Global Differential Gene Expression Research Articles

ImmuSort, a database on gene plasticity and electronic sorting for immune cells

Gene expression is highly dynamic and plastic. We present a new immunological database, ImmuSort. Unlike other gene expression databases, ImmuSort provides a convenient way to view global differential gene expression data across thousands of experimental conditions in immune cells. It enables electronic sorting, which is a bioinformatics process to retrieve cell states associated with specific experimental conditions that are mainly based on gene expression intensity. A comparison of gene expression profiles reveals other applications, such as the evaluation of immune cell biomarkers and cell subsets, identification of cell specific and/or disease-associated genes or transcripts, comparison of gene expression in different transcript variants and probe set quality evaluation. A plasticity score is introduced to measure gene plasticity. Average rank and marker evaluation scores are used to evaluate biomarkers. The current version includes 31 human and 17 mouse immune cell groups, comprising 10,422 and 3,929 microarrays derived from public databases, respectively. A total of 20,283 human and 20,963 mouse genes are available to query in the database. Examples show the distinct advantages of the database. The database URL is http://202.85.212.211/Account/ImmuSort.html.

Progressive differentiation of follicular B helper T cells regulates the germinal center response (IRC11P.430)

Abstract Initiation of a thymus-dependent humoral immune response requires interaction of activated B cells and follicular B helper T (Tfh) cells, a specialized subset of CD4 T cells. Differentiation of Tfh cells results in their localization to the B-cell follicle and germinal center (GC) of secondary lymphoid organs and expression of the transcription factor Bcl6. Here we show Tfh cells differentiate further within the follicle and GC, with development of discrete subsets that regulate distinct aspects of B-cell maturation. Using mice expressing reporter genes for IL-21 and IL-4, we found that Tfh cells initially produce IL-21 mRNA and protein and support selection of high-affinity B cell mutations. Gradually, Tfh cells began to produce IL-4 and while ceasing production of IL-21, and demonstrated the ability to induce class-switch recombination and development of antibody-secreting cells. These changes in phenotype and function occurred as these Tfh21- and Tfh4-subsets exhibited differences in global gene expression as well as localization within the GC. These data support a model in which ongoing Tfh-cell differentiation orchestrates the formation of an effective antibody response.

Transcriptional responses of tolerant and susceptible soybeans to soybean aphid (Aphis glycines Matsumura) herbivory

The soybean aphid, Aphis glycines Matsumura, was introduced in 2000 to North America and has become one of the most significant pests to soybean, Glycine max (L.) Merrill, production. Possible solutions to this problem are the use of resistant plants and the understanding of the genes involved in plant resistance. In this study, we sought to better understand the genes involved in the tolerance response of soybean plants to the soybean aphid, utilizing tolerant (KS4202) and susceptible (K-03-4686) plants. Studies were conducted under greenhouse conditions. Leaf samples of both tolerant and susceptible plants were collected at day 5 and day 15 after infestation and analyzed by sequencing-by-synthesis on an Illumina GA II X instrument. In the tolerant genotype, 3 and 36 genes were found to be differentially expressed in the infested plants compared to the control treatments at day 5 and day 15, respectively. A similar comparison in the susceptible genotype revealed 0 and 11 genes to be differentially expressed at day 5 and day 15, respectively. Predominately, genes related to plant defense, such as WRKY transcription factors, peroxidases, and cytochrome p450s, were up-regulated in the tolerant genotype 15 days post-infestation by aphids. In contrast, none of these genes were similarly up-regulated in the susceptible plants, suggesting that consistent elevation of defense responses is important to plant tolerance. However, significant genotypic differences in global gene expression were also found when transcriptomes from control uninfested plants were compared at both day 5 and 15. qPCR validation of select genes confirmed our RNA-seq data. These comparisons indicate that potentially broader regulation of transcriptomes also contributes to the tolerance response and provides data that the tolerant genotype (KS4202) could be useful in soybean breeding programs trying to minimize production losses accruing from soybean aphid feeding.

