used to implant H460 holoclone-derived tumors, which grew slower than parental H460 tumors, but displayed significant increases in microvessel density and tumor blood perfusion. Microarray analysis identified differentially regulated genes in the holoclone-derived tumors, of which many were associated with angiogenesis. The differentially regulated genes include several small leucine-rich proteoglycans that may modulate angiogenesis and serve as novel therapeutic targets for inhibiting cancer stem cell-driven angiogenesis.(Cancer Letters Vol 346, Issue 1, 28 April 2014, Pages 63M-bM-^@M-^S73; PMID: 24334139; PMCID: PMC3947657). Implanted tumors derived from H460 parental cells, or from each of four independent H460 holoclones, were implanted subcutaneously in scid immunodeficient mice. Tumors derived from the 4 holoclones (designated H460/2E1, H460/2H3, H460/3F1, and H460/2E7) were used for global transcriptome/microarray analysis in direct comparison to H460 tumors grown from parental H460 cells. For each H460 holoclone-derived tumor line or H460 parental cell-derived tumor, total RNA was prepared from n=7 to n=10 individual tumors and used to prepare two independent pools of tumor RNA (each pool comprised of RNA isolated n=3-5 tumors) for use in a two color microarray analysis. Tumor RNA pools were prepared by combining equal amounts of RNA from each individual tumor to minimize the impasct of inter-tumoral variation on gene expression profiles. All RNAs had an RNA integrity number >8.0, determined using an Agilent Bioanalyzer 2100 instrument. cDNAs transcribed from pools of RNA for each holoclone-derived tumor line and for each parental H460 cell-derived tumor pool, were labeled with Alexa 647 or Alexa 555 dyes in a fluorescent reverse pair (dye swap) design for competitive hybridization to Agilent Whole Human Genome Microarrays.

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Using Shewanella baltica ecotypes as a model for transcriptional variation

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