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[Gene expression profile of yolk sac and fetal liver in mouse].

OBJECTIVE: To better understand the mechanisms of the fetal hematopoiesis turn over from primitive to definitive hematopoiesis through the expression level of c-kit(+) and sca-1(+), and major characters of gene expression profile of these cells. METHODS: c-kit and sca-1 expression level were monitored with fluorescence activated cell sorting (FACS) of the mononuclear cells from mouse yolk sac and fetal liver, while gene expression profile was carried out with EST sequencing strategy. RESULTS: The Sca-1(+) cells were increased while the c-kit(+) cells decreased with the embryonic development. Through profiling the functionally identified known genes, most of the highly expressed were globin genes, especially of embryonic types. CONCLUSION: The erythropoiesis played a key role in early fetal hematopoiesis in mammalian.

Animals↗

Gene expression profiling reveals the profound upregulation of hypoxia-responsive genes in primary human astrocytes.

Oxygen is vital for the development and survival of mammals. In response to hypoxia, the brain initiates numerous adaptive responses at the organ level as well as at the molecular and cellular levels, including the alteration of gene expression. Astrocytes play critical roles in the proper functioning of the brain; thus the manner in which astrocytes respond to hypoxia is likely important in determining the outcome of brain hypoxia. Here, we used microarray gene expression profiling and data-analysis algorithms to identify and analyze hypoxia-responsive genes in primary human astrocytes. We also compared gene expression patterns in astrocytes with those in human HeLa cells and pulmonary artery endothelial cells (ECs). Remarkably, in astrocytes, five times as many genes were induced as suppressed, whereas in HeLa and pulmonary ECs, as many as or more genes were suppressed than induced. More genes encoding hypoxia-inducible functions, such as glycolytic enzymes and angiogenic growth factors, were strongly induced in astrocytes compared with HeLa cells. Furthermore, gene ontology and computational algorithms revealed that many target genes of the EGF and insulin signaling pathways and the transcriptional regulators Myc, Jun, and p53 were selectively altered by hypoxia in astrocytes. Indeed, Western blot analysis confirmed that two major signal transducers mediating insulin and EGF action, Akt and MEK1/2, were activated by hypoxia in astrocytes. These results provide a global view of the signaling and regulatory network mediating oxygen regulation in human astrocytes.

Algorithms↗

Correlation of protein and gene expression profiles of inflammatory proteins after endotoxin challenge in human subjects.

Administration of endotoxin (LPS) in humans results in profound physiological responses, including activation of peripheral blood mononuclear cells and the release of inflammatory factors. The time course of the response of selected inflammatory proteins was examined in healthy subjects (n = 6) administered a single intravenous dose of the purified derivative of endotoxin (3.0 ng/kg). Microarray analysis demonstrated changes in the expression of a number of genes, which were confirmed in separate in vitro endotoxin stimulation experiments. Subsequent TaqMan analysis of genes of interest indicated time-dependent changes in the expression of many of these genes. This included pre-B cell enhancing factor, which was identified on microarray analysis as being markedly upregulated following endotoxin stimulation. Protein expression of the genes examined by TaqMan analysis was measured and demonstrated the appearance of tumor necrosis factor (TNF)-alpha and sTNF-R proteins in the plasma beginning within 1 h after dosing, followed by other cytokines/ inflammatory markers (e.g., IL-1ra, G-CSF, IL-6, IL-8, and IL-10) and suppressors of cytokine signaling (SOCS-1 and SOCS-3). In general, cytokine protein expression correlated well with gene expression; however, the temporal profile of expression of some genes did not correlate well with the protein data. For many of these proteins, the lack of correlation was attributable to alternate tissue sources, which were demonstrated on TaqMan analysis. Principal component analysis indicated that cytokines could be grouped according to their temporal pattern of response, with most transcript levels returning to baseline 24 h following endotoxin administration. The combination of cDNA microarray and TaqMan analysis to identify and quantify changes in gene expression, along with the analysis of protein expression, can be useful in investigating inflammatory and other diseases.

Adolescent↗

Regulation of the estrogen-inducible gene expression profile by the breast cancer susceptibility gene BRCA1.