Global liver gene expression differences in Nelore steers with divergent residual feed intake phenotypes.

BackgroundEfficiency of feed utilization is important for animal production because it can reduce greenhouse gas emissions and improve industry profitability. However, the genetic basis of feed utilization in livestock remains poorly understood. Recent developments in molecular genetics, such as platforms for genome-wide genotyping and sequencing, provide an opportunity to identify genes and pathways that influence production traits. It is known that transcriptional networks influence feed efficiency-related traits such as growth and energy balance. This study sought to identify differentially expressed genes in animals genetically divergent for Residual Feed Intake (RFI), using RNA sequencing methodology (RNA-seq) to obtain information from genome-wide expression profiles in the liver tissues of Nelore cattle.ResultsDifferential gene expression analysis between high Residual Feed Intake (HRFI, inefficient) and low Residual Feed Intake (LRFI, efficient) groups was performed to provide insights into the molecular mechanisms that underlie feed efficiency-related traits in beef cattle. A total of 112 annotated genes were identified as being differentially expressed between animals with divergent RFI phenotypes. These genes are involved in ion transport and metal ion binding; act as membrane or transmembrane proteins; and belong to gene clusters that are likely related to the transport and catalysis of molecules through the cell membrane and essential mechanisms of nutrient absorption. Genes with functions in cellular signaling, growth and proliferation, cell death and survival were also differentially expressed. Among the over-represented pathways were drug or xenobiotic metabolism, complement and coagulation cascades, NRF2-mediated oxidative stress, melatonin degradation and glutathione metabolism.ConclusionsOur data provide new insights and perspectives on the genetic basis of feed efficiency in cattle. Some previously identified mechanisms were supported and new pathways controlling feed efficiency in Nelore cattle were discovered. We potentially identified genes and pathways that play key roles in hepatic metabolic adaptations to oxidative stress such as those involved in antioxidant mechanisms. These results improve our understanding of the metabolic mechanisms underlying feed efficiency in beef cattle and will help develop strategies for selection towards the desired phenotype.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1464-x) contains supplementary material, which is available to authorized users.

Cytoplasmic accumulation of NCoR in malignant melanoma: consequences of altered gene repression and prognostic significance.

Invasive malignant melanoma (MM) is an aggressive tumor with no curative therapy available in advanced stages. Nuclear corepressor (NCoR) is an essential regulator of gene transcription, and its function has been found deregulated in different types of cancer. In colorectal cancer cells, loss of nuclear NCoR is induced by Inhibitor of kappa B kinase (IKK) through the phosphorylation of specific serine residues. We here investigate whether NCoR function impacts in MM, which might have important diagnostic and prognostic significance. By IHC, we here determined the subcellular distribution of NCoR in a cohort of 63 primary invasive MM samples, and analyzed its possible correlation with specific clinical parameters. We therefore used a microarray-based strategy to determine global gene expression differences in samples with similar tumor stage, which differ in the presence of cytoplasmic or nuclear NCoR. We found that loss of nuclear NCoR results in upregulation of a specific cancer-related genetic signature, and is significantly associated with MM progression. Inhibition of IKK activity in melanoma cells reverts NCoR nuclear distribution and specific NCoR-regulated gene transcription. Analysis of public database demonstrated that inactivating NCoR mutations are highly prevalent in MM, showing features of driver oncogene.

Transcriptomic analysis to elucidate the molecular mechanisms that underlie feed efficiency in meat-type chickens.

