O transporte de iodo para tireóide é mediado pelo simportador sódio-iodo (NIS), glicoproteína de 643 aminoácidos localizada na região basolateral da célula folicular que acopla a entrada de sódio e iodo para o interior da célula. A clonagem do gene NIS em 1996 foi o primeiro passo na investigação dos mecanismos moleculares responsáveis pela diminuição da captação do radioiodo nos tumores benignos e malignos da tireóide. Estudos prévios sobre a expressão do gene NIS baseados em quantificação do transcrito e/ou análise imuno-histoquímica da proteína, mostraram resultados bastante divergentes. A maioria dos estudos com RT-PCR mostrou redução ou até ausência do transcrito do NIS. Os estudos mais recentes de imunohistoquímica, no entanto, mostraram aumento da expressão da proteína NIS, ao invés de diminuição. Poucos foram os estudos que fizeram análise do transcrito e da proteína concomitantemente nas mesmas amostras. Este estudo teve como objetivo quantificar o RNAm do gene NIS e avaliar a expressão e localização celular da proteína NIS, através das técnicas de RT-PCR em tempo real e exame imunohistoquímico, respectivamente. Foram estudadas 30 amostras de nódulos de tireóide, sendo 14 nódulos benignos e 16 nódulos malignos, sempre pareados com o tecido não-tumoral do mesmo paciente. Através de exame cintilográfico, verificouse que 100% dos nódulos malignos e 85,7% dos benignos eram hipocaptantes. Houve diminuição da expressão gênica do NIS em 78,6% dos nódulos benignos, em 81,2% dos carcinomas utilizando o gene PSMC6 como controle interno e em 100% dos carcinomas com o gene GAPDH como controle interno. O exame imunohistoquímico da proteína NIS revelou positividade da proteína NIS no citoplasma em 100% dos tecidos não-tumorais, 100% dos nódulos benignos e 93,75% dos nódulos malignos, não sendo estatisticamente diferentes entre si. A positividade na membrana basolateral ocorreu em 23,3% das amostras não-tumorais, em 14,3% dos nódulos benignos e em 12,5% dos nódulos malignos, não se detectando diferença significativa entre os grupos. A comparação da intensidade da imunoexpressão do NIS no citoplasma entre os nódulos versus os tecidos não-nodulares mostrou que esta foi maior em 64,3% dos nódulos benignos e em 87,5% dos malignos. Houve associação entre diminuição da quantificação gênica do NIS tumoral e aumento da imuno-expressão da proteína NIS no citoplasma tumoral em 50% dos nódulos benignos, 87,5% dos nódulos malignos, quando se utilizou o GAPDH como controle interno e, em 68,75% dos nódulos malignos quando se utilizou o PSMC6. A diminuição da expressão gênica do NIS associada a maior imuno-positividade intracitoplasmática da proteína NIS se deve a provável incapacidade de migração da proteína para a membrana plasmática. / The iodide uptake by epithelial thyroid cells requires the expression of sodium iodide symporter (NIS), a transmembrane glycoprotein of 643 amino acids. NIS is located at basolateral plasma membrane of the thyroid follicular cells and couples the transport of iodide and sodium to this cells. NIS gene was cloned in 1996, being the first step of investigation of the mechanisms responsible for the lower uptake of radioiodide by benign and malignant thyroid tumors. Previous studies about expression of NIS gene based in quantification by RT-PCR and/or immunohistochemistry analysis showed divergent data. The majority of RT-PCR studies showed reduction or even absence of transcript of NIS in malignant tumors. Recent studies of immunostaining showed that many tumors overexpress rather than under express NIS. Only a few studies have made the analysis of the transcript and the protein at the same time in the same samples. The objective of this study was to investigate NIS transcript levels and the presence and location of NIS protein, using real time RT-PCR and immunohistochemistry, respectively. It was included 30 samples of thyroid tumors, 14 benign and 16 malignant ones, always compared to adjacent non-tumoral samples. Scintigraphic findings showed that 100% of malignant tumors and 87.5% of benign ones were ?cold?. RT-PCR data revealed lower gene expression in 78.6% of the benign tumors, 81.2% of the carcinomas using PSMC6 as a housekeeping gene and 100% of the carcinomas using GHPDH as a housekeeping gene, when paired to the normal tissue samples. Immunohistochemical staining revealed presence of NIS protein in 100% of the nontumoral samples, 100% of the benign tumors and 93.75% of the malignant tumors. No statistical differences were detect in this data. NIS protein was identified at basolateral membrane in 23.3% of non-tumoral samples, 14.3% of benign tumors and 12.5% of malignant tumors. No statistical differences were detect in this data. Higher quantities of intracytoplasmatic NIS protein were detect in 64.3% of benign tumors and in 87.5% of malignant tumors when compared to non-tumoral samples. Association between lower gene expression and higher presence of intracytoplasmatic NIS protein was found in 50% of benign tumors, 87.5% of malignant tumors using GHPDH as a housekeeping gene and 68.75% of malignant tumors using PSMC6 as a housekeeping gene. The reduced gene expression of NIS in thyroid tumors with strong intracytoplasmatic staining may be due to his incapacity in migrating to cellular membrane.