The tumor suppressor gene BRCA1 functions in part as a caretaker in preserving the integrity of the genome, but also exhibits tissue-specific function by inhibiting estrogen receptor activity. Because estrogen (E2) induces a wide range of gene expression changes (by nongenomic and several transcriptional pathways), we sought to determine how comprehensive is the BRCA1-mediated inhibition of E2-induced gene expression alterations. Using cDNA-spotted microarrays, we identified a relatively large number of gene expression alterations (both increased and decreased expression) in MCF-7 cells caused by E2, some of which have been reported in previous studies. However, in the presence of exogenous wild-type BRCA1 (wtBRCA1), the response to E2 was severely blunted, with only about 10% the number of gene expression changes as that found in the absence of wtBRCA1. Examples of these findings were confirmed by semiquantitative and quantitative RT-PCR assays. In contrast to wtBRCA1, the induction by E2 of several E2-responsive genes was not inhibited by a full-length tumor-associated mutant BRCA1 protein [T300G (or (61)Cys-->Gly)]. For three E2-responsive genes whose induction by E2 was inhibited by wtBRCA1, wtBRCA1 had little or no effect on the mRNA half-life in the presence of E2. Consistent with these findings, wtBRCA1 inhibited E2-stimulated proliferation of MCF-7 cells, but wtBRCA1 failed to inhibit the proliferation of MCF-7 cells stimulated by IGF-I. Our findings suggest that BRCA1 globally inhibits the response to estrogen in a dose- and time-dependent fashion. The implications of these findings for understanding how BRCA1 may act to restrain E2 action in vivo are considered.

Cell Line, Tumor↗

Acute ozone-induced differential gene expression profiles in rat lung.

Ozone is an oxidant gas that can directly induce lung injury. Knowledge of the initial molecular events of the acute O3 response would be useful in developing biomarkers of exposure or response. Toward this goal, we exposed rats to toxic concentrations of O3 (2 and 5 ppm) for 2 hr and the molecular changes were assessed in lung tissue 2 hr postexposure using a rat cDNA expression array containing 588 characterized genes. Gene array analysis indicated differential expression in almost equal numbers of genes for the two exposure groups: 62 at 2 ppm and 57 at 5 ppm. Most of these genes were common to both exposure groups, suggesting common roles in the initial toxicity response. However, we also identified the induction of nine genes specific to 2-ppm (thyroid hormone-beta receptor c-erb-A-beta; and glutathione reductase) or 5-ppm exposure groups (c-jun, induced nitric oxide synthase, macrophage inflammatory protein-2, and heat shock protein 27). Injury markers in bronchoalveolar lavage fluid (BALF) were used to assess immediate toxicity and inflammation in rats similarly exposed. At 2 ppm, injury was marked by significant increases in BALF total protein, N-acetylglucosaminidase, and lavageable ciliated cells. Because infiltration of neutrophils was observed only at the higher 5 ppm concentration, the distinctive genes suggested a potential amplification role for inflammation in the gene profile. Although the specific gene interactions remain unclear, this is the first report indicating a dose-dependent direct and immediate induction of gene expression that may be separate from those genes involved in inflammation after acute O3 exposure.

Administration, Inhalation↗

15000 unique zebrafish EST clusters and their future use in microarray for profiling gene expression patterns during embryogenesis.

A total of 15590 unique zebrafish EST clusters from two cDNA libraries have been identified. Most significantly, only 22% (3437) of the 15590 unique clusters matched 2805 (of 15200) clusters in the Danio rerio UniGene database, indicating that our EST set is complementary to the existing ESTs in the public database and will be invaluable in assisting the annotation of genes based on the upcoming zebrafish genome sequence. Blast search showed that 7824 of our unique clusters matched 6710 known or predicted proteins in the nonredundant database. A cDNA microarray representing approximately 3100 unique zebrafish cDNA clusters has been generated and used to profile the gene expression patterns across six different embryonic stages (cleavage, blastula, gastrula, segmentation, pharyngula, and hatching). Analysis of expression data using K-means clustering revealed that genes coding for muscle-specific proteins displayed similar expression patterns, confirming that the coordinate gene expression is important for myogenesis. Our results demonstrate that the combination of microarray technology with the zebrafish model system can provide useful information on how genes are coordinated in a genetic network to control zebrafish embryogenesis and can help to identify novel genes that are important for organogenesis.