Feed efficiency phenotypes defined by genotypes or gene markers are unknown. To date, there are only limited studies on global gene expression profiling on feed efficiency. The objective of this study was to identify genes and pathways associated with residual feed intake (RFI) through transcriptional profiling of duodenum at two different ages in a chicken population divergently selected for low (LRFI) or high (HRFI) RFI. The global gene expression differences in LRFI and HRFI were assessed by the Affymetrix GeneChip(®) Chicken Genome Array and RT-PCR using duodenal tissue on days 35 and 42. The Ingenuity Pathway Analysis program was used to identify canonical and gene network pathways associated with RFI. A global view of gene expression differences between LRFI and HRFI suggest that RFI can be explained by differences in cell division, growth, proliferation and apoptosis, protein synthesis, lipid metabolism, and molecular transport of cellular molecules. Chickens selected for improved RFI achieve efficiency by reducing feed intake with a nominal or no change in weight gain by either up-regulating CD36, PPARα, HMGCS2, GCG or down-regulating PCSK2, CALB1, SAT1, and SGK1 genes within the lipid metabolism, small molecule biochemistry, molecular transport, cell death, and protein synthesis molecular and cellular functions. Chickens selected for reduced RFI via reduced feed intake with no change in weight gain achieve feed efficiency for growth by the up-regulation of genes that reduce appetite with increased cellular oxidative stress, prolonged cell cycle, DNA damage, and apoptosis in addition to increased oxidation of dietary fat and efficient fatty acids transported from the intestines.

Altered monocyte expression and expansion of non-classical monocyte subset in IgA nephropathy patients

The main defect of immunoglobulin A nephropathy (IgAN) lies within the immune system and in peripheral blood mononuclear cells rather than in the kidney. Previously, we found an altered gene expression in monocytes compared with B and T cells isolated from IgAN patients; thus, our aim here has been to study this subset at a genome-wide and functional level. A total of 39 IgAN patients and 37 healthy blood donors (HBDs) were included in this study, and microarray technology was used to evaluate global gene expression differences in monocytes isolated from IgAN patients and HBDs. Aberrantly expressed genes and pathways were then validated on an independent set of IgAN patients with RT-PCR western blot and flow cytometric analysis. Gene expression differences in monocytes from IgAN patients and HBDs primarily involved apoptosis signalling, mitochondrial dysfunction, tnfr2/1 and death receptor signalling. Both the extrinsic and intrinsic apoptotic pathways seem to be implicated; in particular, the protein levels of NDUFS3 and TNFRSF1A were upregulated thus confirming the altered mitochondrial and death receptor homeostasis. Furthermore, the basal intracellular protein levels of TNF in monocytes were lower in IgAN patients compared with HBDs. We validated at protein level an enhanced apoptotic phenotype and a different subset distribution in monocytes from IgAN patients. We found that the non-classical monocyte subset (CD14(+)CD16(+)) was significantly expanded in all IgAN patients tested even though the total monocyte count remained unchanged. Our findings demonstrate, for the first time, an aberrant modulation of the mitochondrial respiratory system in monocytes isolated from IgAN patients. Furthermore, the aberrant expansion of the (CD14(+)CD16(+)) subset could explain the enhanced apoptotic phenotype seen in these cells thus revealing their potential role in the pathogenesis of IgAN.

Transcript profiling of Populus tomentosa genes in normal, tension, and opposite wood by RNA-seq.

