This thesis investigates the effect of Russian wheat aphid (RWA; Diuraphis noxia) infestation on the defence responses of the bread wheat line, PI 137739, on a molecular level. PI 137739 is known to contain the RWA resistance gene, Dn1. The study was conducted by utilising and combining a vast array of molecular biological techniques. Chapter 1 introduces the reader to a summary of the resistance responses observed within infested plants. A detailed description of the Russian wheat aphid follows and the genes responsible for RWA resistance in wheat is discussed. A brief report of research performed on the bread wheat genome is given and the biochemical defence responses of plants against insect infestation are discussed. This is followed by a concise description of resistance (R) genes and resistance gene categories in plants. The last discussion concerns microarray technology, a molecular tool utilised during this study. Chapter 2 aims at identifying genes involved in resistance against RWA infestation; specifically, genes containing the conserved nucleotide binding site¬leucine rich repeat (NBS-LRR) motif. Genomic, as well as complementary DNA (cDNA), was utilised in order to compare functional gene expression in wheat infested with the RWA. This was executed by employing PCR-based methods, single-pass sequencing and basic local alignment search tool (BLAST) analyses. Chapter 3 introduces suppression subtractive hybridisation (SSH) as a tool to further identify NBS-LRR or other resistance-related sequences in RWA infested wheat plants. SSH allows the comparative analysis of differential gene expression in RWA infested and uninfested wheat in order to identify resistance-¬related genes expressed in the infested, resistant wheat plants. The effect of RWA infestation on wheat resistance responses was examined further in chapter 4 through microarray analysis. The aim was the introduction and establishment of the microarray technique and to test the feasibility of using microarrays for differential gene expression and regulation studies. Microarray slides were assembled in order to monitor the up- and down¬regulation of genes at different time intervals - day 2, day 5 and day 8 - of RWA infestation. Clones isolated throughout this study were assembled on microarray slides and probed with control and RWA infested RNA. Differential gene regulation was assessed and further confirmed through Northern blot analyses, as well as quantitative real-time PCR. The thesis concludes with a general summary of the results obtained in chapter 5 and future prospects are outlined. / Thesis (PhD(Genetics))--University of Pretoria, 2005. / Genetics / unrestricted

Les éléments transposables (ETs) sont des séquences d'ADN mobiles retrouvées dans les génomes de toutes les espèces où ils ont été recherchés. Moteurs de l'évolution, ces éléments mobiles, présents en de nombreuses copies dans les génomes, ont joué un rôle majeur dans la dynamique des génomes en engendrant des mutations et des réarrangements chromosomiques.Néanmoins, étant des constituants majeurs des génomes, ils doivent être finement régulés dans le but de préserver l'intégrité génomique, et ainsi de conserver l'équilibre entre variabilité et stabilité des génomes. Afin de protéger l'information génétique de l'hôte transmise à la descendance, la régulation des ETs au niveau des gonades est effectuée par la voie des piRNAs, voie d'ARN interférent conservée chez les animaux. Bien qu'elle soit relativement bien décrite chez la drosophile et la souris, certaines étapes de cette voie restent encore incomprises. Durant ma thèse, j’ai exploré différents aspects de la biologie des clusters de piRNAs, en prenant comme modèle d’étude le locus flamenco. Le cluster de piRNAs flamenco est le producteur majeur de piRNAs dans les cellules folliculaires des ovaires de Drosophila melanogaster. Tout d'abord, j'ai analysé les fenêtres spatio-temporelles de l’expression du cluster de piRNAs flamenco tout au long du développement de la drosophile,de l'embryon à l'âge adulte. Ensuite, j'ai recherché, in vivo, la séquence des transcrits de flamenco qui serait suffisante pour induire l'adressage d'un transcrit chimérique à la voie de maturation des piRNAs. J'ai également exploré l'impact de certains facteurs sur la prise en charge de transcrits artificiels par la voie des piRNAs. Enfin, je me suis intéressée à la régulation génique que pourraient effectuer les piRNAs provenant de flamenco dans les ovaires de drosophile en recherchant, par des approches bioinformatiques et de biologie moléculaire, les gènes potentiellement reconnus, et par