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Regulação da expressão gênica pelo fosfato no fungo filamentoso Neurospora crassa; Regulation of Gene Expression by Phosphate in the Filamentous Fungus Neurospora crassa

Gras, Diana Ester
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/02/2009 Português
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75.86%
A regulação da expressão gênica é vital para todos os organismos se adaptarem rapidamente às mudanças ambientais. Estes mecanismos adaptativos são altamente complexos e a maioria deles não está completamente esclarecida. O fosfato inorgânico (Pi), um nutriente essencial para todos os organismos, é requerido em importantes processos celulares como a biosíntese de ácidos nucléicos e a sinalização metabólica. O sistema de aquisição de Pi no fungo filamentoso Neurospora crassa inclui pelo menos quatro genes regulatórios: nuc-2, preg, pgov e nuc-1. Em condições limitantes de Pi, NUC- 2, uma proteína com domínio de repetição de anquirina, inibe o funcionamento do complexo PREG-PGOV, ativando assim o fator de transcrição NUC-1 e a expressão de genes envolvidos na captação de fosfato, como fosfatases, fosfato permeases e nucleases. Visando entender a funcionalidade do gene nuc-2 na regulação da expressão gênica em resposta aos níveis de Pi exógeno, foram construídas duas bibliotecas de subtração de cDNA entre as linhagens selvagem St.L.74A e nuc-2A de N. crassa, cultivadas em Pilimitante. Obtivemos 52 transcritos induzidos e 16 reprimidos pela proteína NUC-2. A categorização funcional destas sequências revelou genes envolvidos em diversos processos celulares...

Regulação da expressão gênica pela toxina da aranha Phoneutria nigriventer no corpo cavernoso in vivo; In vivo regulation of gene expression in the corpus cavernosum by the Phoneutria nigriventer toxin

Villanova, Fabiola Elizabeth
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/09/2009 Português
Relevância na Pesquisa
75.76%
INTRODUÇÃO: O aracnídeo Phoneutria nigriventer, também conhecido por aranha-armadeira, possui um veneno complexo, contendo vários peptídeos que ativam canais iônicos nas células. Dentre estes, só dois neuropeptídeos, Tx2-5 e Tx2-6, destacam-se por relaxar o músculo liso trabecular do corpo cavernoso, induzindo ereção peniana em camundongos e ratos. Este efeito tem sido associado à produção de oxido nítrico pela ativação de óxido nítrico sintases. No entanto, faltam estudos mais amplos para determinar o papel de Tx2-6 na indução da ereção. OBJETIVOS: Identificar os genes diferencialmente expressos no tecido erétil de camundongos após indução da ereção pela Tx2-6 utilizando microarranjos de oligonucleotídeos. Validação dos resultados obtidos nos microarranjos por PCR quantitativa e imuno-histoquímica. MATERIAIS E MÉTODOS: Camundongos machos e adultos da linhagem Swiss foram divididos em dois grupos: controle (n=10), inoculados pela via intracavernosa com 20 l de solução salina; e tratado (n=10), os quais receberam 0,006gg/animal do peptídeo Tx2-6 diluído em 20 l de salina pela via intracavernosa. Uma hora após o início da ereção no grupo tratado todos os animais foram sacrificados e retirou-se o pênis. Este último foi dividido em dois fragmentos...

Spatial and temporal profiles for anti-inflammatory gene expression in leukocytes during a resolving model of peritonitis

Damazo, Amilcar S.; Yona, Simon; Flower, Roderick J.; Perretti, Mauro; Oliani, Sonia M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 4410-4418
Português
Relevância na Pesquisa
75.79%
The recent appreciation of the role played by endogenous counterregulatory mechanisms in controlling the outcome of the host inflammatory response requires specific analysis of their spatial and temporal profiles. In this study, we have focused on the glucocorticoid-regulated anti-inflammatory mediator annexin 1. Induction of peritonitis in wild-type mice rapidly (4 h) produced the expected signs of inflammation, including marked activation of resident cells (e.g., mast cells), migration of blood-borne leukocytes, mirrored by blood neutrophilia. These changes subsided after 48-96 h. In annexin 1null mice, the peritonitis response was exaggerated (∼40% at 4 h), with increased granulocyte migration and cytokine production. In blood leukocytes, annexin 1 gene expression was activated at 4, but not 24, h postzymosan, whereas protein levels were increased ai both time points. Locally, endothelial and mast cell annexin 1 gene expression was not detectable in basal conditions, whereas it was switched on during the inflammatory response. The significance of annexin 1 system plasticity in the anti-inflammatory properties of dexamethasone was assessed. Clear induction of annexin 1 gene in response to dexamethasone treatment was evident in the circulating and migrated leukocytes...