BackgroundWood formation affects the chemical and physical properties of wood, and thus affects its utility as a building material or a feedstock for biofuels, pulp and paper. To obtain genome-wide insights on the transcriptome changes and regulatory networks in wood formation, we used high-throughput RNA sequencing to characterize cDNA libraries of mature xylem from tension wood (TW), opposite wood (OW), and normal wood (NW), in the industrial tree species Populus tomentosa.ResultsOur sequencing generated 140,978,316 (TW), 128,972,228 (OW), and 117,672,362 (NW) reads, corresponding to 10,127 (TW), 10,129 (OW), and 10,129 (NW) unique genes. Of these, 361 genes were differentially transcribed between TW and OW (log2FC ≥ 1 or ≤ -1, FDR < 0.05), 2,658 differed between OW and NW, and 2,417 differed between TW and NW. This indicates that NW differs significantly from the wood in branches; GO term analysis also indicated that OW experienced more transcriptome remodeling. The differentially expressed genes included 97 encoding transcription factors (TFs), 40 involved in hormone signal transduction, 33 in lignin biosynthesis, 21 in flavonoid biosynthesis, and 43 in cell wall metabolism, including cellulose synthase, sucrose synthase, and COBRA. More than half of the differentially expressed TF showed more than 4-fold lower transcript levels in NW compared with TW or OW, indicating that TF abundances differed dramatically in different wood types and may have important roles in the formation of reaction wood. In addition, transcripts of most of the genes involved in lignin biosynthesis were more abundant in OW compared with TW, consistent with the higher lignin content of OW. We constructed two transcriptomic networks for the regulation of lignin and cellulose biosynthesis, including TFs, based on the co-expression patterns of different genes. Lastly, we used reverse transcription quantitative PCR to validate the differentially expressed genes identified.ConclusionsHere, we identified the global patterns and differences in gene expression among TW, OW, and NW, and constructed two transcriptomic regulatory networks involved in TW formation in P. tomentosa. We also identified candidate genes for molecular breeding of wood quality, and provided a starting point to decipher the molecular mechanisms of wood formation in Populus.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1390-y) contains supplementary material, which is available to authorized users.

English

Overuse of inorganic fertilizers have contributed to an increase in soil acidity in global arable land and consequently caused an increase in Aluminium ion (Al3+) toxicity and a reduction of crop yield of between 30-50% in developing countries. Studies show that Al3+ toxicity inhibits cell division in the root tip meristem in sensitive plants even at micromolar concentrations. Applications of lime, manure and compost are some of the most common methods used to overcome the impact of Al3+ toxicity. Other studies have identified natural variation for the multigenic Al3+ tolerance trait in many crop species and can be utilized in crop improvement. This review highlights a search for a clearer understanding of the molecular basis for Aluminium ion toxicity by correlating heterosis and epigenetic mechanisms like DNA Cytosine methylation in inbred and reciprocal maize hybrids crosses. Several recent studies indicated that the global differential gene expression regulated by epigenetic mechanisms between hybrids and parental inbred lines can potentially contribute to heterosis in maize. Key words: Maize, heterosis, tolerance, epigenetics, aluminium ion toxicity.

NOB1 is essential for the survival of RKO colorectal cancer cells.

To determine the role of NOB1, a regulator of cell survival in yeast, in human colorectal cancer cells. Lentivirus-mediated small interfering RNA (siRNA) was used to inhibit NOB1 expression in RKO human colorectal cancer cells in vitro and in vivo in a mouse xenograft model. The in vitro and in vivo knockdown efficacy was determined using both Western blot and quantitative reverse transcription polymerase chain reaction (qRT-PCR). qRT-PCR was also used to analyze the downstream signals following NOB1 knockdown. Cell growth and colony formation assays were used to determine the effect of NOB1 inhibition on RKO proliferation and their ability to form colonies. Endonuclease activity, as evaluated by terminal deoxytransferase-mediated dUTP nick end labeling (TUNEL), and annexin V staining were used to determine the presence of apoptotic cell death prior to and following NOB1 inhibition. Cell cycle analysis was used to determine the effect of NOB1 inhibition on RKO cell cycle. A cDNA microarray was used to determine global differential gene expression following NOB1 knockdown. Virus-mediated siRNA inhibition of NOB1 resulted in (1) the down-regulation of NOB1 expression in RKO cells for both the mRNA and protein; (2) inhibition of NOB1 expression both in vitro and in vivo experimental systems; (3) cell growth inhibition via significant induction of cell apoptosis, without alteration of the cell cycle distribution; and (4) a significant decrease in the average weight and volume of xenograft tumors in the NOB1-siRNA group compared to the control scr-siRNA group (P = 0.001, P < 0.05). Significantly more apoptosis was detected within tumors in the NOB1-siRNA group than in the control group. Microarray analysis detected 2336 genes potentially regulated by NOB1. Most of these genes are associated with the WNT, cell proliferation, apoptosis, fibroblast growth factor, and angiogenesis signaling pathways, of which BAX and WNT were validated by qRT-PCR. Among them, 1451 probes, representing 963 unique genes, were upregulated; however, 2308 probes, representing 1373 unique genes, were downregulated. NOB1 gene silencing by lentivirus-mediated RNA interference can inhibit tumor growth by inducing apoptosis of cancerous human colorectal cells.