Animals↗

Gene expression profiling identifies markers of ampullary adenocarcinoma.

Ampullary adenocarcinoma is an aggressive cancer with a poor prognosis. Without surgical resection, ampullary adenocarcinomas can be difficult to distinguish from ampullary adenomas. The aim of this study was to identify differentially expressed genes in ampullary adenocarcinoma in order to identify candidate markers of the disease. The Affymetrix Human Genome U133 GeneChip set (HG-U133A and HG-U133B) was used to obtain gene expression profiles of 5 ampullary adenocarcinomas and 10 normal duodenal samples. Using fold change analysis we identified 235 fragments expressed at least fivefold higher in ampullary cancers than in normal duodenum. The expression profiles of eight candidate overexpressed genes (osteopontin, mesothelin, tissue inhibitor of metalloproteinases 1, mucin-1, mucin-5, fascin, heat shock protein 47, fibronectin 1) were confirmed by immunohistochemistry or in situ hybridization on tissue microarrays (TMA) containing 54 ampullary adenocarcinomas. One of these genes, osteopontin, was expressed 27-fold higher levels in ampullary adenocarcinomas compared to normal duodenum by genechip analysis. We therefore determined serum osteopontin levels in patients with ampullary neoplasms, patients with other periampullary diseases and in normal controls. Mean preoperative serum osteopontin levels as measured by competitive ELISA were 906 +/- 268 ng/ml in patients with ampullary cancer, 867 +/- 160 ng/ml in patients with an ampullary adenoma, 327.1 +/- 195.6 ng/ml in patients with nonmalignant periampullary diseases and 204 +/- 65 ng/ml in age-matched healthy controls (p < 0.001). Measurement of markers of ampullary cancer such as osteopontin may aid in the early detection and differential diagnosis of patients with periampullary lesions.

Adenocarcinoma↗

Genome-wide cDNA microarray screening to correlate gene expression profile with survival in patients with advanced lung cancer.

We conducted a study using cDNA microarray analysis to determine whether expression levels of genes in tumors were correlated with survival after chemotherapy. Between September 2000 and December 2001, 47 patients were registered in the study. Eighteen patients had small cell lung cancer (SCLC), and the others had non-small cell lung cancer (NSCLC). All patients except three received platinum-based chemotherapy. Transbroncheal biopsy specimens of tumors were obtained before chemotherapy. The expression levels of 1176 genes in tumor specimens were analyzed using the Atlas Human Cancer 1.2 Array. The expression levels of three genes, G1/S-specific cyclin, type II cGMP-dependent protein kinase and hepatocyte growth factor-like protein, were significantly correlated with survival (p<0.01). Ten of the 47 patients who showed an elevated expression level of one or more of the three genes had a significantly increased chance of survival (p=0.0056). In conclusion, some survival-related genes were detected in the tumor tissue of lung cancer patients using cDNA microarray analysis. A prospective study is required to confirm whether expression levels of these genes can be used for prognosis.

Carcinoma, Non-Small-Cell Lung↗

Gene expression profiles associated with treatment response in oligodendrogliomas.

Oligodendrogliomas are a specific subtype of brain tumor of which the majority responds favorably to chemotherapy. In this study, we made use of expression profiling to identify chemosensitive oligodendroglial tumors. Correlation of expression profiles to loss of heterozygosity on 1p and 19q, common chromosomal aberrations associated with response to treatment, identified 376, 64, and 60 differentially expressed probe sets associated with loss of 1p, 19q or 1p, and 19q, respectively. Correlation of expression profiles to the tumors' response to treatment identified 16 differentially expressed probe sets. Because transcripts associated with chemotherapeutic response were identified independent of common chromosomal aberrations, expression profiling may be used as an alternative approach to the tumors' 1p status to identify chemosensitive oligodendroglial tumors. Finally, we correlated expression profiles to survival of the patient after diagnosis and identified 103 differentially expressed probe sets. The observation that many genes are differentially expressed between long and short survivors indicates that the genetic background of the tumor is an important factor in determining the prognosis of the patient. Furthermore, these transcripts can help identify patient subgroups that are associated with favorable prognosis. Our study is the first to correlate gene expression with chromosomal aberrations and clinical performance (response to treatment and survival) in oligodendrogliomas. The differentially expressed transcripts can help identify patient subgroups with good prognosis and those that will benefit from chemotherapeutic treatments.