Tamoxifen inhibits transforming growth factor-α gene expression in human breast carcinoma samples treated with triiodothyronine

Conde, S. J.; Luvizotto, R. A M; Sibio, M. T.; Katayama, M. L H; Brentani, M. M.; Nogueira, C. R.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1047-1051
Português
Relevância na Pesquisa
75.81%
Objectives: To examine the effects of triiodothyronine (T3), 17β-estradiol (E2), and tamoxifen (TAM) on transforming growth factor (TGF)-α gene expression in primary breast cancer cell cultures and interactions between the different treatments. Methods and results: Patients included in the study (no.=12) had been newly diagnosed with breast cancer. Fresh human breast carcinoma tissue was cut into 0.3-mm slices. These slices were placed in six 35-mm dishes on 2-ml organ culture medium. Dishes received the following treatments: dish 1: ethanol; dish 2: T3; dish 3: T3+TAM; dish 4: TAM; dish 5: E2; dish 6: E2+TAM. TGF-α mRNA content was normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA levels. All tissues included in this study were positive for estrogen receptor (ER) and thyroid hormone receptor expression. Treatment with T3 for 48 h significantly increased TGF-α mRNA levels compared to controls (15-fold), and concomitant treatment with TAM reduced expression to 3.4-fold compared to controls. When only TAM was added to the culture medium, TGF-α mRNA expression increased 5.3-fold, significantly higher than with all other treatment modalities. Conclusion: We demonstrate that TGF-α mRNA expression is more efficiently upregulated by T3 than E2. Concomitant treatment with TAM had a mitigating effect on the T3 effect...

Homeobox gene expression profile indicates HOXA5 as a candidate prognostic marker in oral squamous cell carcinoma

Rodini, Camila Oliveira; Xavier, Flávia Caló Aquino; Paiva, Katiúcia Batista Silva; Destro, Maria Fernanda de Souza Setúbal; Moyses, Raquel Ajub; Michaluarte, Pedro; Carvalho, Marcos Brasilino; Fukuyama, Erica Erina; Tajara, Eloiza Helena; Okamoto, Os
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1180-1188
Português
Relevância na Pesquisa
75.84%
The search for molecular markers to improve diagnosis, individualize treatment and predict behavior of tumors has been the focus of several studies. This study aimed to analyze homeobox gene expression profile in oral squamous cell carcinoma (OSCC) as well as to investigate whether some of these genes are relevant molecular markers of prognosis and/or tumor aggressiveness. Homeobox gene expression levels were assessed by microarrays and qRT-PCR in OSCC tissues and adjacent non-cancerous matched tissues (margin), as well as in OSCC cell lines. Analysis of microarray data revealed the expression of 147 homeobox genes, including one set of six at least 2-fold up-regulated, and another set of 34 at least 2-fold down-regulated homeobox genes in OSCC. After qRT-PCR assays, the three most up-regulated homeobox genes (HOXA5, HOXD10 and HOXD11) revealed higher and statistically significant expression levels in OSCC samples when compared to margins. Patients presenting lower expression of HOXA5 had poorer prognosis compared to those with higher expression (P=0.03). Additionally, the status of HOXA5, HOXD10 and HOXD11 expression levels in OSCC cell lines also showed a significant up-regulation when compared to normal oral keratinocytes. Results confirm the presence of three significantly upregulated (>4-fold) homeobox genes (HOXA5...

Experimental hyperthyroidism decreases gene expression and serum levels of adipokines in obesity