Transcriptional profiles reveal a stepwise developmental program of memory CD8+ T cell differentiation

The generation of CD8+ T-cell memory is a major aim of vaccination. While distinct subsets of CD8+ T-cells are generated following immunization that differ in their ability to confer long-term immunity against infection, the transcriptional profiles of these subsets within endogenous vaccine-induced CD8+ T cell responses have not been resolved. Here, we measure global transcriptional profiles of endogenous effector (TEFF), effector memory (TEM) and central memory (TCM) CD8+ T-cells arising from immunization with three distinct prime-boost vaccine regimens. While a proportion of transcripts were uniquely regulated within distinct CD8+ T cell populations, we observed progressive up- or down-regulation in the expression of a majority of differentially expressed transcripts when subsets were compared in the order TN>TCM>TEM>TEFF. Strikingly, when we compared global differences in gene expression between TN, TCM, TEM and TEFF cells with known transcriptional changes that result when CD8+ T cells repetitively encounter antigen, our analysis overwhelmingly favored a model whereby cumulative antigen stimulation drives differentiation specifically from TN>TCM>TEM>TEFF and this was common to all vaccines tested. These findings provide insight into the molecular basis of immunological memory and identify potential biomarkers for characterization of vaccine-induced responses and prediction of vaccine efficacy.

Examination of the genetic basis for sexual dimorphism in the Aedes aegypti (dengue vector mosquito) pupal brain.

BackgroundMost animal species exhibit sexually dimorphic behaviors, many of which are linked to reproduction. A number of these behaviors, including blood feeding in female mosquitoes, contribute to the global spread of vector-borne illnesses. However, knowledge concerning the genetic basis of sexually dimorphic traits is limited in any organism, including mosquitoes, especially with respect to differences in the developing nervous system.MethodsCustom microarrays were used to examine global differences in female vs. male gene expression in the developing pupal head of the dengue vector mosquito, Aedes aegypti. The spatial expression patterns of a subset of differentially expressed transcripts were examined in the developing female vs. male pupal brain through in situ hybridization experiments. Small interfering RNA (siRNA)-mediated knockdown studies were used to assess the putative role of Doublesex, a terminal component of the sex determination pathway, in the regulation of sex-specific gene expression observed in the developing pupal brain.ResultsTranscripts (2,527), many of which were linked to proteolysis, the proteasome, metabolism, catabolic, and biosynthetic processes, ion transport, cell growth, and proliferation, were found to be differentially expressed in A. aegypti female vs. male pupal heads. Analysis of the spatial expression patterns for a subset of dimorphically expressed genes in the pupal brain validated the data set and also facilitated the identification of brain regions with dimorphic gene expression. In many cases, dimorphic gene expression localized to the optic lobe. Sex-specific differences in gene expression were also detected in the antennal lobe and mushroom body. siRNA-mediated gene targeting experiments demonstrated that Doublesex, a transcription factor with consensus binding sites located adjacent to many dimorphically expressed transcripts that function in neural development, is required for regulation of sex-specific gene expression in the developing A. aegypti brain.ConclusionsThese studies revealed sex-specific gene expression profiles in the developing A. aegypti pupal head and identified Doublesex as a key regulator of sexually dimorphic gene expression during mosquito neural development.

Identification of genes related to beak deformity of chickens using digital gene expression profiling.