Orientador: Fernando Ferreira Costa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-08T16:15:41Z (GMT). No. of bitstreams: 1 Alberto_FernandoLopes_D.pdf: 5633645 bytes, checksum: 7354434461195623d47c6efe24126229 (MD5) Previous issue date: 2003 / Resumo: Câncer é o resultado de anomalias no genoma acumuladas ao longo do tempo e corresponde a doença genética mais freqüente na população humana. Os últimos anos têm presenciado enormes avanços tecnológicos que facilitaram o desenvolvimento de técnicas para análise em larga escala do conjunto dos genes expressos nos diferentes tecidos, sendo responsável pela explosão do conhecimento em medicina molecular. No presente trabalho avaliamos o transcriptoma da leucemia mielóide crônica através da técnica de ORESTES (Open Reading Frame Expressed Sequence Tags). As seqüências geradas foram agrupadas de acordo com sua homologia através do pacote de bioinformática Phrap. Essa estratégia aumentou o grau de cobertura genômica, já que as seqüências originais apresentavam tamanho máximo de 500 a 700 bases. Após a retirada dos contaminantes, obtivemos 2933 agrupamentos de seqüências (contigs) e 11568 seqüências isoladas. Cada contig representa um gene em potencial e o seu conjunto foi submetido a comparação com o banco de dados público nr para possibilitar a anotação e classificação funcional. Os agrupamentos ORESTES foram classificados em comunicação celular (19%); crescimento, desenvolvimento e manutenção celular (9%); metabolismo celular (30%); estrutura, motilidade e transporte celular (15%); função desconhecida (28%). Adicionalmente, estabelecemos o mapeamento cromossômico dos contigs obtidos, observando distribuição relativamente homogênea e proporcional representada em todos os cromossomos humanos. O mapeamento dos contigs gerados por ORESTES apresentou-se com padrão de distribuição semelhante ao observado por Venter e colaborasores, 2001. Comparamos o padrão de expressão obtido com o transcriptoma de medula óssea de paciente portador de anemia hemolítica hereditária (doença hematológica não neoplásica) gerado por SAGE (Serial Analysis of Gene Expression). Os genes encontrados foram ordenados de acordo com sua representatividade ou nível de expressão. Não houve correlação entre os padrões de expressão observados pos SAGE e por ORESTES. Do conjunto dos 100 genes mais representados nos ORESTES, dez foram selecionados para validação da expressão por PCR quantitativo em tempo real, utilizando o agente fluorescente SybrGreen I. Identificamos e confirmamos o aumento da expressão em nove genes na LMC. Destes, sete tinham aumento superior a 10 vezes o controle (CAMP, ABR, DEFA3, CSF3R, MLL2, S100A8 e MS4A3), com dois deles (DEFA3 e ABR) com aumento de cerca de 50 vezes ou mais. A análise funcional particularizada para cada um deste genes em LMC tem o potencial de identicar possíveis alvos para novas intervenções terapeuticas. O método mostrou-se poderoso para evidenciar e validar as diferenças de expressão gênica observadas pelas técnicas de seqüenciamento utilizadas anteriormente. Os dados deste trabalho constituem a primeira descrição do transcriptoma da leucemia mielóide crônica / Abstract: The complete collection of transcripts generated from the human genome cannot be predicted from the genome sequence, but should be directly determined for each tissue, due to variations of gene expression in different tissues and disease states, and because genes can encode multiple transcripts derived from alternate splicing and polyadenylation sites. As part of larger project that produced up to 1.2 million ORESTES (open reading frames expressed sequence tags) from different cancer tissues, we constructed a set of cDNAs obtained from bone marrow cells of patients with CML, that represented partial expressed gene sequences that are biased toward the central coding regions of the resulting transcripts (Dias-Neto E et al, Proc Nat Acad Sci USA 97:3491, 2000). The 27,361 ESTs were assembled into contigs using the Phrap package producing 2933 clusters containing 2 to 210 ESTs (leaving 11568 isolated sequences). Functional categories were attributed to the contigs on the basis of the annotation of the matched sequences in nr, into 5 major functional categories and 22 subcategories (cell communication (19%); cell growth, development and m contigs formed by the larger number of EST in bone marrow cells was co mpared with a control bone marrow sample obtained from a non-neoplastic hematologic condition (hereditary hemolytic anemia) and evaluated with SAGE (serial analysis of gene expression). Ten out of 100 most representative contigs had their expression data evaluated further by realtime quantitative PCR with Sybr Green I reagent, confirming the ORESTES data. Seven out of the 10 genes were more than 10-fold upregulated (CAMP, ABR, DEFA3, CSF3R, MLL2, S100A8 e MS4A3) and two additional genes were 50-fold or higher upregulated in CML (DEFA3 e ABR). The wealthy of information provided by this approach demonstrates its usefulness for the analysis of gene expression in specific hematopoietic tissues and diseases / Doutorado / Clinica Medica / Doutor em Clínica Médica

Orientadores: Marcos Antonio Machado, Juliana de Freitas Astúa / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T08:50:41Z (GMT). No. of bitstreams: 1 Kubo_KarenSumire_D.pdf: 11235043 bytes, checksum: fb3c7d7e7af4e5fc35ef4a27c3364fda (MD5) Previous issue date: 2011 / Resumo: O Citrus leprosis virus C (CiLV-C) é o agente causal da leprose dos citros, uma doença incomum transmitida pelo ácaro Brevipalpus phoenicis. Uma vez que o CiLV-C permanece confinado em lesões localizadas nas folhas, ramos e frutos sem causar infecção sistêmica, o vetor precisa se alimentar nestas lesões para adquirir o vírus. O objetivo deste trabalho foi analisar os perfis de expressão diferencial entre um genótipo resistente (tangor 'Murcott') e um suscetível (laranja 'Pera') em resposta à leprose dos citros e identificar os possíveis mecanismos de resistência envolvidos na resistência à doença. Por esse motivo, antes da instalação dos experimentos biológicos, nós aperfeiçoamos a detecção do CiLV-C em seu vetor, para certificação da aquisição viral. O experimento biológico incluiu