Luvizotto, Renata de Azevedo Melo; Nascimento, André Ferreira Do; Síbio, Maria Teresa De; Olímpio, Regiane Marques Castro; Conde, Sandro José; Lima-Leopoldo, Ana Paula; Leopoldo, André Soares; Cicogna, Antonio Carlos; Nogueira, Célia Regina
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
75.8%
Aims. To analyze the influence of hyperthyroidism on the gene expression and serum concentration of leptin, resistin, and adiponectin in obese animals. Main Methods. Male Wistar rats were randomly divided into two groups: control (C)fed with commercial chow ad libitumand obese (OB)fed with a hypercaloric diet. After group characterization, the OB rats continued receiving a hypercaloric diet and were randomized into two groups: obese animals (OB) and obese with 25g triiodothyronine (T3)/100BW (OT). The T3 dose was administered every day for the last 2 weeks of the study. After 30 weeks the animals were euthanized. Samples of blood and adipose tissue were collected for biochemical and hormonal analyses as well as gene expression of leptin, resistin, and adiponectin. Results. T3 treatment was effective, increasing fT3 levels and decreasing fT4 and TSH serum concentration. Administration of T3 promotes weight loss, decreases all fat deposits, and diminishes serum levels of leptin, resistin, and adiponectin by reducing their gene expression. Conclusions. Our results suggest that T3 modulate serum and gene expression levels of leptin, resistin, and adiponectin in experimental model of obesity, providing new insights regarding the relationship between T3 and adipokines in obesity. Copyright © 2012 Renata de Azevedo Melo Luvizotto et al.

Maternal protein restriction during pregnancy affects gene expression and immunolocalization of intestinal nutrient transporters in rats

Pinheiro, Daniela F.; Pinheiro, Patricia F.F.; Buratini, José; Castilho, Anthony C.S.; Lima, Paula F.; Trinca, Luiza A.; Vicentini-Paulino, Maria de Lourdes M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 281-289
Português
Relevância na Pesquisa
75.76%
Intrauterine dietary restriction may cause changes in the functioning of offspring organs and systems later in life, an effect known as fetal programming. The present study evaluated mRNA abundance and immunolocalization of nutrient transporters as well as enterocytes proliferation in the proximal, median and distal segments of small intestine of rats born to protein-restricted dams. Pregnant rats were fed hypoproteic (6% protein) or control (17% protein) diets, and offspring rats were evaluated at 3 and 16 weeks of age. The presence of SGLT1 (sodium-glucose co-transporter 1), GLUT2 (glucose transporter 2), PEPT1 (peptide transporter 1) and the intestinal proliferation were evaluated by immunohistochemical techniques and the abundance of specific mRNA for SGLT1, GLUT2 and PEPT1 was assessed by the real-time PCR technique. Rats born to protein-restricted dams showed higher cell proliferation in all intestinal segments and higher gene expression of SGLT1 and PEPT1 in the duodenum. Moreover, in adult animals born to protein-restricted dams the immunoreactivity of SGLT1, GLUT2 and PEPT1in the duodenum was more intense than in control rats. Taken together, the results indicate that changes in the small intestine observed in adulthood can be programmed during the gestation. In addition...

Papel do sistema AI-3/epinefrina/norepinefrina na regulação da expressão gênica de Escherichia coli enteropatogênica atípica; Role of AI-3/epinephrine/norepinephrine system in atypical enteropathogenic Escherichia coli gene expression

Fernanda Maria Franzin
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/12/2013 Português
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75.92%
Escherichia coli enteropatogênica atípica (aEPEC) faz parte de um grupo de patógenos capazes de formar um tipo de lesão em células epiteliais denominada Attaching and Effacing (A/E). Os genes requeridos para a formação da lesão A/E estão localizados em uma ilha de patogenicidade denominada Locus of Enterocyte Effacement (LEE). A regulação da expressão dos genes de LEE é um processo complexo e envolve inúmeros fatores e vias regulatórias, incluindo o sistema de quorum sensing AI- 3/Epinefrina/Norepinefrina. O sensor histidina-quinase QseC é responsável por detectar AI-3 produzido por outras bactérias e epinefrina/norepinefrina produzidas pelo hospedeiro e iniciar uma cascata regulatória que induz a expressão de genes de virulência. Para avaliar o papel desse sistema na regulação de fatores de virulência de aEPEC, um mutante para o gene qseC foi gerado e analisado a nível transcricional e fenotípico quanto a sua motilidade, capacidade de secretar proteínas e induzir lesão A/E, na presença e/ou ausência do sinal epinefrina. Ensaios de qRT-PCR demonstraram níveis transcricionais diminuídos para LEE e para os genes flhD, fliC e nleA no mutante, sugerindo que QseC regula a expressão desses fatores de virulência. Ensaios de motilidade...