Frequencies of up to 3% of beak deformity (normally a crossed beak) occur in some indigenous chickens in China, such as and Beijing-You. Chickens with deformed beaks have reduced feed intake, growth rate, and abnormal behaviors. Beak deformity represents an economic as well as an animal welfare problem in the poultry industry. Because the genetic basis of beak deformity remains incompletely understood, the present study sought to identify important genes and metabolic pathways involved in this phenotype. Digital gene expression analysis was performed on deformed and normal beaks collected from Beijing-You chickens to detect global gene expression differences. A total of >11 million cDNA tags were sequenced, and 5,864,499 and 5,648,877 clean tags were obtained in the libraries of deformed and normal beaks, respectively. In total, 1,156 differentially expressed genes (DEG) were identified in the deformed beak with 409 being up-regulated and 747 down-regulated in the deformed beaks. qRT-PCR using eight genes was performed to verify the results of DGE profiling. Gene ontology (GO) analysis highlighted that genes of the keratin family on GGA25 were abundant among the DEGs. Pathway analysis showed that many DEGs were linked to the biosynthesis of unsaturated fatty acids and glycerolipid metabolism. Combining the analyses, 11 genes (MUC, LOC426217, BMP4, ACAA1, LPL, ALDH7A1, GLA, RETSAT, SDR16C5, WWOX, and MOGAT1) were highlighted as potential candidate genes for beak deformity in chickens. Some of these genes have been identified previously, while others have unknown function with respect to thus phenotype. To the best of our knowledge, this is the first genome-wide study to investigate the transcriptome differences in the deformed and normal beaks of chickens. The DEGs identified here are worthy of further functional characterization.

Changes in Adipose mRNA Expression between Previously Laminitic Ponies and Nonlaminitic Ponies in Summer and Winter

Reasons for performing studySome ponies are predisposed to recurrent pasture‐associated laminitis, but the mechanisms underlying this remain unclear. Adipose tissue is a highly metabolically active tissue that secretes mediators which affect vascular function, insulin signalling and inflammation, all of which are potentially implicated in the pathogenesis of laminitis.ObjectivesTo determine whether the gene expression of adipose tissue from previously laminitic ponies (LP) differs from nonlaminitic ponies (NL).Study designSubcutaneous adipose tissue was collected by biopsy from the neck region of healthy LP and NL (n = 6 each group) in the summer and winter.MethodsGene expression was determined using a 44 K equine expression microarray. Data were analysed using GeneSpring and Ingenuity Pathway Analysis. Genes with &gt;2‐fold difference, P&lt;0.01 were considered significant using a t test to analyse group and/or season.ResultsThe most significant differences in global gene expression in adipose tissue were observed between summer and winter in both groups, with 244 (NL) and 174 (LP) genes differentially expressed. There was a significant difference between LP and NL groups in the summer (141 genes differentially expressed), whereas the 2 groups were more similar in the winter (40 genes differentially expressed). Eight of the top 10 upregulated genes and 3 of the top 5 canonical pathways that differed between LP and NL in the summer were associated with inflammation and/or immunity.ConclusionsLaminitic ponies appear to have a different adipose tissue gene expression profile to NL, particularly in the summer. Inflammatory genes and pathways were significantly upregulated in the LP group suggesting higher levels of inflammation or priming of inflammatory pathways which may contribute to a predisposition to laminitis.Ethical animal research: The study was completed under Home Office Project Licence approved by the RVC Ethics and Welfare Committee. Sources of funding: This study was funded by Waltham®. A. Timpson is funded by the Mellon Equine Endowment Fund. Competing interests: Dr P. Harris is employed by Waltham. The other authors have declared no competing interests.

