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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Intratumoral heterogeneity in early breast cancer

STOGIANNITSI, MARIA January 2020 (has links)
The use of adjuvant The use of adjuvant polychemotherapy (ACT) confers unequivocal benefits in terms of relapse free (RFS) and overall survival (OS) after resection of early breast cancer (BC). Although the magnitude of benefit is the same regardless of clinicopathological factors such as ER expression or nodal stage, it is clear that a substantial proportion of patients will eventually relapse and succumb to the disease. As a result, consistent efforts are made towards exploring biomarkers for prognostication, risk stratification and eventually for patient selection for novel therapies such as the modulation of the tumor-host response with the use of PD-1 inhibitors. Intratumoral heterogeneity (ITH) could be a potential driver of resistance to therapy and biologic aggressiveness. Cell-to-cell variability in tumors has been known for over a century, yet attempts to measure it and evaluate its clinical impact are just emerging. Heterogeneity both at the genetic and epigenetic level has been proposed to influence many aspects of tumor biology and clinical behavior, including resistance to pharmacologic therapies. In particular, the ongoing mutation rate continues the ITH of unselected clones, potentially increasing their fitness and thus becoming the driving force that promotes clonal expansion and phenotypic diversification. As a result, the delivery of precision medicine is complicated, possibly affecting patient outcomes. Quantifying the spatial ITH of the disease may result in the optimization of management algorithms. The main objective of this study is to demonstrate the analytical validity of RNAscope for the detection of ER, HER2 and PD-L1 expression in breast cancer tissue. The secondary objective is to study the spatial distribution between protein and gene expression of PD-L1 as determined through the use of immunofluorescence and RNAscope, respectively. polychemotherapy (ACT) confers unequivocal benefits in terms of relapse free (RFS) and overall survival (OS) after resection of early breast cancer (BC). Although the magnitude of benefit is the same regardless of clinicopathological factors such as ER expression or nodal stage, it is clear that a substantial proportion of patients will eventually relapse and succumb to the disease. As a result, consistent efforts are made towards exploring biomarkers for prognostication, risk stratification and eventually for patient selection for novel therapies such as the modulation of the tumor-host response with the use of PD-1 inhibitors. Intratumoral heterogeneity (ITH) could be a potential driver of resistance to therapy and biologic aggressiveness. Cell-to-cell variability in tumors has been known for over a century, yet attempts to measure it and evaluate its clinical impact are just emerging. Heterogeneity both at the genetic and epigenetic level has been proposed to influence many aspects of tumor biology and clinical behavior, including resistance to pharmacologic therapies. In particular, the ongoing mutation rate continues the ITH of unselected clones, potentially increasing their fitness and thus becoming the driving force that promotes clonal expansion and phenotypic diversification. As a result, the delivery of precision medicine is complicated, possibly affecting patient outcomes. Quantifying the spatial ITH of the disease may result in the optimization of management algorithms. The main objective of this study is to demonstrate the analytical validity of RNAscope for the detection of ER, HER2 and PD-L1 expression in breast cancer tissue. The secondary objective is to study the spatial distribution between protein and gene expression of PD-L1 as determined through the use of immunofluorescence and RNAscope, respectively.
112

Analysis of non-coding RNA expression in medium spiny neurons of Huntington disease model mice / ハンチントン病モデルマウスの中型有棘神経細胞におけるノンコーディングRNAの発現変化 / ハンチントンビョウ モデル マウス ノ チュウガタ ユウキョク シンケイ サイボウ ニオケル ノンコーディング RNA ノ ハツゲン ヘンカ

朴 洪宣, Hongsun Park 22 March 2019 (has links)
Huntington Disease (HD) is a neurodegenerative disorder caused by expanded CAG repeats in the exon1 of huntingtin gene (HTT). The mutant HTT affects the transcriptional profile of neurons by disrupting the activities of transcriptional machinery and alters expression of many genes. In this study, we identified dysregulated non-coding RNAs (ncRNAs) in medium spiny neurons of 4-week-old HD model mouse. Also, we observed the intracellular localizations of Abhd11os and Neat1 ncRNAs by ViewRNA in situ hybridization, which could provide more precise detection, suggesting that it is a useful method to investigate the expression changes of genes with low expression levels. / 博士(理学) / Doctor of Philosophy in Science / 同志社大学 / Doshisha University
113

