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PubMed2003

Expression profile and cellular localization of maize Rpd3-type histone deacetylases during plant development.

We analyzed the expression profile and cellular localization of the maize (Zea mays) Rpd3-type histone deacetylases genes ZmRpd3/101, ZmRpd3/102, and ZmRpd3/108 (indicated as ZmHDA101, ZmHDA102, and ZmHDA108 in the Plant Chromatin Database). This study shows that maize Rpd3 transcripts are present in all the organs and cellular domains analyzed, but we found that their amounts change during development, accumulating in the inner region of the endosperm, in vascular zones of the nucellus, in the tapetum, and in the tetrads. A similar expression profile and nucleus-cytoplasmic localization was observed for ZmRpd3 proteins. Glutathione S-transferase pull-down assays show that ZmRpd3 proteins can interact with the maize retinoblastoma-related (ZmRBR1) protein, an important regulator of cell cycle progression, and with the maize retinoblastoma-associated protein (ZmRbAp1). However, the three ZmRpd3 proteins do not mutually compete in the binding. These results suggest a general role of ZmRpd3 genes in the plant cell cycle and development. These observations also provide indications on possible mechanisms regulating their transcription and protein accumulation. Similarities in the gene expression profiles and protein interactions may indicate that functional redundancy among members of the ZmRpd3 gene family exists. However, a degree of functional divergence is also supported by our findings.

Amino Acid Sequence↗
PubMed2004

Monitoring of gene expression profiles and isolation of candidate genes involved in pollination and fertilization in rice ( Oryza sativa L.) with a 10K cDNA microarray.

To monitor gene expression profiles during pollination and fertilization in rice at a genome scale, we generated 73,424 high-quality expressed sequence tags (ESTs) derived from the green/etiolated shoot and pistil (0-5 h after pollination, 5hP) of rice, which were subsequently used to construct a cDNA microarray containing ca. 10 000 unique rice genes. This microarray was used to analyze gene expression in pistil unpollinated (UP), 5hP and 5DAP(5 days after pollination), anther, shoot, root, 10-day-old embryo (10EM) and 10-day-old endosperm (10EN). Clustering analysis revealed that the anther has a gene-expression profile more similar to root than to pistil and most pistil-preferentially expressed genes respond to pollination and/or fertilization. There are 253 ESTs exhibiting differential expression (e +/- 2-fold changes) during pollination and fertilization, and about 70% of them can be assigned a putative function. We also recovered 20 genes similar to pollination-related and/or fertility-related genes previously identified as well as genes that were not implicated previously. Microarray and real-time PCR analyses showed that the array sensitivity was estimated at 1-5 copies of mRNA per cell, and the differentially expressed genes showed a high correlation between the two methods. Our results indicated that this cDNA microarray constructed here is reliable and can be used for monitoring gene expression profiles in rice. In addition, the genes that differentially expressed during pollination represent candidate genes for dissecting molecular mechanism of this important biological process in rice.

Cluster Analysis↗
PubMed2006

Difference of gene expression profiles between Barrett's esophagus and cardia intestinal metaplasia by gene chip.

The difference of gene expression profile changes in Barrett's esophagus (BE) and cardia intestinal metaplasia (CIM) epithelium was studied and the novel associated genes were screened in the early stage by cDNA microarray. The cDNA retro-transcribed from equal quantity mRNA from BE and CIM epithelial tissues were labeled with Cy3 and Cy5 fluorescence as probes. The mixed probe was hybridized with three pieces BiostarH-40s double dot human whole gene chip. The chips were scanned with a ScanArray 4000. The acquired images were analyzed using GenePix Pro 3.0 software. It was found a total of 141 genes were screened out that exhibited differentially expression more than 2 times in all three chips. It was identified that in gene expression profiles of BE, 74 genes were up-regulated and 67 down-regulated as compared with CIM. The comparison between the difference of gene expression profile changes in BE and CIM epithelia revealed that there existed the difference between BE and CIM at gene level. 141 genes with the expression more than two time were probably related to the occurrence and development of BE and the promotion or progress in adenocarcinoma.

Barrett Esophagus↗
PubMed2004

Utilizing Nottingham Prognostic Index in microarray gene expression profiling of breast carcinomas.