conséquent, régulés par les piRNAs de flamenco. L'ensemble de ces axes de recherche in vivo permettront d'avancer dans la compréhension de la biologie des clusters de piRNAs ainsi que sur les mécanismes moléculaires mis en jeu lors de la biogenèse des piRNAs chez la drosophile. / Transposable elements (TEs) are defined such as mobile DNA sequences found in genomes ofall species where they were searched. As evolutionary drivers, these mobile elements, presentin many copies in genomes, have played a major role in the genome dynamics by generatingmutations and chromosomal rearrangements. Nevertheless, being major genome constituents,they must be finely regulated in order to preserve the genomic integrity, and thus, to maintainthe balance between variability and stability of genomes. In order to protect the geneticinformation of the host transmitted to the offspring, the gonadal TE regulation is carried outby the piRNAs pathway, an interfering RNA pathway conserved in animals. Although this isrelatively well described in Drosophila and in mouse, some steps of piRNA pathway are stillmisunderstood. During my thesis, I explored various aspects of piRNA cluster biology, usingthe flamenco locus as a model. This piRNA cluster is the main piRNA producer in thefollicular cells of Drosophila melanogaster ovaries. First, I analyzed the spatio-temporalwindows of flamenco piRNA cluster expression throughout the Drosophila development,from embryo to adulthood. Then, I searched, in vivo, the flamenco transcript sequence thatwould be sufficient to induce the addressing of a chimeric transcript to the piRNA processingpathway. I also explored the impact of some factors on the management of artificialtranscripts by piRNAs. Finally, I was interested in the gene regulation that flamenco-derivedpiRNAs could make in Drosophila ovaries by searching, through bioinformatics andmolecular biology approaches, the potentially recognized genes, and therefore, regulated byflamenco piRNAs. All of these in vivo research axes will advance in the understanding of thebiology of piRNA clusters as well as the molecular mechanisms involved in the piRNAbiogenesis in Drosophila.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Alzheimer’s disease (AD) is a neurological disorder defined by the presence of plaques comprised mostly of amyloid-β (Aβ), and neurofibrillary tangles consisting of hyperphosphorylated microtubule associated protein tau (MAPT). AD is also characterized by widespread synapse loss and degeneration followed by death of neurons in the brain. Inflammatory processes, such as glial activation, are also implicated. In order to study mechanisms of neurodegeneration and evaluate potential therapeutic agents that could slow or reverse this process, a tissue culture system was developed based on primary embryonic cerebrocortical neurons. This culture system was observed to exhibit time-dependent neurodegeneration, glial proliferation, and synaptic marker loss consistent with AD-affected brains. The regulatory promoter regions of several genes implicated in AD, including the Aβ precursor protein (APP), β-amyloid cleaving enzyme (BACE1), and MAPT, were studied in this culture model. The MAPT gene promoter activity followed the pattern of neuronal maturation and degeneration quite closely, increasing in the initial phase of the tissue culture, then reducing markedly during neurodegeneration while APP and BACE1 gene promoters remained active. Deletion series of these promoters were tested to give an initial indication of the active regions of the gene promoter regions. Furthermore, the effects of exogenous Aβ and overexpression of p25, which are two possible pathogenic mechanisms of gene regulation in AD, were studied. Response to Aβ varied between the promoters and by length of the Aβ fragment used. Overexpression of p25 increased MAPT, but not APP or BACE1, promoter activity. This neurodegeneration model was also used to study the putative neuroprotective action of the NMDA receptor antagonist memantine. Treatment with memantine prevented loss of synaptic markers and preserved neuronal morphology, while having no apparent effect on glial activation. The protective action on synaptic markers was also observed with two other structurally distinct NMDA receptor antagonists, suggesting that the effects of memantine are produced by its action on the NMDA receptor. It is concluded that this tissue culture model will be useful for the study of gene regulation and therapeutic agents for neurodegeneration, and that the efficacy of memantine may result from preservation of synaptic connections in the brain.