Gene expression regulation and lineage evolution: the North and South tale of the hybrid polyploid Squalius alburnoides complex

Pala, Irene; Schartl, Manfred; Brito, Miguel; Malta-Vacas, Joana; Coelho, Maria Manuela
Fonte: Royal Society Publishing Publicador: Royal Society Publishing
Tipo: Artigo de Revista Científica
Publicado em /11/2010 Português
Relevância na Pesquisa
85.79%
The evolution of hybrid polyploid vertebrates, their viability and their perpetuation over evolutionary time have always been questions of great interest. However, little is known about the impact of hybridization and polyploidization on the regulatory networks that guarantee the appropriate quantitative and qualitative gene expression programme. The Squalius alburnoides complex of hybrid fish is an attractive system to address these questions, as it includes a wide variety of diploid and polyploid forms, and intricate systems of genetic exchange. Through the study of genome-specific allele expression of seven housekeeping and tissue-specific genes, we found that a gene copy silencing mechanism of dosage compensation exists throughout the distribution range of the complex. Here we show that the allele-specific patterns of silencing vary within the complex, according to the geographical origin and the type of genome involved in the hybridization process. In southern populations, triploids of S. alburnoides show an overall tendency for silencing the allele from the minority genome, while northern population polyploids exhibit preferential biallelic gene expression patterns, irrespective of genomic composition. The present findings further suggest that gene copy silencing and variable expression of specific allele combinations may be important processes in vertebrate polyploid evolution.

The ontogeny of hepatic growth hormone receptor and insulin-like growth factor I gene expression in the sheep fetus during late gestation: developmental regulation by cortisol

Li, J.; Owens, J.; Owens, P.; Saunders, J.; Fowden, A.; Gilmour, R.
Fonte: ENDOCRINE SOC Publicador: ENDOCRINE SOC
Tipo: Artigo de Revista Científica
Publicado em //1996 Português
Relevância na Pesquisa
75.8%
The effects of cortisol on hepatic GH receptor and insulin-like growth factor-I (IGF-I) gene expression were investigated in sheep fetuses during late gestation and after experimental manipulation of plasma cortisol levels by fetal adrenalectomy and exogenous infusion of cortisol. Hepatic GH receptor and IGF-I messenger RNA (mRNA) levels increased with increasing gestational age in parallel with the normal rise in fetal cortisol levels toward term (145 +/- 2 days). These increases in mRNA abundance toward term were prevented when the prepartum cortisol surge was abolished by fetal adrenalectomy and were stimulated prematurely in fetuses younger than 130 days by exogenous infusion of cortisol. Both the class 1 and class 2 transcripts of the IGF-I gene were increased when cortisol levels were elevated either endogenously or exogenously. However, there were no significant changes in fetal plasma IGF-I levels either with increasing gestational age or in response to experimental manipulation of the fetal cortisol level. When the data from all the fetuses were combined irrespective of treatment or gestational age, there were significant positive correlations between the log plasma cortisol concentration in utero and the abundance of GH receptor and IGF-I mRNA in the fetal liver. There was also a significant inverse relationship between log plasma cortisol and the ratio of class 1 to class 2 transcript abundance in the fetal liver. These findings show that cortisol is a physiological regulator of hepatic GH receptor and IGF-I gene expression in fetal sheep during late gestation and indicate that it preferentially increases the class 2 transcript of the IGF-I gene. The prepartum cortisol surge therefore appears to have an important maturational role in initiating the perinatal switch from the fetal to adult modes of somatotrophic regulation.

Ex vivo early embryo development and effects on gene expression and imprinting

Gardner, D.; Lane, M.
Fonte: C S I R O Publishing Publicador: C S I R O Publishing
Tipo: Artigo de Revista Científica
Publicado em //2005 Português
Relevância na Pesquisa
75.72%
The environment to which the mammalian embryo is exposed during the preimplantation period of development has a profound effect on the physiology and viability of the conceptus. It has been demonstrated that conditions that alter gene expression, and in some instances the imprinting status of specific genes, have all previously been shown to adversely affect cell physiology. Thus, questions are raised regarding the aetiology of abnormal gene expression and altered imprinting patterns, and whether problems can be averted by using more physiological culture conditions. It is also of note that the sensitivity of the embryo to its surroundings decreases as development proceeds. Post compaction, environmental conditions have a lesser effect on gene function. This, therefore, has implications regarding the conditions used for IVF and the culture of the cleavage stage embryo. The developmental competence of the oocyte also impacts gene expression in the embryo, and therefore superovulation has been implicated in abnormal methylation and imprinting in the resultant embryo. Furthermore, the genetics and dietary status of the mother have a profound impact on embryo development and gene expression. The significance of specific animal models for human assisted reproductive technologies (ART) is questioned...