Physical Mapping of Ribosomal Genes in New World Members of the Genus Chenopodium Using Fluorescence in Situ Hybridization

Sederberg, Maria C. 27 October 2008 (has links) (PDF)
The genus Chenopodium contains many economically important species in the New World, but is relatively understudied and poorly understood, especially in terms of evolutionary relationships. A better understanding of the structure of this genus could significantly help in breeding efforts on its cultivated members, notably the tetraploid C. quinoa and also certain varieties of C. berlandieri, also tetraploid. Of special concern is determining which diploid weed species are the most likely ancestors for C. quinoa, C. berlandieri, and the other tetraploid members of subsection Cellulata. The phylogeny can be understood in part by examining the ribosomal RNA loci and observing how many copies of the 5S and 45S loci each New World species contains. In this work, the 5S and 45S ribosomal RNA loci are characterized by means of fluorescence in situ hybridization in 23 Chenopodium species collected in the New World, with the 5S locus labeled red and the 45S locus labeled green. Based on these results, the pool of most likely candidate ancestor species for C. quinoa and C. berlandieri includes C. fremontii, C. incanum, C. neomexicanum, and C. watsonii.
114

REDOX POTENTIAL (ORP) REGULATION OF NUTRIENT REMOVAL IN WASTEWATER TREATMENT PROCESSES AND THE STRUCTURE - FUNCTION ANALYSIS OF ACTIVATED SLUDGE FLOC

LI, BAIKUN 22 May 2002 (has links)
No description available.
115

Humant papillomvirus som riskmarkör för utveckling av prolifererande verrukös leukoplaki

Gustavsson, Angelica, Hjalmarsson, Josefine January 2013 (has links)
Prolifererande verrukös leukoplaki, PVL, är en ovanlig sjukdom som yttrar sig genom multipla, vita förändringar i munslemhinnan som recidiverar och med tiden riskerar att utvecklas till cancer. Diagnosen kan endast ställas kliniskt när sjukdomsförloppet pågått under lång tid och det finns heller inga effektiva behandlingsmetoder. Etiologin till sjukdomen är okänd, men idag vet man att det finns ett samband mellan cancerutveckling och vissa virustyper.Syftet med studien är att undersöka om det går att påvisa humant papillom virus, HPV, i vävnadsprover från patienter som kan misstänkas ha PVL. Urvalet bestod av 11 patientfall, där vävnadsprover från biobanken vid avdelningen för oral patologi, Malmö högskola, samlats in och studerats med kromogen in situ hybridisering. Resultaten visade en högre förekomst av HPV i biopsier tagna i det senare skedet av sjukdomen jämfört med tidigare biopsier. En specifik HPV-genotyp kunde dock inte identifieras. I denna studie har det inte varit möjligt att påvisa HPV med in situ hybridisering, i ett tidigt staddium av PVL, som en möjlig indikator på sjukdomsutveckling. / Proliferative verrucous leukoplakia, PVL, is a rare disease that is characterized by multiple and recurrent white lesions in the oral epithelium which over time may develop into cancer. The diagnosis can only be made by the clinician when the disease has progressed for a long time. There is no effective treatment. The etiology of the disease is unknown but today it is known that there is a link between cancer and certain viruses.The purpose of this study is to investigate whether it is possible to detect human papilloma virus, HPV, in tissue samples from patients who possibly are affected by PVL.The selected samples consisted of 11 cases in which tissue samples from the biobank at the Department of Oral Pathology at Malmö University, were collected and HPV was detected by chromogenic in situ hybridization. The results showed a higher incidence of HPV in biopsies taken at a later stage of the disease compared with previous biopsies. However, a specific HPV genotype could not be identified.In this study, it has not been possible to demonstrate HPV with in situ hybridization at an early state of PVL as a putative indicator of disease development
116