We report a novel approach to gene expression profiling using the Nottingham Prognostic Index (NPI) to stratify 26 patients with invasive breast carcinoma. As an aggregate index of parameters reflecting metastatic potential, growth rate, and genetic instability the NPI has distinct advantages over other clinicopathologic features used to segregate breast cancer patients. As a continuous variable it offers a responsive and sensitive means of modeling a continuum of clinical aggressiveness. Using RNA extracted from 26 tumors and cDNA microarrays with 23 343 unique genetic elements, 84 genes and expressed sequence tags were identified whose expression patterns correlated with NPI. Differential expression by immunohistochemistry (IHC) was also observed for two of three genes evaluated by this method. Correlation was determined by the Spearman rank correlation method with null distribution analysis. Among the 84 genetic elements were seven previously implicated in neoplastic progression (including the two demonstrating differential expression by IHC), 11 without specific cancer association but localized to chromosomal sites whose loss or gain has been identified in cytogenetic studies of breast carcinoma, and 73 not previously associated with breast carcinoma. Collectively, the expression patterns of these 84 elements have potential to distinguish high and low NPI patient samples. These data add support to the assertion that prognostic groups of breast carcinoma are reflected in distinguishable expression profiles of a limited set of genes.

Adult↗
PubMed2005

Blood gene expression profiling of neurologic diseases: a pilot microarray study.

BACKGROUND: Tissue gene expression profiling with arrays measures the transcription of thousands of genes. However, this approach cannot be readily used to guide clinical neurologic practice. OBJECTIVES: To determine whether clinical neurologic diseases are associated with unique patterns of up- and down-regulated genes in whole blood and to explore the possibility of using peripheral blood as a surrogate tissue in these diseases. DESIGN: Case-control study. SETTING: University-based pediatric and adult neurology clinics. PARTICIPANTS: Patients with neurofibromatosis type 1, epilepsy, or Tourette syndrome diagnosed using traditional clinical criteria; controls without disease; and controls with neurologic disease. MAIN OUTCOME MEASURE: Blood gene expression levels of greater than 12,000 genes, measured using U95A arrays. RESULTS: Neurofibromatosis type 1 and childhood epilepsy treated with carbamazepine or valproic acid are associated with distinct patterns of blood gene expression. Patients with valproic acid-responsive vs valproic acid-refractory epilepsy formed distinct subclusters. Tourette syndrome was characterized by several gene expression clusters. In 1 cluster, 6 genes-all associated with immune cell function-were overexpressed. CONCLUSION: Blood gene expression profiling can provide surrogate markers for neurologic diseases without obvious blood phenotypes.

Adolescent↗
PubMed2007

Prediction of metastasis from low-malignant breast cancer by gene expression profiling.

Promising results for prediction of outcome in breast cancer have been obtained by genome wide gene expression profiling. Some studies have suggested that an extensive overtreatment of breast cancer patients might be reduced by risk assessment with gene expression profiling. A patient group hardly examined in these studies is the low-risk patients for whom outcome is very difficult to predict with currently used methods. These patients do not receive adjuvant treatment according to the guidelines of the Danish Breast Cancer Cooperative Group (DBCG). In this study, 26 tumors from low-risk patients were examined with gene expression profiling. An intermediate risk group of 34 low-malignant T2 tumors that fulfilled all other low-risk criteria than tumor size was included to increase statistical power. A 32-gene classifier, HUMAC32, was identified and it predicted metastases with 80% sensitivity and 77% specificity. The classifier was also validated in an independent group of high-risk tumors resulting in comparable performance of HUMAC32 and a 70-gene classifier developed for this group. Furthermore, the 70-gene signature was tested in our low- and intermediate-risk samples. The results demonstrated high cross-platform consistency of the classifiers. Higher performance of HUMAC32 was demonstrated among the low-malignant cancers compared with the 70-gene classifier. This suggests that although the metastatic potential to some extend is determined by the same genes in groups of tumors with different characteristics and risk, expression-based classification specifically developed in low-risk patients have higher predictive power in this group.

Biomarkers, Tumor↗
PubMed2002

Etiology-specific gene expression profiles in rat mammary carcinomas.