quatro grupos: genótipo resistente ou suscetível infestados com ácaros virulíferos ou avirulíferos para CiLV-C. Com o intuito de se identificar genes diferencialmente expressos, nós utilizamos lâminas de microarranjo com sondas baseadas na base de dados do Citrus EST (CitEST). As análises estatísticas foram realizadas por two-way ANOVA considerando os fatores genótipo e a infecção pelo CiLV-C, de maneira a se encontrar respostas envolvidas na resistência ao CiLV-C. Os resultados foram interpretados por Gene Set Enrichment Analysis (GSEA). Os resultados sugerem que existem receptor-like proteins (RLP) e receptor-like kinase (RLK) que podem reconhecer o vírus ou o ácaro, ativando uma resposta de defesa baseada na assinatura de 'Ca POT.2+' e ativação da via do ácido salicílico. Estudos adicionais ainda são necessários para verificar se a resposta de defesa pode estar relacionada à resistência sistêmica adquirida (SAR) / Abstract: Citrus leprosis virus C (CiLV-C) is the causal agent of citrus leprosis, an unusual disease transmitted by the mite Brevipalpus phoenicis. Since CiLV-C remains confined in localized lesions in leaves, stems and fruits without causing systemic infection, the vector needs to feed in these lesions to acquire the virus. The aim of this work was to analyze the differential gene expression profiles between resistant ('Murcott' tangor) and susceptible ('Pera' sweet orange) citrus genotypes in response to CiLV-C, and to identify possible mechanisms involved in disease resistance. For this reason, before the biological experiments were set, we improved the detection of CiLV-C in the mite vector to ensure virus acquisition. The biological experiment consisted in four groups: susceptible or resistant genotype infested with CiLV-C viruliferous or nonviruliferous mites. In order to identify differentially expressed genes, we used microarray chips designed using the Citrus EST database (CitEST). The statistical analysis was performed by two-way ANOVA considering the genotype and the infection by CiLV-C, aiming to find defense responses against CiLV-C. The results were interpreted by Gene Set Enrichment Analysis (GSEA) and led to the hypothesis that receptor-like proteins (RLP) and receptor-like kinase (RLK) may recognize the virus or the mite triggering a defense response based on 'Ca POT.2+' signature and activation of Salicylic acid pathway (SA). Further studies are necessary to evaluate if the defense response could be related to the development of systemic acquired resistance (SAR) / Doutorado / Bioquimica / Doutor em Biologia Funcional e Molecular

Le trypanosome est le parasite responsable de la maladie du sommeil chez l’homme et de la Nagana chez le bétail. Afin d’échapper au système immunitaire de son hôte mammifère, il remplace périodiquement la protéine VSG (Variant Surface Glycoprotein) présente en 10 millions d’exemplaires à sa surface. Ce mécanisme a pour nom la variation antigénique. <p>Pour être exprimé, le gène de VSG (VSG) doit se trouver en fin d’un site d’expression (ES) particulier. Cet ES est polycistronique, télomérique et transcrit par une ARN polymérase de type ribosomique (Pol I). 20 à 40 ESs similaires et un millier de VSGs sont recensés dans le génome du trypanosome. Cependant, un seul ES est totalement transcrit (actif) et un seul VSG est exprimé. La variation antigénique est donc possible par deux mécanismes: soit l’activation d’un autre ES, soit le remplacement du VSG dans l’ES actif. La base de ce système est l’activation d’un seul ES à la fois (contrôle monoallélique).<p>Au laboratoire, un modèle a été proposé où la transcription s’initie au niveau de tous les ESs mais n’aboutit au VSG que dans le cas de l’ES actif (Vanhamme et al. 2000). Dans ce cas uniquement, le transcrit primaire subit une maturation correcte (épissage et polyadénylation) et est exporté dans le cytoplasme. Etant donné que des transcrits Pol I subissent une maturation identique à des transcrits Pol II, la régulation s’effectuerait par recrutement d’une machinerie d’élongation/maturation de l’ARN de type Pol II (Pol II « RNA factory »). Cette dernière serait uniquement localisée au niveau de l’ES actif dans le compartiment nucléaire appelé ES body (Navarro and Gull, 2001).<p>Durant cette thèse, diverses stratégies ont été élaborées pour tester la validité du modèle. La première visait à comparer l’état de maturation d’un ES en fonction de son activité. Nos résultats ont appuyé l’idée que les transcrits d’ESs ayant subi une maturation correcte provenaient préférentiellement de l’ES actif mais le(s) facteur(s) en quantité limitante ne permettant cette maturation qu’au niveau de l’ES actif doivent encore être identifiés. Le seconde stratégie analysait l’acétylation des histones ainsi qu’un éventuel attachement différentiel à la matrice nucléaire de l’ES suivant son activité. Le niveau d’acétylation d’un ES lorsqu’il est actif n’a pu être étudié. Des résultats préliminaires en faveur d’une association préférentielle de l’ES à la matrice nucléaire lorsqu’il est actif ont été obtenus. Enfin, nous avons cloné deux homologues d’un facteur général de la transcription appelé TFIIS. Ce dernier permet à la Pol de redémarrer lorsqu’elle est bloquée par un site de pause. Individuellement chacun de ces facteurs ne semble pas être essentiel au trypanosome. Cependant, un retard de croissance a été observé lorsque les deux facteurs sont invalidés dans la même lignée cellulaire. Ce phénotype particulier doit être caractérisé. En parallèle, nous avons envisagé de caractériser le complexe de la Pol I du trypanosome. Cette stratégie constituait la manière la plus simple de mettre en évidence un éventuel contact physique et/ou fonctionnel entre la Pol I transcrivant l’ES et la machinerie d’élongation/maturation de l’ARN de type Pol II « RNA factory ». 5 sous-unités du complexe ont été identifiées, associées à une protéine de fonction inconnue ainsi qu’à des histones. L’identification d’autres protéines associées au complexe constitue notre perspective principale. La phosphorylation de la plus grande sous-unité du complexe a été démontrée mais son rôle doit encore être élucidé.<p> / Doctorat en sciences, Spécialisation biologie moléculaire / info:eu-repo/semantics/nonPublished