Adult↗

Gene expression profiles of transcription factors and signaling molecules in the ascidian embryo: towards a comprehensive understanding of gene networks.

Achieving a real understanding of animal development obviously requires a comprehensive rather than partial identification of the genes working in each developmental process. Recent decoding of genome sequences will enable us to perform such studies. An ascidian, Ciona intestinalis, one of the animals whose genome has been sequenced, is a chordate sharing a basic body plan with vertebrates, although its genome contains less paralogs than are usually seen in vertebrates. In the present study, we discuss the genomewide approach to networks of developmental genes in Ciona embryos. We focus on transcription factor genes and some major groups of signal transduction genes. These genes are comprehensively listed and examined with regard to their embryonic expression by in situ hybridization (http://ghost.zool.kyoto-u.ac.jp/tfst.html). The results revealed that 74% of the transcription factor genes are expressed maternally and that 56% of the genes are zygotically expressed during embryogenesis. Of these, 34% of the transcription factor genes are expressed both maternally and zygotically. The number of zygotically expressed transcription factor genes increases gradually during embryogenesis. As an example, and taking advantage of this comprehensive description of gene expression profiles, we identified transcription factor genes and signal transduction genes that are expressed at the early gastrula stage and that work downstream of beta-catenin, FoxD and/or Fgf9/16/20. Because these three genes are essential for ascidian endomesoderm specification, transcription factor genes and signal transduction genes involved in each of the downstream processes can be deduced comprehensively using the present approach.

Animals↗

Gene-expression profile comparisons distinguish seven organs of maize.

BACKGROUND: A maize array was fabricated with 5,376 unique expressed sequence tag (EST) clones sequenced from 4-day-old roots, immature ears and adult organ cDNA libraries. To elucidate organ relationships, relative mRNA levels were quantified by hybridization with embryos, three maize vegetative organs (leaf blades, leaf sheaths and roots) from multiple developmental stages, husk leaves and two types of floral organs (immature ears and silks). RESULTS: Clustering analyses of the hybridization data suggest that maize utilizes both the PEPCK and NADP-ME C(4) photosynthetic routes as genes in these pathways are co-regulated. Husk RNA has a gene-expression profile more similar to floral organs than to vegetative leaves. Only 7% of the genes were highly organ specific, showing over a fourfold difference in at least one of 12 comparisons and 37% showed a two- to fourfold difference. The majority of genes were expressed in diverse organs with little difference in transcript levels. Cross-hybridization among closely related genes within multigene families could obscure tissue specificity. As a first step in elucidating individual gene-expression patterns, we show that 45-nucleotide oligo probes produce signal intensities and signal ratios comparable to PCR probes on the same matrix. CONCLUSIONS: Gene-expression profile studies with cDNA microarrays provide a new molecular tool for defining plant organs and their relationships and for discovering new biological processes in silico. cDNA microarrays are insufficient for differentiating recently duplicated genes. Gene-specific oligo probes printed along with cDNA probes can query individual gene-expression profiles and gene families simultaneously.

Cluster Analysis↗

Cardiac function-related gene expression profiles in human atrial myocytes.

To obtain insights into the molecular pathogenesis of heart failure in humans, we have analyzed the expression profiles of>12,000 genes in a total of 17 human specimens of right atrial myocytes. From this large data set, we here tried to identify gene clusters, expression level of which is correlated precisely with clinical parameter values of cardiac function. We could reveal that cardiac myocytes with normal sinus rhythm were clearly differentiated, in the point of view of gene expression, from those with atrial fibrillation. Further, an expression profile-based prediction of arrhythmia by a newly developed "weighted-distance method" could efficiently diagnose our samples. We could even construct calculation formulae for the values of left ventricular ejection fraction based on the expression level of selected genes. To our best knowledge, this is the first report to indicate that pumping ability of heart can be predicted by any measures of atrium.

Adolescent↗

Gene expression profiles in human cardiac cells subjected to hypoxia or expressing a hybrid form of HIF-1 alpha.