Ontology analysis of global gene expression differences of human bone marrow stromal cells cultured on 3D scaffolds or 2D films

Differences in gene expression of human bone marrow stromal cells (hBMSCs) during culture in three-dimensional (3D) nanofiber scaffolds or on two-dimensional (2D) films were investigated via pathway analysis of microarray mRNA expression profiles. Previous work has shown that hBMSC culture in nanofiber scaffolds can induce osteogenic differentiation in the absence of osteogenic supplements (OS). Analysis using ontology databases revealed that nanofibers and OS regulated similar pathways and that both were enriched for TGF-β and cell-adhesion/ECM-receptor pathways. The most notable difference between the two was that nanofibers had stronger enrichment for cell-adhesion/ECM-receptor pathways. Comparison of nanofibers scaffolds with flat films yielded stronger differences in gene expression than comparison of nanofibers made from different polymers, suggesting that substrate structure had stronger effects on cell function than substrate polymer composition. These results demonstrate that physical (nanofibers) and biochemical (OS) signals regulate similar ontological pathways, suggesting that these cues use similar molecular mechanisms to control hBMSC differentiation.

ImmuSort, a database on dynamic gene expression and electronic sorting of immune cells (TECH1P.840)

Abstract With abundance of accumulated public biological data, it is worthy of consideration about how to fully use these data for wet-experiments. In the current study, we built an immunological database, ImmuSort. ImmuSort provides a convenient way to view global differential gene expression across various experimental conditions or disease states in immune cells, and enables an electronic sorting of these cells in association with a certain expressional intensity. Meanwhile, gene plasticity, comparison of expression level, biomarker discovery and valuation, identification of cell specific transcripts, etc., can also be accessible in the database. Importantly, ImmuSort database can contribute to the discovery of potential novel functional populations of immune cells, e.g., the association of CCL20 bright myeloid populations with inflammation, and provide clues for the function of human and mouse genes in the immune system. ImmuSort is the first product of our immunological database development project. It can be freely accessed on the web at http://202.85.212.211/Account/ImmuSort.html.

Deep transcriptome sequencing reveals differences in global gene expression between normal and pale, soft, and exudative turkey meat1

Previous studies from our laboratory suggested that differential expression of genes between normal and pale, soft, and exudative (PSE) turkey is associated with development of the PSE syndrome. However, a detailed understanding of molecular mechanisms responsible for the development of this meat defect remains unclear. The objective of this study was to extend and complement our previous work by using deep transcriptome RNA sequence analysis to compare the respective transcriptome profiles and identify molecular mechanisms responsible for the etiology of PSE turkey meat. Turkey breasts (n = 43) were previously classified as normal or PSE using marinade uptake as an indicator of quality (high = normal; low = PSE). Total RNA from breast muscle samples with the highest (n = 4) and lowest (n = 4) marinade uptake were isolated and sequenced using the Illumina GA(IIX) platform. The results indicated differential expression of 494 loci (false discovery rate < 0.05). Changes in gene expression were confirmed using quantitative real-time PCR. Pathway analysis of differentially expressed genes suggested abnormalities of calcium homeostasis and signaling pathways regulating actin cytoskeleton structure as well as carbohydrate metabolism and energy production in PSE samples. Dysregulation of postmortem glucose oxidation in PSE turkey was suggested by both dramatic downregulation of pyruvate dehydrogenase kinase, isozyme 4 (PDK4) mRNA, the most downregulated gene, and a decrease in the protein product (P = 0.0007) as determined by immunoblot analysis. These results support the hypothesis that differential expression of several genes and their protein products contribute to development of PSE turkey.

Comparative transcriptome analysis of obligately asexual and cyclically sexual rotifers reveals genes with putative functions in sexual reproduction, dormancy, and asexual egg production