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: With a cure for HIV and AIDS still absent, non-nucleoside reverse transcriptase inhibitors (NNRTIs) play a major role in the current antiretroviral treatments used, which have shown to improve and prolong the lives of HIV patients significantly. However, with rapid mutations of the HI virus, the use of these drugs is becoming limited, thereby highlighting the need for the development of new NNRTIs. Previous work by our research team has led to the development of a cyclopropyl-containing indole-based compound with an inhibition activity (IC50 value) of 0.1 μM, as determined in an in vitro single-cycle, non-replicative phenotypic assay. Therefore, in this project, we focussed on enhancing the intermolecular interactions of our compound to three major areas in the NNRTI binding pocket, namely the Tyr181, the Val179, and the Lys101 binding pockets. Hereby we were able to obtain both improved and lower potencies, with our most active compound having an inhibition activity (IC50 value) of 1 nM. For the interaction to the Tyr181 binding pocket, we were thus unable to synthesise a heterocyclic ring system onto our molecule as opposed to the previously used phenyl ring. Secondly, for the interaction to the Lys101 binding pocket we were able to synthesise a tetrazole ring system and an amide functionality onto the 2-position of the indole. Lastly, in our quest to synthesise the cyclopropyl moiety onto our compound for the interaction in the Val179 binding pocket, we were able to investigate the full inhibition effect of this interaction by synthesising a similar compound with no interaction in this binding pocket. Moreover, we were able to synthesise a new compound with a methoxy moiety for this interaction with an inhibition activity (IC50 value) of 1 nM. With this compound only being submitted for efficacy evaluation as a racemic compound mixture, this opened a new door for research possibilities for our team. / AFRIKAANSE OPSOMMING: In die awesigheid van 'n geneesmiddel vir MIV en VIGS, speel nie-nukleosied omkeerbare transkripsie inhibitore ("NNRTIs")'n groot rol in die huidige antiretrovirale behandeling. Ongelukkig ondergaan die MI virus mutasies, wat dus die gebruik van hierdie antiretrovirale middels beperk. Hierdie beklemtoon dus die noodsaaklikheid vir die ontwikkeling van nuwe "NNRTIs". Vorige werk wat deur ons navorsings groep verrig is, het gelei tot die ontwikkeling van "n siklopropiel bevattende indol verbinding, met "n inhibisie aktiwiteit ("IC50" waarde) van 0.1 μM. Gevolglik, het ons in hierdie projek gefokus om die intermolekulêre interaksies van hierdie verbinding in drie hoof areas in die "NNRTI" bindings ruimte te verbeter, genaamd die Tyr181, die Val179, en die Lys101 bindings ruimtes. Hierdie projek het dus beide verbeterde en ook laer inhibisie aktiwiteits resultate gelewer, waar die mees aktiewe verbinding 'n inhibisie aktiwiteit ("IC50" waarde) van 1 nM behaal het. Vir die interaksie na die Tyr181 bindings ruimte, was ons dus onsuksesvol om 'n heteroaromatiese ring te sintetiseer as plaasvervanger vir die oorspronklike feniel ring. Tweedens, vir die interaksie na die Lys101 bindings ruimte, was ons in staat om 'n tetrazol ring en 'n amied funksionaliteit aan die 2-posisie van die indol te sintetiseer. In ons stryd om die siklopropiel ring aan ons verbinding te sintetiseer vir die interaksie in die Val179 bindings ruimte, was ons in staat om die volledige effek van hierdie interaksie te bepaal deur 'n soortgelykke verbinding te sintetiseer met geen interaksie in die Val179 bindings ruimte nie. Daarenbowe, het ons 'n verbining gesintetiseer met 'n inhibisie aktiwiet ("IC50" waarde) van 1 nM, waarvan die aktiwitiet van slegs die rasemiese mengsel van die verbinding bepaal is. Hierdie vinding het dus 'n nuwe navorsings deur vir ons groep geopen.

published_or_final_version / Anatomy / Master / Master of Philosophy

Organic nitrates, such as nitroglycerine (NTG), are widely used for their potent vasodilator capacity in the management of coronary artery disease and heart failure. Unfortunately, their beneficial effect is rapidly lost due to the development of nitrate tolerance, which is translated by an impaired vasorelaxation to NTG and an increased oxidative stress production. Although the mechanisms of the development of nitrate tolerance are still not fully elucidated, much interest has been focused in treating nitrate-receiving patients together with other drugs in order to overcome the development of nitrate tolerance. The Nitric Oxide generating enzyme, eNOS, and the superoxide anion generating enzyme, NAD(P)H oxidase, have been suggested to play a role in the development of nitrate tolerance. The aim of this study was to analyse the underlying mechanism by which ramipril, an ACE inhibitor and rosuvastatin, a new molecule of the statin class, are able to protect against the development of nitrate tolerance in the aortas isolated from rats, wild-type (wt) and eNOS-/- mice. These results show that ramipril as well as rosuvastatin are able to protect against the development of nitrate tolerance in the wt and eNOS-/- mice aortas suggesting that eNOS is not necessary for their protective effect. The aortas from nitrate tolerant rats and mice showed a significant increase in the NAD(P)H oxidase activation compared to the aortas from the control and from the co-treated ramipril+NTG or rosuvastatin+NTG animals. In line with these findings were the results obtained by RT-PCR analysis: the mRNA expression of the different subunits of the NAD(P)H oxidase, such as gp91phox, p22phox, were significantly decreased after rosuvastatin or ramipril treatment in wt and eNOS-/- mice aortas. Apocynin, the NAD(P)H oxidase inhibitor was also able to inhibit the development of nitrate tolerance in the rat and mouse aortas. In conclusion, these results suggest that rosuvastatin and ramipril are able to protect against the development of nitrate tolerance by counteracting the nitrate-induced oxidative stress. The mechanism of protection involves a direct interaction with the NAD(P)H oxidase pathway and seems to be completely independent of the eNOS pathway.