Development of multicellular organisms is one of the most fundamental but least understood biological processes. Due to its simple life cycle, the lower eukaryote Dictyostelium has been used as a model system to study several basic biological problems, such as cell differentiation, cell motility, cell adhesion, signal transduction, and especially gene regulation. Glycogen phosphorylase is the enzyme that initiates one of the key biochemical pathways, glycogen degradation, during Dictyostelium discoideum development. Two forms of glycogen phosphorylase, gpl and gp2, exist in D. discoideum with gp1 being active in vegetative cells and gp2 in differentiating cells. Study of glycogen phosphorylase gene regulation clearly will provide insight into the molecular mechanism of D. discoideum development and facilitate understanding of development in general. Two distinct genes that encode the two forms of glycogen phosphorylase were cloned. The nucleotide sequence analysis of the gp2 gene revealed an open reading frame of 2976 bp, that consists of three exons separated by two introns. An interesting feature in the gene is a 45 bp sequence in the second exon that contains 11 CAA trinucleotide repeats. The entire 5' and 3' non-coding regions of the gp2 gene and the whole 5' noncoding region of the gp1 gene have also been cloned. The regulation of the gp2 gene by Dictyostelium developmental signals was studied. Both cyclic AMP (cAMP) and Differentiation Inducing Factor (DIF) were discovered to induce gp2 gene expression during differentiation. DIF was also found to inhibit the cAMP responsiveness of the gene. Both cAMP and DIF induction of the gene were repressed by NH₃. Another developmental signalling molecule, adenosine, was involved in gp2 gene regulation through the inhibition of the DIF-mediated expression. The cell-type-specificity of the gp2 gene were also investigated. The gene was found to be expressed in both prestalk/stalk and prespore/spore cells. This is in agreement with the cAMP and DIF inducibility of the gene since the former molecule is a spore-cell morphogen, while the latter is a stalk-cell morphogen. A model of gp2 gene regulation during development is proposed, based on these findings. The two gp? introns and the 45 bp CAA repeat were studied by deletion of these elements. However, there were no alterations of gp2 gene expression observed after these deletions. Also investigated was genomic structural alteration in gp1- mutants that were obtained through homologous recombination and antisense RNA. Southern analysis revealed that the normal gp1 gene was disrupted in all homologous recombination transformants and in half of the antisense RNA transformants. Finally, for the first time, an extrachromosomal luciferase reporter vector has been established for the study of cis-acting regulatory elements in D. discoideum. / Ph. D.

Dans le cadre de l’étude de la régulation de la synthèse de la cytokine pro-inflammatoire TNF-alpha dans les cellules myéloïdes stimulées aux lipopolysaccharides, nous avons pu mettre en évidence que l’effet anti-inflammatoire du nicotinamide (NAM) sur la production de cette cytokine s’opère au niveau de l’état de phosphorylation de la MAPK p38. Une diminution de la concentration intracellulaire de NAD entraine également une inhibition de la phosphorylation de la MAPK p38 en réponse aux lipopolysaccharides. De plus, une étude pharmacologique plus