Cytokine regulation of syndecan-1 and -2 gene expression in human periodontal fibroblasts and osteoblasts

Worapamorn, W.; Tam, S.; Li, H.; Haase, H.; Bartold, P.
Fonte: Munksgaard Int Publ Ltd Publicador: Munksgaard Int Publ Ltd
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
Relevância na Pesquisa
75.79%
Cell-surface proteoglycans participate in several biological functions including interactions with a variety of growth factors and cytokines. Regulation of syndecan-1 and -2 gene expression was investigated in human periodontal ligament fibroblasts (PDLF), osteoblasts (OB) and gingival fibroblasts (GF), in response to platelet-derived growth factor (PDGF-BB), transforming growth factor (TGF-beta 1), and interleukin (IL-1 beta) by Northern blot analyses. We also compared the effect of PDGF-BB and TGF-beta 1, separately and in combination, in the prolonged presence of IL-1 beta on the expression of both syndecan genes. The results demonstrated that the three cell lines regulated the expression of syndecan-1 and -2 in response to growth factors and cytokines in different manners. These cell lines increased syndecan-1 mRNA levels in response to either PDGF-BB or TGF-beta 1 and decreased levels in response to IL-1 beta. The effect of IL-1 beta on syndecan-1 mRNA synthesis was partially reversed after adding PDGF-BB and TGF-beta 1, separately or in combination, in the presence of IL-1 beta. In contrast, syndecan-2 mRNA level was markedly upregulated in response to either TGF-beta 1 or IL-1 beta in OB when compared with the other two cell lines. However...

Impact of glucose infusion on the structural and functional characteristics of adipose tissue and on hypothalamic gene expression for appetite regulatory neuropeptides in the sheep fetus during late gestation

Muhlhausler, B.; Adam, C.; Marrocco, E.; Findlay, P.; Roberts, C.; McFarlane, J.; Kauter, K.; McMillen, I.
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Publicado em //2005 Português
Relevância na Pesquisa
75.77%
In the present study, our aim was to determine whether intrafetal glucose infusion increases fetal adiposity, synthesis and secretion of leptin and regulates gene expression of the ‘appetite regulatory’ neuropeptides neuropepetide Y (NPY), agouti-related peptide (AGRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) and receptors (leptin receptor (OB-Rb) and melancortin 3 receptor (MC3R)) within the fetal hypothalamus. Glucose (50% dextrose in saline) or saline was infused (7.5 ml h−1) into fetal sheep between 130 and 140 days gestation (term = 150 ± 3 days gestation). Glucose infusion increased circulating glucose and insulin concentrations, mean lipid locule size (532.8 ± 3.3 μm2versus 456.7 ± 14.8 μm2) and total unilocular fat mass (11.7 ± 0.6 g versus 8.9 ± 0.6 g) of the perirenal fat depot. The expression of OB-Rb mRNA was higher in the ventromedial nucleus compared to the arcuate nucleus of the hypothalamus in both glucose and saline infused fetuses (F= 8.04; P < 0.01) and there was a positive correlation between expression of OB-Rb and MC3R mRNA in the arcuate nucleus (r= 0.81; P < 0.005). Glucose infusion increased mRNA expression for POMC, but not for the anorectic neuropeptide CART...

Gene expression analysis of multiple gastrointestinal regions reveals activation of common cell regulatory pathways following cytotoxic chemotherapy

Bowen, J.; Gibson, R.; Tsykin, A.; Stringer, A.; Logan, R.; Keefe, D.
Fonte: Wiley-liss Publicador: Wiley-liss
Tipo: Artigo de Revista Científica
Publicado em //2007 Português
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75.78%
Gastrointestinal mucositis involves many changes at the gene level, affecting epithelial/subepithelial interactions and leading to overt damage. The regional specificity and time course of these changes, and how they relate to subsequent mucositis development however remain unknown. The aim of this study was to determine the early time course of gene expression changes along the gastrointestinal tract of the DA rat following chemotherapy. Female DA rats were treated with a single dose of 200 mg/kg irinotecan to induce mucositis, and were killed at short intervals following treatment. Small sections of stomach, jejunum and colon were harvested for analysis of genetic profiles. RNA was hybridised to high density Affymetrix oligonucleotide microarrays. Data analysis was carried out with software package, TimeCourse, freely available through Bioconductor. As early as 1 hr following chemotherapy, expression of hundreds of genes was altered, including those for transcription factors, stress response proteins and protein turnover. These genes are involved in cell proliferation, differentiation and apoptosis along with other cellular processes. At early time points, there was a significant response involving the mitogen-activated protein kinase pathway...