Identification of etiology of human cancers is important for effective cancer prevention, and attempts to estimate the roles of a variety of environmental carcinogens in human cancers are being made. Here, we applied cDNA microarray technology to estimate whether gene expression profiles of cancers would reflect their etiology. Using rat mammary carcinoma models, expression profiles were analyzed in two groups of carcinomas induced by distinct carcinogens but with the same histological classification. Four carcinomas induced by 7,12-dimethylbenz[a]anthracene (DMBA) and three carcinomas induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and a high-fat diet were analyzed by a GeneChip oligonucleotide microarray that contained approximately 8000 rat genes. By hierarchical clustering analysis, the seven carcinomas were classified into two groups that exactly coincided with the DMBA-induced and the PhIP-induced groups. The correlation coefficient between the two groups was 0.63, and those between any carcinomas within each group ranged from 0.78 to 0.95. In addition, characteristic clusters of genes were also identified that highlighted distinct and common characteristics of both groups. Seventeen genes were down-regulated in the DMBA and up-regulated in the PhIP-induced groups. Thirty-three genes were regulated in the opposite manner. Our results indicated that gene expression profiles in cancers reflect their etiology and suggested a possibility that etiology of cancers could be retrospectively estimated from their expression profiles.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2005

Expression profiling reveals differences in metabolic gene expression between exercise-induced cardiac effects and maladaptive cardiac hypertrophy.

While cardiac hypertrophy elicited by pathological stimuli eventually leads to cardiac dysfunction, exercise-induced hypertrophy does not. This suggests that a beneficial hypertrophic phenotype exists. In search of an underlying molecular substrate we used microarray technology to identify cardiac gene expression in response to exercise. Rats exercised for seven weeks on a treadmill were characterized by invasive blood pressure measurements and echocardiography. RNA was isolated from the left ventricle and analysed on DNA microarrays containing 8740 genes. Selected genes were analysed by quantitative PCR. The exercise program resulted in cardiac hypertrophy without impaired cardiac function. Principal component analysis identified an exercise-induced change in gene expression that was distinct from the program observed in maladaptive hypertrophy. Statistical analysis identified 267 upregulated genes and 62 downregulated genes in response to exercise. Expression changes in genes encoding extracellular matrix proteins, cytoskeletal elements, signalling factors and ribosomal proteins mimicked changes previously described in maladaptive hypertrophy. Our most striking observation was that expression changes of genes involved in beta-oxidation of fatty acids and glucose metabolism differentiate adaptive from maladaptive hypertrophy. Direct comparison to maladaptive hypertrophy was enabled by quantitative PCR of key metabolic enzymes including uncoupling protein 2 (UCP2) and fatty acid translocase (CD36). DNA microarray analysis of gene expression changes in exercise-induced cardiac hypertrophy suggests that a set of genes involved in fatty acid and glucose metabolism could be fundamental to the beneficial phenotype of exercise-induced hypertrophy, as these changes are absent or reversed in maladaptive hypertrophy.

Animals↗
PubMed2002

Ascidian gene-expression profiles.

With the advent of gene-expression profiling, a large number of genes can now be investigated simultaneously during critical stages of development. This approach will be particularly informative in studies of ascidians, basal chordates whose genomes and embryology are uniquely suited for mapping developmental gene networks.

Animals↗
PubMed1999

Gene expression profiles in HTLV-I-immortalized T cells: deregulated expression of genes involved in apoptosis regulation.

Human T-cell leukemia virus type I (HTLV-I) is the etiologic agent of adult T-cell leukemia, an acute and often fatal T-cell malignancy. A key step in HTLV-I-induced leukemigenesis is induction of abnormal T-cell growth and survival. Unlike antigen-stimulated T cells, which cease proliferation after a finite number of cell division, HTLV-I-infected T cells proliferate indefinitely (immortalized), thus facilitating occurrence of secondary genetic changes leading to malignant transformation. To explore the molecular basis of HTLV-I-induced abnormal T-cell survival, we compared the gene expression profiles of normal and HTLV-I-immortalized T cells using 'gene array'. These studies revealed a strikingly altered expression pattern of a large number of genes along with HTLV-I-mediated T-cell immortalization. Interestingly, many of these deregulated genes are involved in the control of programmed cell death or apoptosis. These findings indicate that disruption of the cellular apoptosis-regulatory network may play a role in the HTLV-I-mediated oncogenesis.

Apoptosis↗
PubMed2006

The role of gene expression profiling in the clinical management of ovarian cancer.

Several studies have addressed the clinical value of gene expression profiling in the field of ovarian cancer. This paper reviews the current status of knowledge that can be derived from such studies. Gene expression profiles can be used to reveal sets of genes that can distinguish normal ovarian tissue from invasive ovarian carcinomas. Independent validation of these sets may result in the identification of (a set of) markers valuable for the detection in an early stage. Microarray analysis has shown that different histological subtypes of ovarian cancer might be partly reflected by a different aetiology through the deregulation and activation of different pathways. In addition, this heterogeneity could therefore also lead to different tumour behaviours. Worldwide, the combination of paclitaxel and platinum chemotherapy has been incorporated in the standard protocol for the management of patients with advanced stage ovarian cancer, although the outcome in individual patients is uncertain. Gene expression profiling was found to be a prognostic tool with respect to chemosensitivity and had a predictive performance of 78-86%. With increasing numbers of data from published reports, access to these data for the reproducibility of its results and pooling becomes more and more important and will possibly lead to more individualisation of therapy.