The cellular response to hypoxia depends on rapid posttranslational modifications of proteins as well as regulation of gene expression. We performed serial analysis of gene expression (SAGE) on human cardiac cells under normoxia, subjected to hypoxia, or infected with Ad2/HIF-1alpha/VP16 (an adenoviral vector expressing a stable hybrid form of hypoxia-inducible factor 1alpha) or Ad2/CMVEV (an empty vector). Of the 97,646 SAGE tags that were sequenced, 27% matched GenBank entries, while an additional 32% matched expressed sequence tags (ESTs) in UniGene. We analyzed 161 characterized genes or ESTs with a putative identification. Expression of 35, 11, and 46 genes was increased by hypoxia, infection with Ad2/EVCMV, or infection with Ad2/HIF-1alpha/VP16, respectively, compared with normoxia; conversely, 20, 11, 38 genes, respectively, were expressed at lower levels. Genes regulated by hypoxia were associated with transcription, biosynthesis, extracellular matrix formation, glycolysis, energy production, cell survival, and cell stress. Changes following infection with Ad2/HIF-1alpha/VP16 mimicked the hypoxic response to a certain extent. Infection with Ad2/CMVEV affected expression of genes that were associated with extracellular matrix formation and membrane trafficking. Differential expression of select genes was confirmed using TaqMan in additional human cardiac cells and rat neonatal ventricular myocytes. These data provide insight into gene expression underlying the diverse and complex cellular response to hypoxia, expression of HIF-1alpha/VP16, or adenoviral infection.

Adenoviridae↗

Neonatal and adult CD4+ CD3- cells share similar gene expression profile, and neonatal cells up-regulate OX40 ligand in response to TL1A (TNFSF15).

We report here the quantitative expression of a set of immunity-related genes, including TNF family members, chemokine receptors, and transcription factors, in a CD4+ CD3- accessory cell. By correlating gene expression between cell-sorted populations of defined phenotype, we show that the genetic fingerprint of these CD4+ CD3- cells is distinct from dendritic cells, plasmacytoid dendritic cells, T cells, B cells, and NK cells. In contrast, it is highly similar to CD4+ CD3- cells isolated from embryonic and neonatal tissues, with the exception that only adult populations express OX40L and CD30L. We have previously reported that IL-7 signals regulate CD30L expression. In the present study, we show that both neonatal and adult CD4+ CD3- cells express the TNF family member, death receptor 3 (TNFRSF25), and that addition of TL1A (TNFSF15), the ligand for death receptor 3, up-regulates OX40L on neonatal CD4+ CD3- cells. Finally, we demonstrate that this differentiation occurs in vivo: neonatal CD4+ CD3- cells up-regulate both CD30L and OX40L after adoptive transfer into an adult recipient.

Aging↗

Rules for gene usage inferred from a comparison of large-scale gene expression profiles of T and B lymphocyte development.

Ribonucleic acid expression profiles of seven consecutive stages of mouse thymocyte development were generated on high density oligonucleotide arrays. Previously known expression patterns of several genes were confirmed. Ten percent (1,304 of more than 13,000) of the monitored genes were found with 99% confidence to be differentially expressed across all T cell developmental stages. When compared with 1,204 genes differentially expressed in five consecutive B lineage developmental stages of bone marrow, >40% (546 genes) appeared to be shared by both lineages. However, when four pools of functionally distinct cell stages were compared between B and T cell development, DJ-rearranged precursor cells and resting immature precursor cells before and after surface Ag receptor expression shared less than 10%, mature resting lymphocytes between 15 and 20%, and only cycling precursors responding to precursor lymphocyte receptor deposition shared >50% of these differentially expressed genes. Three general rules emerge from these results: 1) proliferation of cells at comparable stages is in majority executed by the same genes; 2) intracellular signaling and intercellular communication are effected largely by different genes; and 3) most genes are not used strictly at comparable, but rather at several, stages, possibly in different functional contexts.

Animals↗

Gene expression profiling of differentially expressed genes in granulosa cells of bovine dominant follicles using suppression subtractive hybridization.