Regulation of gene expression in bovine Blastocysts in response to oxygen and the iron chelator desferrioxamine

Harvey, A.; Kind, K.; Thompson, J.
Fonte: Soc Study Reproduction Publicador: Soc Study Reproduction
Tipo: Artigo de Revista Científica
Publicado em //2007 Português
Relevância na Pesquisa
75.9%
Low (2%) oxygen conditions during postcompaction culture of bovine blastocysts improve embryo quality and are associated with small increases in the expression of glucose transporter 1 (SLC2A1), anaphase promoting complex (ANAPC1), and myotrophin (MTPN), suggesting a role for oxygen in the regulation of embryo development, mediated through oxygen-sensitive gene expression. However, bovine embryos, to at least the blastocyst stage, lack detectable levels of the key regulator of oxygen-sensitive gene expression, hypoxia-inducible 1 alpha (HIF1A), while the less well-characterized HIF2 alpha protein is readily detectable. Here we report that other key HIF1 regulated genes are not significantly altered in their expression pattern in bovine blastocysts in response to reduced oxygen concentrations postcompaction-with the exception of lactate dehydrogenase A (LDHA), which was significantly increased following 2% oxygen culture. Antioxidant enzymes have been suggested as potential HIF2 target genes, but their expression was not altered following low-oxygen culture in the bovine blastocyst. The addition of desferrioxamine (an iron chelator and inducer of HIF-regulated gene expression) during postcompaction stages significantly increased SLC2A1...

Protein arginine methyltransferase 6-dependent gene expression and splicing: association with breast cancer outcomes

Dowhan, D.; Harrison, M.; Eriksson, N.; Bailey, P.; Pearen, M.; Fuller, P.; Funder, J.; Simpson, E.; Leedman, P.; Tilley, W.; Brown, M.; Clarke, C.; Muscat, G.
Fonte: Soc Endocrinology Publicador: Soc Endocrinology
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
Relevância na Pesquisa
75.8%
Protein arginine methyltransferase-6 (PRMT6) regulates steroid-dependent transcription and alternative splicing and is implicated in endocrine system development and function, cell death, cell cycle, gene expression and cancer. Despite its role in these processes, little is known about its function and cellular targets in breast cancer. To identify novel gene targets regulated by PRMT6 in breast cancer cells, we used a combination of small interfering RNA and exon-specific microarray profiling in vitro coupled to in vivo validation in normal breast and primary human breast tumours. This approach, which allows the examination of genome-wide changes in individual exon usage and total transcript levels, demonstrated that PRMT6 knockdown significantly affected i) the transcription of 159 genes and ii) alternate splicing of 449 genes. The PRMT6-dependent transcriptional and alternative splicing targets identified in vitro were validated in human breast tumours. Using the list of genes differentially expressed between normal and PRMT6 knockdown cells, we generated a PRMT6-dependent gene expression signature that provides an indication of PRMT6 dysfunction in breast cancer cells. Interrogation of several well-studied breast cancer microarray expression datasets with the PRMT6 gene expression signature demonstrated that PRMT6 dysfunction is associated with better overall relapse-free and distant metastasis-free survival in the oestrogen receptor (ER (ESR1)) breast cancer subgroup. These results suggest that dysregulation of PRMT6-dependent transcription and alternative splicing may be involved in breast cancer pathophysiology and the molecular consequences identifying a unique and informative biomarker profile.; Dennis H. Dowhan...