Female↗
PubMed2006

Monitoring expression profiles of Arabidopsis genes during cold acclimation and deacclimation using DNA microarrays.

A comparative analysis of gene expression profiles during cold acclimation and deacclimation is necessary to elucidate the molecular mechanisms of cold stress responses in higher plants. We analyzed gene expression profiles in the process of cold acclimation and deacclimation (recovery from cold stress) using two microarray systems, the 7K RAFL cDNA microarray and the Agilent 22K oligonucleotide array. By both microarray analyses, we identified 292 genes up-regulated and 320 genes down-regulated during deacclimation, and 445 cold up-regulated genes and 341 cold down-regulated genes during cold acclimation. Many genes up-regulated during deacclimation were found to be down-regulated during cold acclimation, and vice versa. The genes up-regulated during deacclimation were classified into (1) regulatory proteins involved in further regulation of signal transduction and gene expression and (2) functional proteins involved in the recovery process from cold-stress-induced damages and plant growth. We also applied expression profiling studies to identify the key genes involved in the biosynthesis of carbohydrates and amino acids that are known to play important roles in cold acclimation. We compared genes that are regulated during deacclimation with those regulated during rehydration after dehydration to discuss the similarity and difference of each recovery process.

Acclimatization↗
PubMed2003

Acute leukemia: subtype discovery and prediction of outcome by gene expression profiling.

Contemporary treatment of acute leukemia requires the accurate assignment of patients at diagnosis to specific risk groups. To determine whether gene expression profiling could enhance risk assignment, we used oligonucleotide microarrays to analyze the pattern of genes expressed in leukemic blasts from 360 pediatric ALL patients and 130 pediatric AML patients. Our analysis demonstrates that the single platform of gene expression profiling can accurately identify the known prognostically important genetic subtypes of ALL, including T-ALL, E2A-PBX1, TEL-AML1, MLL rearrangements, BCR-abl, and hyperdiploid >50 chromosomes, and AML, including t(15;17)[PML-RARalpha], t(8;21)[AML1-ETO], inv(16)[CBFbeta-MYH11], MLL gene rearrangement, and cases with FAB-M7 morphology. In addition, within ALL, a novel subgroup was identified based on its unique expression profile. Examination of the gene expression signatures for the different genetic subtypes of acute leukemia provided important insights into the molecular pathology of these leukemias.

Acute Disease↗
PubMed2005

Gene expression profiles correlate with the morphology and metastasis characteristics of renal cell carcinoma cells.

Renal cell carcinoma (RCC) shows various clinical behaviors, and currently surgical modalities are the only effective therapy against this cancer. To discern the genomic background affecting clinical characteristics such as metastasis, we analyzed the gene expression profiles of the RCCs by DNA microarray using cell lines originating from primary or metastatic lesions. RNA was extracted from ten SKRC RCC cell lines and gene expression profiling was performed using a cDNA microarray of nearly 4,000 human cDNA clones. We compared the gene expression profiles between these SKRC cell lines and the normal renal proximal tubular cell line and among SKRC cell lines that showed different characteristics. The clustering of the selected 62 genes revealed similar profiling patterns between SKRC-17 and SKRC-29 cells that were derived from metastatic RCC lesions. Another cell line from a metastatic lesion, SKRC-52, with a unique spindle-shaped morphology, had a different pattern of expression profiling from the other cell lines. We found several genes up-regulated in the cell lines from metastatic lesions; transgelin, which is reportedly involved in cell proliferation and migration, was up-regulated in SKRC-52. The unique profiling pattern of gene expression clearly correlated with cell morphology and metastatic potential. Such profiling might contribute to identifying the genes involved in the clinical characteristics of RCC.

Carcinoma, Renal Cell↗
PubMed2005

A microarray-based comparative analysis of gene expression profiles during grain development in transgenic and wild type wheat.