Chromosome and Genome Evolution in Culicinae Mosquitoes

Masri, Reem Abed 14 July 2021 (has links)
The Culicinae is the most extensive subfamily among the Culicidae family of mosquitoes. Two genera, Culex and Aedes, from this subfamily have world-wide distribution and are responsible for transmitting of several deadly diseases including Zika, West Nile fevers, chikungunya, dengue, and Rift Valley fevers. Developing high-quality genome assembly for mosquitoes, studying their population structure, and evolution can help to facilitate the development of new strategies for vector control. Studies on Aedes albopitcus as well as on species from the Culex pipiens complex, which are widely spread in the United States, provide excellent models on these topics. Ae. albopictus is one of the most dangerous invasive mosquito species in the world that transmits more than 20 arboviruses. This species has highly repetitive genome that is the largest among mosquito genomes sequenced so far. Thus, sequencing and assembling of such genome is extremally challenging. As a result, the lack of high-quality Ae. albopictus genome assembly has delayed the progress in understanding its biology. To produce a high-quality genome assembly, it was important to anchor genomic scaffolds to the cytogenetic map creating a physical map of the genome assembly. We first developed a new gene-based approach for the physical mapping of repeat-rich mosquito genomes. The approach utilized PCR amplification of the DNA probes based on complementary DNA (cDNA) that does not include repetitive DNA sequences. This method was then used for the development of a physical map for Ae. albopictus based on the in situ hybridization of fifty cDNA fragments or gene exons from twenty-four scaffolds to the mitotic chromosomes from imaginal discs. This study resulted in the construction of a first physical map of the Ae. albopictus genome as well as mapping viral integration and polyphenol oxidase genes. Moreover, comparing our present Ae. albopictus physical map to the current Ae. aegypti assembly indicated the presence of multiple chromosomal inversions between them. To better understand population structure and chromosome evolution in Culicinae mosquitoes, especially in the Culex pipiens complex, we studied genomic and chromosomal differentiation between two subspecies Cx. pipiens pipiens and Cx. pipiens molestus. For the species responsible for the spread of human diseases, understanding the population dynamics and processes of taxa diversification is important for an effective mosquito control . Two vectors of West Nile virus, Cx. p. pipiens and Cx. p. molestus, exhibit epidemiologically important behavioral and physiological differences, but the whole-genome divergence between them was unexplored. The first goal of this study was to better understand the level of genomic differentiation and population structures of Cx. p. pipiens and Cx. p. molestus from different continents. We sequenced and compared whole genomes of 40 individual mosquitoes from two locations in Eurasia and two in North America. Principal Component, ADMIXTURE, and neighbor joining analyses of the nuclear genomes identified two major intercontinental, monophyletic clusters of Cx. p. pipiens and Cx. p. molestus. The level of genomic differentiation between the subspecies was uniform along chromosomes. The ADMIXTURE analysis determined signatures of admixture in Cx. p. pipens populations, but not in Cx. p. molestus populations. Thus, our study identified that Cx. p. molestus and Cx. p. pipiens represent different evolutionary units with monophyletic origin that have undergone incipient ecological speciation. The second goal was to study differences at the chromosome level between these two organisms. We first measured whole chromosome and chromosome arm length differences between Cx. p. molestus and Cx. p. pipiens as a basic cytogenetic approach. In addition, we used the novel Hi-C approach to detect chromosomal rearrangements between them since Hi-C was successful in detecting a known inversion in Cx. quinquefasciatus. Cx. p. molestus and Cx. p. pipiens embryos were used to perform the Hi-C technique. Analysis of the Hi-C data showed the presence of two different inversions in Cx. p. pipiens and Cx. p. molestus heatmap, which could explain their different physiology and adaptation in nature. Developing modern genomic and cytogenetic tools is important to enhance the quality of genome assemblies, improve gene annotation, and provide a better framework for comparative and population genomics of mosquitoes; also it is the foundation for the development of novel genome-based approaches for vector control. / Doctor of Philosophy / Mosquitoes are medically important insects because they vector a range of diseases that infect humans. The subfamily Culicinae is responsible for transmitting such diseases as Zika, dengue, and West Nile fevers, which have triggered fatal infections and epidemics in multiple parts of the world. Since 2010-2016, studies have reported exceeding levels of insecticide resistance that slows the disease elimination process. Novel transgenic techniques have a tremendous potential for more efficiently minimizing mosquito-borne diseases and transmission. Availability of high-quality genome assemblies for mosquitoes may help to better understand their population structure and to develop effective and safe vector-control approaches that we urgently need. For the development of high-quality genome assemblies, we need to construct a physical genome map, that shows the physical locations of genes or other DNA sequences of interest along the chromosomes. For this reason, we developed a new gene-based approach for the physical mapping of the mosquito genomes. This method was then used for the development of a physical map for Ae. albopictus. This study resulted in the generation of the first physical map of the Ae. albopictus genome. To understand population structure in Culicinae mosquitoes, we used mosquitoes from the Culex pipiens complex. Species in this complex transmit different arthropod-borne viruses or arboviruses. Notable is the West Nile Virus, which has triggered fatal infections and epidemics in Eastern and Central Europe, North America and is also known in Asia, Australia, Africa, and the Caribbean. We specifically focused on two subspecies in this complex, Cx. pipiens pipiens and Cx. pipiens molestus that are morphologically identical, but are different physiologically and behaviorally. Although they are spread globally in temperate regions, their population structure and taxonomic status remains unclear. The first goal of this study was to better understand the level of genomic differentiation of Cx. p. pipiens and Cx. p. molestus from different continents. We sequenced and compared the whole genomes of 40 individual mosquitoes from two locations in Eurasia and two in North America. Our study identified that Cx. p. molestus and Cx. p. pipiens represent different evolutionary units that are currently undergoing ecological speciation. The second goal was to study differences at the chromosome level between them. Using the Hi-C approach we detected presence of two different inversions in Cx. p. pipiens and Cx. p. molestus, which could potentially explain their different physiology and adaptation.
117