Identification of an enhancer that increases miR-200b~200a~429 gene expression in breast cancer cells

Attema, J.; Bert, A.; Lim, Y.; Kolesnikoff, N.; Lawrence, D.; Pillman, K.; Smith, E.; Drew, P.; Khew-Goodall, Y.; Shannon, F.; Goodall, G.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
Relevância na Pesquisa
75.81%
The miR-200b~200a~429 gene cluster is a key regulator of EMT and cancer metastasis, however the transcription-based mechanisms controlling its expression during this process are not well understood. We have analyzed the miR-200b~200a~429 locus for epigenetic modifications in breast epithelial and mesenchymal cell lines using chromatin immunoprecipitation assays and DNA methylation analysis. We discovered a novel enhancer located approximately 5.1kb upstream of the miR-200b~200a~429 transcriptional start site. This region was associated with the active enhancer chromatin signature comprising H3K4me1, H3K27ac, RNA polymerase II and CpG dinucleotide hypomethylation. Luciferase reporter assays revealed the upstream enhancer stimulated the transcription of the miR-200b~200a~429 minimal promoter region approximately 27-fold in breast epithelial cells. Furthermore, we found that a region of the enhancer was transcribed, producing a short, GC-rich, mainly nuclear, non-polyadenylated RNA transcript designated miR-200b eRNA. Over-expression of miR-200b eRNA had little effect on miR-200b~200a~429 promoter activity and its production did not correlate with miR-200b~200a~429 gene expression. While additional investigations of miR-200b eRNA function will be necessary...

Genetic architecture of gene expression in the chicken

Stanley, D.; Watson-Haigh, N.; Cowled, C.; Moore, R.
Fonte: BioMed Central Ltd. Publicador: BioMed Central Ltd.
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
Relevância na Pesquisa
75.74%
BACKGROUND The annotation of many genomes is limited, with a large proportion of identified genes lacking functional assignments. The construction of gene co-expression networks is a powerful approach that presents a way of integrating information from diverse gene expression datasets into a unified analysis which allows inferences to be drawn about the role of previously uncharacterised genes. Using this approach, we generated a condition-free gene co-expression network for the chicken using data from 1,043 publically available Affymetrix GeneChip Chicken Genome Arrays. This data was generated from a diverse range of experiments, including different tissues and experimental conditions. Our aim was to identify gene co-expression modules and generate a tool to facilitate exploration of the functional chicken genome. RESULTS Fifteen modules, containing between 24 and 473 genes, were identified in the condition-free network. Most of the modules showed strong functional enrichment for particular Gene Ontology categories. However, a few showed no enrichment. Transcription factor binding site enrichment was also noted. CONCLUSIONS We have demonstrated that this chicken gene co-expression network is a useful tool in gene function prediction and the identification of putative novel transcription factors and binding sites. This work highlights the relevance of this methodology for functional prediction in poorly annotated genomes such as the chicken.; Dragana Stanley...

Estudo de regiões evolutivamente conservadas e de fatores de transcrição possivelmente envolvidos na regulação da expressão do gene da 'Miostatina' em vertebrados; Study of evolutionary conserved regions and transcription factors possibly involved in the regulation of the Myostatin gene expression in vertebrates

Carolina Stefano Mantovani
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/03/2015 Português
Relevância na Pesquisa
75.87%
A Miostatina (MSTN) é uma proteína que regula negativamente a formação de musculatura esquelética, e sua estrutura e função são conservadas em diversas espécies, incluindo humanos. O nocaute de seu gene causa hiperplasia e hipertrofia das fibras musculares, o que despertou grande interesse médico e agropecuário desde a descoberta deste gene. Trabalhos anteriores descrevem a função da proteína, mas ainda faltam dados sobre a regulação da sua expressão gênica. Recentemente, o promotor do gene da Mstn foi identificado e caracterizado pelo nosso grupo de pesquisa, a partir de uma abordagem filogenética. Entretanto, além do promotor, também existem outros elementos cis-reguladores que podem atuar como estimuladores ou silenciadores do processo de transcrição gênica. Em conjunto com o promotor gênico, esses elementos controlam a taxa de transcrição e conferem especificidade espacial e temporal para sua expressão. Sendo assim, a proposta deste trabalho foi identificar e caracterizar possíveis elementos cis-reguladores da Mstn a fim de ampliar o conhecimento sobre a sua regulação transcricional. Para tal, análises de genômica comparativa, semelhantes àquelas empregadas na identificação do promotor gênico da Mstn...

Genome-wide analysis of gene expression in T cells to identify targets of the NF-kappa B transcription factor c-Rel

Bunting, Karen; Rao, Sudha; Hardy, Kristine; Woltring, Donna; Denyer, Gareth; Wang, Jun; Gerondakis, Steve; Shannon, M Frances
Fonte: American Association of Immunologists Publicador: American Association of Immunologists
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
75.71%
It is well established that the NF-κB family of transcription factors serves a major role in controlling gene expression in response to T cell activation, but the genome-wide roles of individual family members remain to be determined. c-Rel, a member of