Global, comparative gene expression analysis is potentially a very powerful tool in the safety assessment of transgenic plants since it allows for the detection of differences in gene expression patterns between a transgenic line and the mother variety. In the present study, we compared the gene expression profile in developing seeds of wild type wheat and wheat transformed for endosperm-specific expression of an Aspergillus fumigatus phytase. High-level expression of the phytase gene was ensured by codon modification towards the prevalent codon usage of wheat genes and by using the wheat 1DX5HMW glutenin promoter for driving transgene expression. A 9K wheat unigene cDNA microarray was produced from cDNA libraries prepared mainly from developing wheat seed. The arrays were hybridised to flourescently labelled cDNA prepared from developing seeds of the transgenic wheat line and the mother variety, Bobwhite, at three developmental stages. Comparisons and statistical analyses of the gene expression profiles of the transgenic line vs. that of the mother line revealed only slight differences at the three developmental stages. In the few cases where differential expression was indicated by the statistical analysis it was primarily genes that were strongly expressed over a shorter interval of seed development such as genes encoding storage proteins. Accordingly, we interpret these differences in gene expression levels to result from minor asynchrony in seed development between the transgenic line and the mother line. In support of this, real time PCR validation of results from selected genes at the late developmental stage could not confirm differential expression of these genes. We conclude that the expression of the codon-modified A. fumigatus phytase gene in the wheat seed had no significant effects on the overall gene expression patterns in the developing seed.

6-Phytase↗
PubMed2005

Alteration in gene expression profile by full-length hepatitis B virus genome.

Persistent expression of hepatitis B virus (HBV) proteins is thought to be involved in virus-related hepatocarcinogenesis. Here, we compared the gene expression profile of cells persistently expressing the full-length HBV with that of negative control cells to comprehensively investigate virus-mediated changes in the gene expression of the host cells. RNA samples from both virus-expressing and negative control cells were used for the DNA array assay. DNA array assay and subsequent corroboration assays revealed that expression of 14 of 1,176 genes (1.2%) was altered in response to virus expression. The upregulated genes included CD44, high mobility group protein-I, thymosin beta-10 and 27-kD heat shock protein, while the downregulated genes included NM23-H1, all of which are thought to be associated with the development or progression of carcinoma in the liver or other organs. Furthermore, virus expression resulted in the decrease of two apoptosis-inducing molecules, caspase-3 and BAX, which may also contribute to carcinogenesis through prolonged survival of the host cell. Thus, expression of the virus genome caused carcinogenesis-related changes in host cell gene expression. HBV expression may change the host cell to a malignant phenotype through alterations in the expression levels of a set of genes.

Blotting, Western↗
PubMed2004

Gene expression profiling of epithelial ovarian tumours correlated with malignant potential.

BACKGROUND: Epithelial ovarian tumours exhibit a range of malignant potential, presenting distinct clinical phenotypes. Improved knowledge of gene expression changes and functional pathways associated with these clinical phenotypes may lead to new treatment targets, markers for early detection and a better understanding of disease progression. RESULTS: Gene expression profiling (Affymetrix, U95Av2) was carried out on 18 ovarian tumours including benign adenomas, borderline adenocarcinomas of low malignant potential and malignant adenocarcinomas. Clustering the expression profiles of samples from patients not treated with chemotherapy prior to surgery effectively classified 92% of samples into their proper histopathological group. Some cancer samples from patients treated with chemotherapy prior to surgery clustered with the benign adenomas. Chemotherapy patients whose tumours exhibited benign-like expression patterns remained disease free for the duration of this study as indicated by continued normal serum CA-125 levels. Statistical analysis identified 163 differentially expressed genes: 61 genes under-expressed in cancer and 102 genes over-expressed in cancer. Profiling the functional categories of co-ordinately expressed genes within this list revealed significant correlation between increased malignant potential and loss of both IGF binding proteins and cell adhesion molecules. Interestingly, in several instances co-ordinately expressed genes sharing biological function also shared chromosomal location. CONCLUSION: Our findings indicate that gene expression profiling can reliably distinguish between benign and malignant ovarian tumours. Expression profiles of samples from patients pre-treated with chemotherapy may be useful in predicting disease free survival and the likelihood of recurrence. Loss of expression of IGF binding proteins as well as specific cell adhesion molecules may be a significant mechanism of disease progression in ovarian cancer. Expression levels in borderline tumours were intermediate between benign adenomas and malignant adenocarcinomas for a significant portion of the differentially expressed genes, suggesting that borderline tumours are a transitional state between benign and malignant tumours. Finally, genes displaying coordinated changes in gene expression were often genetically linked, suggesting that changes in expression for these genes are the consequence of regional duplications, deletions or epigenetic events.

Cluster Analysis↗