Louis, Tong Kwok-leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 121-130). / Abstracts in English and Chinese. / ABSTRACT --- p.I / ACKNOWLEDGEMENTS --- p.III / LIST OF CONTENTS --- p.IV / LIST OF TABLES --- p.VIII / LIST OF FIGURES --- p.X / ABBREVIATIONS --- p.XII / GENERAL ABBREVIATIONS --- p.XII / VARIOUS NOMENCLATURES OR ABBREVIATIONS FOR SRSVS --- p.XIII / OBJECTIVES OF THE STUDY --- p.XIV / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- HISTORICAL PERSPECTIVE --- p.2 / Chapter 1.2 --- CLINICAL FEATURES OF HUMAN SRSV INFECTION --- p.10 / Chapter 1.3 --- EPIDEMIOLOGY --- p.12 / Chapter 1.4 --- PHYSICAL CHARACTERISTICS OF SRSV --- p.14 / Chapter 1.5 --- STABILITY OF NORWALK VIRUS --- p.15 / Chapter 1.6 --- DIAGNOSTIC TOOLS FOR SRSVS --- p.15 / Chapter 1.7 --- GENOMIC ORGANIZATION OF SRSVS --- p.16 / Chapter 1.8 --- MOLECULAR TECHNOLOGIES --- p.19 / Chapter CHAPTER 2 --- MATERIALS --- p.20 / Chapter 2.1 --- FAECAL SAMPLES FROM 1986 TO 1992 --- p.21 / Chapter 2.2 --- OTHER FAECAL SAMPLES FROM 1995 TO 1998 --- p.21 / Chapter 2.3 --- AGE GROUPS OF ALL THE SAMPLES --- p.21 / Chapter CHAPTER 3 --- METHODS --- p.23 / Chapter 3.1 --- EXTRACTION OF RNA FROM PATIENT STOOL OR VOMIT SAMPLES --- p.24 / Chapter 3.2 --- REVERSE TRANSCRIPTION - POLYMERASE CHAIN REACTION (RT-PCR) FOR SRSVS --- p.25 / Chapter 3.2.1 --- Principle of RT-PCR assay for SRSV --- p.25 / Chapter 3.2.2 --- Reverse transcription (cDNA Synthesis) --- p.26 / Chapter 3.2.3 --- Polymerase chain reaction --- p.26 / Chapter 3.2.4 --- Electrophoresis (in the PCR product room) --- p.31 / Chapter 3.2.5 --- Controls for PCR assay --- p.32 / Chapter 3.2.6 --- Interpretation of SRSV polymerase gene PCR --- p.32 / Chapter 3.3 --- RT-PCR USING INOSINE CONTAINING PRIMERS FOR THE CAPSID REGIONS --- p.34 / Chapter 3.3.1 --- RT-PCR for the capsid region of SRSV genome --- p.34 / Chapter 3.3.2 --- Interpretation of SRSV capsid gene PCR --- p.36 / Chapter 3.4 --- SOLID PHASE IMMUNE ELECTRON MICROSCOPY FOR THE DETECTION OF SRSV --- p.37 / Chapter 3.5 --- OPTIMIZATION OF CONDITIONS FOR SRSV RT-PCR --- p.37 / Chapter 3.5.1 --- Titration of primers --- p.37 / Chapter 3.5.2 --- Titration of MgCl2 --- p.38 / Chapter 3.5.3 --- "Titration ofdNTPs, MgCl2 and Taq polymerase (pH 9.0)" --- p.38 / Chapter 3.6 --- SPECIFICITY OF SRSV RT-PCR --- p.38 / Chapter 3.7 --- PURIFICATION OF PCR PRODUCTS PRIOR TO CLONING …… --- p.38 / Chapter 3.8 --- CLONING OF THE PURIFIED DNA INTO pGEM-T EASY VECTOR --- p.39 / Chapter 3.8.1 --- Introduction --- p.39 / Chapter 3.8.2 --- Sequence of the pGEM-T Easy Vector --- p.42 / Chapter 3.8.3 --- Ligation --- p.44 / Chapter 3.8.4 --- Transformation of competent bacterial cells --- p.44 / Chapter 3.8.5 --- Small-scale preparations of plasmid DNA --- p.45 / Chapter 3.8.6 --- Purification of miniprep using QIAprep Miniprep --- p.45 / Chapter 3.8.7 --- Restriction analysis of small-scale preparations of plasmid DNA --- p.45 / Chapter 3.9 --- CYCLE SEQUENCING OF CLONED SRSV AMPLICONS --- p.46 / Chapter 3.9.1 --- Targets for Sequencing --- p.46 / Chapter 3.9.2 --- Procedures of cycle sequencing --- p.46 / Chapter 3.9.3 --- Gel electrophoresis --- p.48 / Chapter 3.9.4 --- Sequencing conditions --- p.49 / Chapter 3.10 --- SEQUENCE ANALYSIS --- p.49 / Chapter CHAPTER 4 --- REAGENTS AND BUFFERS --- p.51 / Chapter 4.1 --- REAGENTS AND BUFFERS FOR RNA EXTRACTION --- p.52 / Chapter 4.2 --- REAGENTS AND BUFFERS FOR REVERSE TRANSCRIPTION (cDNA SYNTHESIS) --- p.52 / Chapter 4.3 --- REAGENTS AND BUFFERS FOR PCR --- p.53 / Chapter 4.4 --- GEL ELECTROPHORESIS OF PCR PRODUCTS --- p.53 / Chapter 4.5 --- PURIFICATION OF PCR PRODUCTS --- p.54 / Chapter 4.6 --- REAGENTS FOR CLONING THE DNA INSERT INTO pGEM-T EASY VECTOR --- p.54 / Chapter 4.6.1 --- "pGEM-T Easy Vector System (Promega Corporation, USA)" --- p.54 / Chapter 4.6.2 --- Isopropylthio-β-D-galactoside (IPTG) stock solution --- p.54 / Chapter 4.6.3 --- X-Gal --- p.54 / Chapter 4.6.4 --- Luria-Bertani (LB) medium --- p.55 / Chapter 4.6.5 --- LB plates with ampicillin --- p.55 / Chapter 4.6.6 --- LB plates with ampicillin/IPTG/X-Gal --- p.55 / Chapter 4.6.7 --- SOC medium --- p.55 / Chapter 4.6.8 --- Mini-prep purification --- p.56 / Chapter 4.6.9 --- Mini-prep analysis --- p.56 / Chapter 4.6.9.1 --- Lambda DNA-Hind IIIφX-174 DNA-Hae III Digest --- p.56 / Chapter 4.6.9.2 --- Not I --- p.58 / Chapter 4.7 --- REAGENTS AND BUFFERS FOR CYCLE SEQUENCING --- p.58 / Chapter 4.7.1 --- SequiTherm EXCEĹёØ II Long-Rea´dёØ DNA Sequencing Kit-AL´FёØ --- p.58 / Chapter 4.7.2 --- Sequencing primers --- p.59 / Chapter 4.8 --- REAGENTS FOR SEQUENCING GEL CASTING --- p.59 / Chapter CHAPTER 5 --- RESULTS --- p.61 / Chapter 5.1 --- RESULTS OF RT-PCR OPTIMIZATION --- p.62 / Chapter 5.1.1 --- Magnesium chloride and pH of PCR reaction buffer --- p.62 / Chapter 5.1.2 --- Concentration of primers --- p.64 / Chapter 5.1.3 --- "Titration of dNTPs, MgCl2 and Taq polymerase (pH 9.0)" --- p.65 / Chapter 5.2 --- RESULT OF SENSITIVITY TEST --- p.66 / Chapter 5.3 --- RESULTS OF SPECIFICITY TEST --- p.67 / Chapter 5.4 --- RESULTS OF THE PCR USING INOSINE CONTAINING POL PRIMERS --- p.70 / Chapter 5.5 --- RESULTS OF PCR USING INOSINE CONTAINING CAPSID PRIMERS --- p.73 / Chapter 5.6 --- RESULTS OF SOME SAMPLES RETESTED BY SPIEM --- p.75 / Chapter 5.7 --- RESULTS OF SPORADIC OUTBREAKS --- p.77 / Chapter 5.7.1 --- A sporadic outbreak in 1996 --- p.77 / Chapter 5.7.2 --- Sporadic outbreak in a kindergarten in 1997 --- p.79 / Chapter 5.7.3 --- Sporadic outbreak at a hotel in 1998 --- p.79 / Chapter 5.7.4 --- Application of the RT-PCR to contaminated shellfish --- p.80 / Chapter 5.8 --- RESULTS OF MINI PREP ANALYSIS WITH NOT I DIGESTION --- p.85 / Chapter 5.9 --- RESULT OF ELECTROPHEROGRAM OF A SELECTED SPECIMEN FROM THE AUTOMATIC SEQUENCING --- p.86 / Chapter 5.9 --- RESULT OF ELECTROPHEROGRAM OF A SELECTED SPECIMEN FROM THE AUTOMATIC SEQUENCING --- p.86 / Chapter 5.10 --- RESULTS OF ALL TRIMMED DNA SEQUENCES --- p.87 / Chapter CHAPTER 6 --- DISCUSSION --- p.112 / REFERENCES --- p.122 / APPENDIX --- p.131 / APPENDIX I: Electron micrograph of SRSV particles --- p.132 / APPENDIX II: Confirmation for specificity test --- p.133 / APPENDIX III: Sequencing amplicons using capsid primers --- p.135 / APPENDIX IV: Sequencing amplicons (outbreak) using pol primers --- p.136 / APPENDIX V: Electropherogram (direct sequencing) --- p.138 / APPENDIX VI: Other RT-PCR results using pol primers --- p.139 / APPENDIX VII: Results of RT-PCR using capsid primers --- p.149 / APPENDIX VIII: Mini prep analysis --- p.158

Ho Hei Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 189-199). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Epidemiology of the Severe Acute Respiratory Syndrome (SARS) Outbreak --- p.2 / Chapter 1.2 --- The SARS Coronavirus --- p.3 / Chapter 1.2.1 --- Genome organization --- p.7 / Chapter 1.2.2 --- Structural proteins --- p.9 / Chapter 1.2.3 --- Non-structural proteins --- p.11 / Chapter 1.3 --- Introduction to SARS-CoV nsp10 Protein --- p.14 / Chapter 1.4 --- Introduction to SARS-CoV RNA-dependent RNA Polymerase (RdRp) Protein --- p.17 / Chapter 1.5 --- Objectives of the Present Study --- p.25 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- Construction of Glutathione S-Transferase (GST) Fusion/Green Fluorescence Protein (GFP) N1 and C1 Fusion nsplO --- p.26 / Chapter 2.1.1 --- Primer design --- p.26 / Chapter 2.1.2 --- Gene amplification by PCR --- p.28 / Chapter 2.1.3 --- Purification of PCR product --- p.30 / Chapter 2.1.4 --- Enzyme restriction --- p.31 / Chapter 2.1.5 --- Ligation --- p.33 / Chapter 2.1.6 --- Transformation --- p.34 / Chapter 2.1.6.1 --- Preparation of competent cell DH5α --- p.34 / Chapter 2.1.7 --- Mini scale plasmid preparation --- p.36 / Chapter 2.2 --- Subcellular Localization Study --- p.39 / Chapter 2.2.1 --- Midi scale plasmid preparation --- p.39 / Chapter 2.2.2 --- Transfection of GFP recombinant plasmids --- p.41 / Chapter 2.2.2.1 --- Cell culture of Vero E6 cell line --- p.41 / Chapter 2.2.2.2 --- Lipofectamine based transfection --- p.41 / Chapter 2.2.3 --- Fluorescent microscopic visualization --- p.42 / Chapter 2.2.4 --- Western blotting for GFP fusion protein expression --- p.43 / Chapter 2.2.4.1 --- Protein extraction --- p.43 / Chapter 2.2.4.2 --- Protein quantification --- p.44 / Chapter 2.2.3.4 --- SDS-PAGE analysis --- p.45 / Chapter 2.3 --- "Expression of GFP-nsp10 in Vero E6 cells, SARS-CoV Infected Vero E6 Cells and Convalescent Patients' Serum" --- p.47 / Chapter 2.3.1 --- Cell-based immunostaining of VeroE6 cells and SARS-CoV infected Vero E6 cells --- p.47 / Chapter 2.3.1.1 --- Immobilization of Vero E6 cells and SARS-CoV infected Vero E6 cells --- p.47 / Chapter 2.3.1.2 --- Preparation of monoclonal antibodies against SARS-CoV nsp10 --- p.48 / Chapter 2.3.1.3 --- Immunostaining of SARS-CoV nsp10 in