Effects of high incubation temperature on the developing small intestine and yolk sac of broiler chicks with insight into goblet cell development in the small intestine early posthatch

Reynolds, Krista Lynn 07 August 2019 (has links)
The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler's life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick. / Master of Science / The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler’s life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick.
118

Development and assessment of strategies for non-invasive prenatal diagnosis using fetal cells in maternal blood / Développement et évaluation de méthodes pour le diagnostic prénatal non-invasif à partir des cellules fœtales circulant dans le sang maternel

Emad, Ahmed Anwar Hasanin January 2014 (has links)
Abstract : Current prenatal diagnosis depends on invasive procedures and is thus offered only to high-risk pregnancies. Development of non-invasive prenatal diagnosis (NIPD) would change the risk-benefit ratio and make it likely that more women would benefit from prenatal testing. Scientists have documented the presence of rare fetal cells in maternal blood and envisioned targeting them with specific markers and their use in NIPD. Considering their extremely low frequency in maternal blood, fetal cells have been difficult to retrieve and use in clinical practice. Therefore, there is a pressing need for systematic sequential studies to evaluate their feasibility in NIPD. Generally, detection of rare cells within a large cell population carries great potentialities for the prospects of cancer management and NIPD. Manual scanning is very cumbersome and time-consuming Therefore; the first part of our project was, dedicated to the optimization of an effective strategy to evaluate retrieval of rare cells. We have developed a way of distributing a controlled number of target cells among hundreds of thousands of other cells on microscope slides. This strategy allows the precise evaluation of the retrieval of rare events and the comparizon of the efficacy of different techniques and enrichment approaches by knowing the definite number and locations of target cells on the slides. Furthermore, it allows the evaluation of hybridization of missed events. We have also developed a robust custom-made detection algorithm for rare cells using the MetaSystems automated platform and have used this strategy in the validation of manual and automatic scanning of 60 slides with a pre-defined number of rare male cells among a pure population of female cells using XY-FISH. Consequently, we tested the developed classifier for the detection of real fetal cells from maternal blood in both normal and aneuploid pregnancies with Down syndrome. We further evaluated the number of fetal cells with different methods of enrichments in the first and second trimesters. The data collected confirmed the early presence of fetal cells in all of the pregnancies tested and their frequencies were higher in cases of aneuploidies. Fetal cells are in a state of dynamic change throughout the pregnancy. Higher numbers of these cells can be obtained by optimizing the harvest time and methods of enrichment. We found that automatic scanning is more sensitive and reliable than manual detection. Furthermore, it alleviates the burden of scanning large numbers of cells and thus is more suitable for clinical application. We also demonstrated the feasibility of using rare cells in NIPD. Five microdissected amniotic fetal cells from 26 cases of normal and aneuploid pregnancies were quite enough to provide