BackgroundSexual reproduction is a widely studied biological process because it is critically important to the genetics, evolution, and ecology of eukaryotes. Despite decades of study on this topic, no comprehensive explanation has been accepted that explains the evolutionary forces underlying its prevalence and persistence in nature. Monogonont rotifers offer a useful system for experimental studies relating to the evolution of sexual reproduction due to their rapid reproductive rate and close relationship to the putatively ancient asexual bdelloid rotifers. However, little is known about the molecular underpinnings of sex in any rotifer species.ResultsWe generated mRNA-seq libraries for obligate parthenogenetic (OP) and cyclical parthenogenetic (CP) strains of the monogonont rotifer, Brachionus calyciflorus, to identify genes specific to both modes of reproduction. Our differential expression analysis identified receptors with putative roles in signaling pathways responsible for the transition from asexual to sexual reproduction. Differential expression of a specific copy of the duplicated cell cycle regulatory gene CDC20 and specific copies of histone H2A suggest that such duplications may underlie the phenotypic plasticity required for reproductive mode switch in monogononts. We further identified differential expression of genes involved in the formation of resting eggs, a process linked exclusively to sex in this species. Finally, we identified transcripts from the bdelloid rotifer Adineta ricciae that have significant sequence similarity to genes with higher expression in CP strains of B. calyciflorus.ConclusionsOur analysis of global gene expression differences between facultatively sexual and exclusively asexual populations of B. calyciflorus provides insights into the molecular nature of sexual reproduction in rotifers. Furthermore, our results offer insight into the evolution of obligate asexuality in bdelloid rotifers and provide indicators important for the use of monogononts as a model system for investigating the evolution of sexual reproduction.

Transcript expression in endometrial cancers from Black and White patients

ObjectivePrevious studies suggest that differences in molecular features of endometrial cancers between racial groups may contribute to the poorer survival in Blacks. The objective of this investigation was to determine whether gene expression among endometrial cancers is different between Blacks and Whites. MethodsFresh frozen tumors from 25 Black patients were matched by stage, grade, and histology to endometrial cancer specimens from 25 White patients. Each case was macrodissected to produce specimens possessing a minimum of 75% cancer cellularity. A subset of 10 matched pairs was also prepared using laser microdissection (LMD) to produce specimens possessing a minimum of 95% cancer cells. Total RNA isolated from each sample was analyzed using the Affymetrix Human Genome U133 Plus 2.0 arrays. Data were analyzed using principal component analysis and binary class comparison analyses. ResultsUnsupervised analysis of the 50 endometrial cancers failed to identify global gene expression profiles unique to Black or White patients. In a subset analysis of 10 matched pairs from Blacks and Whites prepared using LMD and macrodissection, unsupervised analysis did not reveal a unique gene expression profile associated with race in either set, but associations were identified that relate to sample preparation technique, histology and stage. ConclusionsOur microarray data revealed no global gene expression differences and identified few individual gene differences between endometrial cancers from Blacks and Whites. More comprehensive methods of transcriptome analysis could uncover RNAs that may underpin the disparity of outcome or prevalence of endometrial cancers in Blacks and Whites.

Depot differences in gene expression in response to dexamethasone in human adipose tissue

Hypercortisolemia leads to a preferential fat deposition in visceral adipose tissues. We previously noted that the glucocorticoid receptor agonist dexamethasone (Dex, 25 nM) regulated many metabolic and inflammatory gene pathways in human omental (Om) and abdominal subcutaneous (Sc) adipose tissues. To determine whether differential sensitivity to Dex contributes to depot differences in global gene expression, fragments of Sc and Om adipose tissues from severely obese females (n=3) were cultured in the presence of 7nM insulin plus 0 (control), 1, 10, or 1000 nM Dex for 7 days. 1 and 10 nM Dex regulated, respectively, 88 and 414 genes in Om, and 173 and 594 genes in Sc by 2‐fold or more. Thus, almost 2‐fold more genes were regulated by Dex in Sc than Om at low Dex. We noted and confirmed by qPCR that INHBA, a gene known to inhibit adipogenesis, was ~6‐fold higher in Om and was suppressed in both, but remained higher in Om at Dex 1 and 10 nM. In primary cultured predipocytes (n=3), INHBA was similar in confluent preadipocytes, but was less suppressed when a standard differentiation cocktail containing Dex was added. At day 14 of differentiation, INHBA expression was ~50‐fold higher in Om cultures in parallel to poorer differentiation. Overall, our data suggest that differential sensitivity to physiologically relevant concentrations of Dex can contribute to depot differences in adipocyte differentiation and function.