Vero E6 cells and SARS-CoV VeroE6 cells --- p.48 / Chapter 2.3.1.4 --- Fluorescent microscopic visualization --- p.49 / Chapter 2.3.2 --- Detection of SARS-CoV nsplO expression in SARS-CoV infected convalescent patients' serum --- p.50 / Chapter 2.3.2.1 --- Western blotting of SARS-CoV nsp10 by SARS-CoV infected convalescent patients' serum --- p.50 / Chapter 2.4 --- Expression of GST fusion SARS-CoV nsp10 in E.coli --- p.51 / Chapter 2.4.1 --- Preparation of competent cells --- p.51 / Chapter 2.4.2 --- Small scale expression --- p.51 / Chapter 2.4.3 --- Large scale expression of GST-nsp10 in optimized conditions --- p.54 / Chapter 2.5 --- Purification of GST fusion SARS-CoV nsp10 --- p.55 / Chapter 2.5.1 --- Glutathione Sepharose 4B affinity chromatography --- p.55 / Chapter 2.5.2 --- Superdex 75 gel filtration chromatography --- p.56 / Chapter 2.6 --- "CD Measurement, NMR and Crystallization Study of SARS-CoV nsp10" --- p.57 / Chapter 2.6.1 --- CD measurement --- p.57 / Chapter 2.6.2 --- NMR spectroscopy --- p.58 / Chapter 2.6.3 --- Crystallization of nsp10 --- p.58 / Chapter 2.7 --- "Glutathione-S-Sepharose Pull-down assay, 2D Gel Electrophoresis and Mass Spectrometry" --- p.59 / Chapter 2.7.1 --- GST pull-down assay --- p.59 / Chapter 2.7.2 --- Two-dimension gel electrophoresis --- p.59 / Chapter 2.7.2.1 --- First dimensional isoelectric focusing (IEF) --- p.59 / Chapter 2.7.2.2 --- Second dimension SDS-PAGE --- p.60 / Chapter 2.7.2.3 --- Silver staining --- p.61 / Chapter 2.7.3 --- Protein identification by mass spectrometry --- p.63 / Chapter 2.7.3.1 --- Data acquisition --- p.65 / Chapter 2.8 --- Proliferative study of SARS-CoV nsp10 in VeroE6 Cell Line and Mouse Splenocytes --- p.66 / Chapter 2.8.1 --- Assay of mitogenic activity by 3H-thymidine incorporation --- p.66 / Chapter 2.9 --- "Cloning, Expression and Purification of GST fusion SARS-CoV RNA-dependent RNA Polymerase (RdRp) Full- length Protein" --- p.67 / Chapter 2.9.1 --- Construction of GST-RdRp-full length expression plasmid --- p.67 / Chapter 2.9.2 --- Expression and purification of GST-RdRp full-length protein --- p.68 / Chapter 2.10 --- "Cloning, Expression and Purification of GST Fusion SARS-CoV RNA-dependent RNA Polymerase (RdRp) Catalytic Domain" --- p.70 / Chapter 2.10.1 --- Construction of GST-RdRp Catalytic Domain (p64) and MBP-RdRp-p64 expression plasmids --- p.70 / Chapter 2.10.2 --- Expression and purification of GST fusion catalytic domain of SARS-CoV RdRp (GST-p64) --- p.71 / Chapter 2.10.3 --- Expression and purification of MBP fusion catalytic domain of SARS-CoV RdRp --- p.72 / Chapter 2.11 --- "Cloning, Expression and Purification of the His-thioredoxin Fusion N-terminal Domain of SARS-CoV RdRp (pET32h-pl2)" --- p.74 / Chapter 2.11.1 --- Construction of His-thioredoxin fusion N-terminal domain of SARS-CoV RdRp (pET32h-pl2) expression plasmid --- p.74 / Chapter 2.11.2 --- Expression and purification of His- thioredoxin fusion N-terminal domain of SARS-CoV RdRp (pET32h-pl2) --- p.74 / Chapter 2.12 --- Interaction Study of RdRp Catalytic Domain and N-terminal Domain --- p.76 / Chapter 2.13 --- Electrophoretic Mobility Shift Assay of SARS-CoV Genomic RNA Strands with RdRp Full-length sequence --- p.76 / Chapter 2.13.1 --- Preparation of RNA transcripts --- p.76 / Chapter 2.13.2 --- EMSA --- p.77 / Chapter 2.14 --- Non-radiometric and Radiometric RdRp Assays --- p.78 / Chapter 2.14.1 --- Non-radiometric RdRp assay--luciferase coupled enzyme assay --- p.78 / Chapter 2.14.2 --- Radiometric RdRp assay ´ؤ filter-binding enzyme assay --- p.79 / Chapter 2.15 --- Western Blot Analysis for Interaction Study --- p.80 / Chapter Chapter 3 --- Results and Discussion on SARS-CoV nsplO --- p.81 / Chapter 3.1 --- "Cloning, Expression and Purification of SARS-CoV nsp10 in Prokaryotic Expression System" --- p.81 / Chapter 3.1.1 --- Cloning and expression of SARS-CoV nsp 10 --- p.81 / Chapter 3.1.2 --- Purification of GST-nsp10 by GST affinity chromatography --- p.84 / Chapter 3.1.3 --- Purification of nsp10 by size exclusion chromatography --- p.85 / Chapter 3.1.4. --- "Yield, purity and stability of SARS-CoV nsp 10" --- p.88 / Chapter 3.2 --- SARS-CoV nsp10 Sequence Alignment and Protein Structure Prediction --- p.89 / Chapter 3.2.1. --- Sequence alignment of SAR-CoV nsp10 with known viral proteins --- p.91 / Chapter 3.2.2 --- Protein structure prediction - homology modeling --- p.93 / Chapter 3.3 --- Circular Dichroism Analysis of nsp10 --- p.96 / Chapter 3.3.1 --- CD spectrum of SARS-CoV nsp10 --- p.98 / Chapter 3.3.2. --- Effect of divalent metal ions on SARS-CoV nsp10 --- p.99 / Chapter 3.4 --- Nuclear Magnetic Resonance Analysis of nsp10 --- p.101 / Chapter 3.4.1 --- Sample preparation for NMR Experiment --- p.102 / Chapter 3.4.2 --- Protein structure determination by NMR --- p.103 / Chapter 3.5 --- Crystallization of SARS-CoV nsp10 --- p.105 / Chapter 3.5.1 --- Sample preparation of nsp10 for crystallization --- p.105 / Chapter 3.5.2 --- Screening conditions for crystallization --- p.106 / Chapter 3.6 --- "Antigenic, Immunofluorescene and Subcellular Localization Studies on the SARS-CoV nsp10" --- p.110 / Chapter 3.6.1 --- Antigenic and immunofluorescene studies on the SARS-CoV nsp10 --- p.110 / Chapter 3.6.2 --- Subcellular localization of SARS-CoV nsp10 --- p.115 / Chapter 3.7 --- Proliferative Study of nsp10 --- p.120 / Chapter 3.7.1. --- Influence of proliferative effect on the host cell --- p.121 / Chapter 3.8 --- A Proteomics Strategy for Interaction Study of nsp10 --- p.124 / Chapter 3.8.1 --- 2D SDS-PAGE analysis of proteins associating with the nsp10 bait --- p.125 / Chapter 3.8.2 --- Silver staining of proteins associating with the nsp10 bait and their identification by mass spectrometry --- p.127 / Chapter 3.9 --- Discussion on SARS-CoV nsp10 --- p.129 / Chapter Chapter 4 --- Results and Discussion on SARS-CoV RdRp / Chapter 4.1 --- "Cloning, Expression and Purification of SARS-CoV RdRp Full-length, Catalytic Domain and N-terminal Domain" --- p.139 / Chapter 4.2 --- Interaction Study of RdRp Catalytic Domain and its N-terminal Domain --- p.147 / Chapter 4.3 --- Functional Analysis of RNA Binding by the SARS-CoV RdRp --- p.149 / Chapter 4.4 --- Characterization of RdRp by Non-radioactive RdRp Assay ´ؤ Luciferase-coupled Enzyme Assay --- p.152 / Chapter 4.5 --- Characterization of RdRp by Radioactive RdRp Assay ´ؤ 32P Incorporation Assay --- p.157 / Chapter 4.6 --- Discussion on SARS-CoV RdRp --- p.161 / Chapter Chapter 5 --- General Discussion / General Discussion --- p.170 / Appendix --- p.172 / References --- p.189

In most eukaryotes, chromosomes ends are protected by telomeres which are formed by repetitive DNA, specialized binding proteins, and higher order structures. Telomeres become shorter following replication due to the positioning and degradation of terminal RNA primers, as well as resection by nucleases. Extensive telomere shortening over many cell cycles elicits a DNA damage checkpoint that culminates in senescence or, in the absence of tumor suppressor pathways, apoptosis. These effects block the expansion of cells with unstable genomes, but can also precipitate disease in tissues that rely on regeneration for function. In many unicellular eukaryotes and proliferative human cells including cancer cells, telomeres can be maintained by the telomerase reverse transcriptase (TERT) and its associated RNA (TR). The elongation of telomeric DNA by telomerase depends on the telomerase essential N-terminal (TEN) and C terminal reverse transcriptase (RT) domains. We found that human TEN interacted with single-stranded telomeric DNA and restored function, in trans, to an hTERT mutant lacking hTEN. Telomerase required hTEN residues for activity, telomere maintenance, and extension of cellular replicative lifespan. Two inactive hTERT variants bearing mutations in TEN and RT domains, respectively, cooperated to regenerate telomerase activity in vitro. hTEN interacted with several regions of hTERT suggesting that dimerization may occur via TEN-TERT interactions. The in vivo defect of certain hTEN mutants may involve an inability to interact with factors that recruit the enzyme to the telomere and/or stimulate activity. Human homologs of the S. cerevisiae recruitment factor Est1 interacted with telomerase in a species-specific manner. The TPR domain of hEST1A interacted with the N-terminus of hTERT. The TPR domain of ScEst1 was required for telomere length maintenance by telomerase, and, paradoxically, also negatively regulated telomere length. In preliminary experiments, hTERT interacted with hPOT1/hTPP1. This interaction may stimulate the elongation of telomeres by telomerase. The DNA and protein interactions described herein expand our knowledge of telomerase and present new targets for the manipulation of telomerase function in human disease.