accurate NIPD through using whole genome amplification coupled with QF-PCR. Our findings laid the ground for the use of rare fetal cells in maternal blood for NIPD. // Résumé : Le diagnostic prénatal résulte encore aujourd’hui de procédures invasives, qui présentent des risques pour la grossesse. Le développement du diagnostic prénatal non-invasif (DPNI) changerait le rapport risque : bénéfice, rendant le diagnostic prénatal plus intéressant pour les femmes enceintes. Plusieurs chercheurs ont montré la présence de cellules fœtales dans le sang maternel et des travaux ont été entrepris afin de les cibler et de les utiliser éventuellement en DPNI. Toutefois, la faible concentration des cellules fœtales dans le sang maternel réduit les possibilités d’isolement ainsi que celles de leur utilisation en clinique. Un autre aspect technique du DPNI, le balayage manuel, est très laborieux, surtout en terme de temps technique. Il y a donc un besoin certain pour des études approfondies afin d’évaluer et d’améliorer la faisabilité du DPNI. La détection d’évènements rares dans une grande population cellulaire offre un potentiel pour le diagnostic en oncologie mais aussi en diagnostic prénatal. Dans cette thèse, la première étude était dédiée à l’optimisation d’une stratégie pour détecter les cellules rares. Nous avons développé une méthode d’étalement sur lame d’un nombre précis de cellules cibles parmi des centaines de milliers de cellules. Cette stratégie a permis d’évaluer le taux de détection d’évènements rares et de comparer l’efficacité des techniques d’enrichissement en connaissant le nombre exact et la localisation de cellules cibles sur les lames. De plus, il a été possible d’évaluer les problèmes d’hybridation des évènements manqués. Nous avons, par la suite, développé un algorithme robuste pour la détection de cellules rares en utilisant la plateforme de microscopie automatisée MetaSystems et utilisé cette approche dans la validation des balayages manuel et automatique d’un nombre précis de cellules mâles parmi une large population de cellules femelles marquées avec la technique FISH. Nous avons testé ce classificateur avec des échantillons de sang de femmes enceintes de grossesses normales et aneuploïdes et évalué la fréquence de cellules fœtales isolées par différentes méthodes d’enrichissement au cours des premier et second trimestres de grossesse. Les données accumulées ont confirmé la présence de cellules fœtales chez toutes les grossesses et leur fréquence plus élevée dans les grossesses aneuploïdes. Le nombre de cellules fœtales est dynamique tout au long de la grossesse. De plus, un nombre plus élevé de cellules fœtales peut être obtenu en optimisant le moment du prélèvement et les méthodes d’enrichissement. De plus, le balayage automatique s’est avéré plus sensible et constant que le balayage manuel, ce qui permet de balayer un grand nombre de cellules et devient plus approprié pour une application clinique. Nous avons aussi montré la faisabilité d’utiliser des cellules fœtales dans le cadre du DPNI. Cinq cellules amniotiques microdisséquées, provenant de grossesses normales et aneuploïdes, ont suffi pour poser un diagnostic prénatal par une combinaison de l’amplification du génome complet et de la technique QF-PCR (réaction quantitative en fluorescence d’amplification entraînée par une polymérase) permettant la détection d’anomalies chromosomiques. Nos résultats ouvrent la voie à l’utilisation de cellules fœtales dans le sang maternel pour le DPNI.
119

Définition du mécanisme de localisation des ARNm cen et ik2 aux centrosomes chez la Drosophile