Development of antral follicles beyond 3 to 4 mm in cattle appears as a wave pattern that occurs two to three times during the estrous cycle. Each wave presents a cyclic recruitment of multiple follicles at the 3- to 4-mm stage, followed by the selection of a single follicle that becomes the dominant follicle (DF). The molecular determinants involved in the follicular dominance process remain poorly understood. The objective of the current study was to compare gene expression in granulosa cells (GCs) between growing dominant follicles from Day 5 of the estrous cycle and nonselected small follicles (<or=4 mm) using the suppression subtractive hybridization (SSH) approach to identify candidate genes differentially expressed in GCs of the DF. Small follicle cDNAs were subtracted from DF cDNAs (DF-SF) and used to establish a DF GC-subtracted cDNA library. A total of 42 nonredundant cDNAs were identified. Detection of previously identified genes such as CX43, CYP19, INHBA, and SERPINE2 supported the validity of our experimental model and the use of SSH as the method of analysis. For selected genes such as ApoER2, CPD, CSPG2, 14-3-3 epsilon, NR5A2/SF2, RGN/SMP30, and SERPINE2, gene expression profiles were compared by virtual Northern blot or reverse transcriptase-polymerase chain reaction, and results confirmed an increase or induction of their mRNA in GCs of dominant follicles compared with that of small follicles. We conclude that we have identified novel genes (known and unknown) that are up-regulated in bovine GCs that may affect follicular growth, dominance, or both.

Animals↗

Gene expression profiling by DNA microarrays and metabolic fluxes in Escherichia coli.

DNA microarray technology was applied to detect differential transcription profiles of a subset of the Escherichia coli genome. A total of 111 E. coli genes, including those in central metabolism, key biosyntheses, and some regulatory functions, were cloned, amplified, and used as probes for detecting the level of transcripts. An E. coli strain was grown in glucose, acetate, and glycerol media, and the transcript levels of the selected genes were detected. Despite extensive studies on E. coli physiology, many new features were found in the regulation of these genes. For example, several genes were unexpectedly up-regulated, such as pps, ilvG, aroF, secA, and dsbA in acetate and asnA and asnB in glycerol, or down-regulated, such as ackA, pta, and adhE in acetate. These genes were regulated with no apparent reasons by unknown mechanisms. Meanwhile, many genes were regulated for apparent purposes but by unknown mechanisms. For example, the glucose transport genes (ptsHI, ptsG, crr) in both acetate and glycerol media were down-regulated, and the ppc, glycolytic, and biosynthetic genes in acetate were also down-regulated because of the reduced fluxes. However, their molecular mechanisms remain to be elucidated. Furthermore, a group of genes were regulated by known mechanisms, but the physiological roles of such regulation remain unclear. This group includes pckA and aspA, which are up-regulated in glycerol, and gnd and aspA, which are down- and up-regulated, respectively, in acetate. The DNA microarray technology demonstrated here is a powerful yet economical tool for characterizing gene regulation and will prove to be useful for strain improvement and bioprocess development.

Carbon↗

Do aberrant crypt foci have predictive value for the occurrence of colorectal tumours? Potential of gene expression profiling in tumours.

The effects of different dietary compounds on the formation of aberrant crypt foci (ACF) and colorectal tumours and on the expression of a selection of genes were studied in rats. Azoxymethane-treated male F344 rats were fed either a control diet or a diet containing 10% wheat bran (WB), 0.2% curcumin (CUR), 4% rutin (RUT) or 0.04% benzyl isothiocyanate (BIT) for 8 months. ACF were counted after 7, 15 and 26 weeks. Tumours were scored after 26 weeks and 8 months. We found that the WB and CUR diets inhibited the development of colorectal tumours. In contrast, the RUT and BIT diets rather enhanced (although not statistically significantly) colorectal carcinogenesis. In addition, the various compounds caused different effects on the development of ACF. In most cases the number or size of ACF was not predictive for the ultimate tumour yield. The expression of some tumour-related genes was significantly different in tumours from the control group as compared to tumours from the treated groups. It was concluded that WB and CUR, as opposed to RUT and BIT, protects against colorectal cancer and that ACF are unsuitable as biomarker for colorectal cancer. Effects of the different dietary compounds on metalloproteinase 1 (TIMP-1) expression correlated well with the effects of the dietary compounds on the ultimate tumour yield.

Animals↗