Legendre, Félix 12 1900 (has links)
L’organisation cellulaire repose sur une distribution organisée des macromolécules dans la cellule. Deux ARNm, cen et ik2, montrent une colocalisation parfaite aux centrosomes. Ces deux gènes font partie du même locus sur le chromosome 2L de Drosophila melanogaster et leur région 3’ non traduite (3’UTR) se chevauchent. Dans le mutant Cen, le transport de Ik2 est perturbé, mais dans le mutant Ik2, la localisation de cen n’est aucunement affectée. Ces résultats suggèrent que cen est le régulateur principal de la co-localisation de cen et ik2 aux centrosomes et que cette co-localisation se produit par un mécanisme impliquant la région complémentaire au niveau du 3’UTR des deux transcrits. La localisation de cen au niveau des centrosomes dans les cellules épithéliales de l’embryon est conservée dans différentes espèces de Drosophile : D. melanogater, D. simulans, D. virilis et D. mojavensis. Cependant, la localisation de ik2 n’est pas conservée dans D. virilis et D. mojavensis, deux espèces dont les gènes cen et ik2 sont dissociés dans le génome. Ces résultats suggèrent que la proximité de Cen et Ik2 dans le génome est importante afin d’avoir un événement de co-localisation de ces deux transcrits. J’ai généré différentes lignées de mouches transgéniques dans lesquelles un transgène contenant la séquence GFP fusionnée à différentes partie de Cen (partie codante, 3’UTR, Cod+3’UTR) qui sont sous le contrôle du promoteur UAS et qui sont gal4 inductibles. La région codante de l’ARNm cen était suffisante pour avoir un ciblage précis du transcrit aux centrosomes. / Messenger RNA (mRNA) localization plays a key role in establishing cellular architecture and function. The centrocortin (cen) and IkB Kinase-like 2 (ik2) mRNAs are co-localized to centrosomes in embryonic epithelial cells. Interestingly, both of these genes are organized in a head-to-head configuration in the genome, with their 3’ untranslated regions (3’UTRs) overlapping on opposite DNA strands. Here we show that gene positioning of cen and ik2 is important for the co-localization of these transcripts during Drosophila embryogenesis. The localization of cen is conserved within the Drosophila phylogeny and ik2 cannot localize when it is separated from the cen locus. Also, loss of function mutants of cen show a complete loss of ik2 localization, proposing that cen is the main driver of the co-localization. Structure-function analysis revealed that the coding region of cen is necessary for its centrosomal targeting, suggesting that a cis-regulatory motif that drives its localization is located in the coding region. This study reveals for the first time the importance of gene positioning for RNA localization. We suggest a model where cen mRNA is the main driver of centrosomal localization, which may occur through post-transcriptional interaction/annealing of these mRNAs via their 3’UTRs.
120

Localização dos transcritos dos genes WNT5A e HOXB5 em carcinomas epidermóides de boca através da técnica de hibridização “in situ”. / WNT5A e HOXB5 localization study in oral squamous cell carcinoma with in situ hybridization.

Almeida, Fernanda Campos Sousa de 10 December 2004 (has links)
São freqüentes alterações em vias de sinalização de genes de desenvolvimento, no que diz respeito ao carcinoma epidermóide de boca (CEB). Vinte e nove casos de CEB e tecido não tumoral adjacente à neoplasia foram investigados através da técnica de hibridização “in situ". Os transcritos dos genes WNT5A e HOXB5 foram observados em todos os casos de tumor. A hibridização “in situ" revelou que o WNT5A estava mais expresso em tumores bem diferenciados. Adicionalmente, observou-se transcritos do WNT5A em glândulas salivares menores, estroma glandular, estroma tumoral e alguns vasos sanguíneos Entretanto, com respeito ao HOXB5 não foi possível estabelecer mudança do padrão do transcrito nos diferentes graus histológicos nas amostras de CEB. O HOXB5 também pôde ser identificado em alguns fragmentos de glândulas salivares menores, tecido muscular e em endotélio. Os resultados do presente estudo sugerem que a expressão dos genes WNT5A e HOXB5 podem estar relacionadas com a diferenciação e progressão do câncer de boca. / Disruption in developmental genes pathway are common in oral squamous cell carcinoma (OSCC). This study investigated the pattern of expression of two developmental genes, WNT5A and HOXB5, in 29 cases of OSCC and adjacent non tumoural tissue using in situ hybridization technique. Transcripts for WNT5A and HOXB5 were detected in all tumoral samples. In situ hybridization technique demonstrated that WNT5A transcripts were mainly detected in well differentiated tumors when compared with moderately and undifferentiated OSCC. WNT5A transcripts were also observed in accessory salivary glands, glandular stroma, and vessels. Therefore, for the HOXB5 transcript it was not possible to stability a relationship with the tumoral histological grade. The expression of HOXB5 transcripts in non tumoral samples was detected in salivary glands, glandular stroma, endothelium, and muscle. Results suggest that WNT5A and HOXB5 genes play a possible role in tumor differentiation and cancer progression.

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