ciblée suggère que les sirtuines, une famille d’enzymes consommatrices de NAD, sont impliquées dans cette régulation. Nos résultats indiquent que ce processus s’effectuerait par un contrôle de l’expression des gènes mkp-1 et pac-1 codant pour des « dual-phosphatases » modulant l’état de phosphorylation des MAPKs. Enfin, nos données indiquent que l’effet anti-inflammatoire du NAM s’opère aussi par une régulation de l’efficacité traductionnelle du messager du TNF-alpha impliquant un raccourcissement de la queue poly(A) du messager. En conclusion, l’ensemble de nos données montre une complexité importante dans la régulation de la production de TNF-alpha dans les cellules myéloïdes par des enzymes consommatrices de NAD, dont les sirtuines. / Doctorat en sciences, Spécialisation biologie moléculaire / info:eu-repo/semantics/nonPublished

Cheung Hoi Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 151-166). / Abstracts in English and Chinese. / ACKNOWLEDGEMENT --- p.I / ABSTRACT --- p.II / ABBREVIATIONS --- p.IV / LIST OF FIGURES --- p.VII / LIST OF TABLES --- p.IX / CONTENTS --- p.X / Chapter CHAPTER ONE: --- GENERAL INTRODUCTION / Chapter 1.1 --- Non-coding RNAs in transcriptional output --- p.2 / Chapter 1.2 --- Diverse functions of non-coding RNAs --- p.5 / Chapter 1.3 --- HI9: imprinted non-coding RNA --- p.6 / Chapter 1.4 --- Objective --- p.7 / Chapter CHAPTER TWO: --- The ROLE OF H19 RNA IN MDR1 EXPRESSION OF HUMAN HEPATOCELLULAR CARCINOMA HepG2 CELLS / Chapter 2.1 --- Introduction / Chapter 2.1.1 --- H19-Igf2 locus as a model for genomic imprinting --- p.10 / Chapter 2.1.2 --- HI9 as a non-protein coding regulatory RNA --- p.12 / Chapter 2.1.3 --- Controversial roles of H19 RNA --- p.13 / Chapter 2.1.4 --- Novel role of H19 RNA in drug resistance --- p.15 / Chapter 2.2 --- Materials and methods / Chapter 2.2.1 --- Materials --- p.17 / Chapter 2.2.2 --- Methods / Chapter 2.2.2.1 --- Cell culture --- p.19 / Chapter 2.2.2.2 --- Plasmid construction and stable cell transfection --- p.19 / Chapter 2.2.2.3 --- Transient gene transfection --- p.20 / Chapter 2.2.2.4 --- RNA isolation and RT-PCR --- p.21 / Chapter 2.2.2.5 --- MTT drug sensitivity assay --- p.22 / Chapter 2.2.2.6 --- Western blot analysis --- p.22 / Chapter 2.3 --- Results / Chapter 2.3.1 --- Differential expression of H19 RNA in different human cancer cell lines --- p.24 / Chapter 2.3.2 --- R-HepG2 cells over-expressed P-glycoprotein and H19 RNA --- p.24 / Chapter 2.3.3 --- Development of H19-silenced cell lines in HepG2 cells by RNA interference --- p.26 / Chapter 2.3.4 --- Altered drug sensitivity in H19-silenced cells --- p.28 / Chapter 2.3.5 --- Expression of P-glycoprotein in H19-silenced cells --- p.31 / Chapter 2.3.6 --- Overexpression of H19 RNA in HepG2 cells --- p.34 / Chapter 2.3.7 --- Induction of H19 RNA and MDR1 in HepG2 cells --- p.34 / Chapter 2.4 --- Discussion / Chapter 2.4.1 --- H19 regulation of MDR1 associated drug resistance --- p.38 / Chapter 2.4.2 --- The puzzle of riboregulation in drug resistance --- p.40 / Chapter CHAPTER THREE: --- The ROLES OF PTB AND IMP1 IN H19-RELATED MDR1 EXPRESSION OF HUMAN HEPATOCELLULAR CARCINOMA HepG2 CELLS / Chapter 3.1 --- Introduction / Chapter 3.1.1 --- H19 RNA binding proteins --- p.43 / Chapter 3.2 --- Materials and methods / Chapter 3.2.1 --- Materials --- p.46 / Chapter 3.2.2 --- Methods / Chapter 3.2.2.1 --- Cell culture --- p.48 / Chapter 3.2.2.2 --- Plasmid construction and stable cell transfection --- p.48 / Chapter 3.2.2.3 --- RNA extraction and RT-PCR --- p.48 / Chapter 3.2.2.4 --- MTT drug sensitivity assay --- p.48 / Chapter 3.2.2.5 --- Western blot analysis --- p.48 / Chapter 3.2.2.6 --- Real-time PCR analysis of gene expression --- p.49 / Chapter 3.2.2.7 --- DOX efflux assay --- p.49 / Chapter 3.3 --- Results / Chapter 3.3.1 --- PTB knockdown increased P-glycoprotein expression --- p.51 / Chapter 3.3.2 --- IMP1 knockdown decreased MDR1 /P-glycoprotein expression --- p.54 / Chapter 3.3.3 --- Altered drug sensitivity in IMP 1 -knockdown cells --- p.60 / Chapter 3.4 --- Discussion / Chapter 3.4.1 --- Antagonistic effect of PTB and IMP1 on H19/MDR1 expressions --- p.64 / Chapter 3.4.2 --- Complexity of riboregulation --- p.65 / Chapter CHAPTER FOUR: --- IDENTIFICATION OF H19 RNA BINDING PROTEINS FROM HUMAN HEPATOCELLULAR CARCINOMA HepG2 CELLS / Chapter 4.1 --- Introduction / Chapter 4.1.1 --- Overview of RNA-protein interactions --- p.69 / Chapter 4.1.2 --- Methodology in the study of RNA-protein interactions --- p.71 / Chapter 4.1.3 --- Identification of RNA-binding proteins --- p.72 / Chapter 4.2 --- Materials and methods / Chapter 4.2.1 --- Materials --- p.75 / Chapter 4.2.2 --- Methods / Chapter 4.2.2.1 --- Screening of H19 cDNA from human placenta cDNA library --- p.78 / Chapter 4.2.2.2 --- Preparation of nuclear and cytoplasmic extracts from HepG2 cells / Chapter 4.2.2.3 --- In vitro RNA transcription and RNA labeling --- p.80 / Chapter 4.2.2.4 --- RNA electrophoretic mobility shift assay --- p.81 / Chapter 4.2.2.5 --- In vitro UV-crosslinking assay --- p.82 / Chapter 4.2.2.6 --- Preparation of RNA-affinity column and isolation of RNA binding proteins --- p.83 / Chapter 4.2.2.7 --- In-gel digestion and MALDI-TOF mass spectrometry --- p.84 / Chapter 4.3 --- Results / Chapter 4.3.1 --- Screening of H19 cDNA and preparation ofH19 RNA --- p.86 / Chapter 4.3.2 --- Electrophoretic mobility shift analysis of H19 RNA with HepG2 cytoplasmic extract --- p.87 / Chapter 4.3.3 --- UV-crosslinking of H19 RNA with HepG2 nuclear and cytoplasmic extract --- p.90 / Chapter 4.3.4 --- Isolation of H19 RNA binding proteins by RNA-affmity chromatography --- p.94 / Chapter 4.3.5 --- Confirmation of PTB and IMP1 as H19 RNA binding protein --- p.96 / Chapter 4.3.6 --- MALDI-TOF mass spectrometric analysis of isolated H19 RNA binding proteins --- p.96 / Chapter 4.4 --- Discussion / Chapter 4.4.1 --- RNA-protein interactions: an initial step for mechanistic study --- p.99 / Chapter 4.4.2 --- In vitro and in vivo methods for isolation of RNA binding proteins --- p.101 / Chapter 4.4.3 --- Novel role of hnRNP M protein in H19 RNA binding --- p.103 / Chapter CHAPTER FIVE: --- THE ROLE OF PTB IN APOPTOSIS / Chapter 5.1 --- Introduction / Chapter 5.1.1 --- Overview of polypyrimidine tract-binding protein in RNA processing and post-transcriptional gene regulation --- p.106 / Chapter 5.1.2 --- Evidences of polyrimidine-tract binding protein in the regulation of apoptosis --- p.108 / Chapter 5.2 --- Materials and methods / Chapter 5.2.1 --- Materials --- p.111 / Chapter 5.2.2 --- Methods / Chapter 5.2.2.1 --- Cell culture --- p.114 / Chapter 5.2.2.2 --- Stable cell transfection in A431 cells --- p.114 / Chapter 5.2.2.3 --- Western Blot analysis --- p.114 / Chapter 5.2.2.4 --- MTT drug sensitivity assay --- p.114 / Chapter 5.2.2.5 --- DNA fragmentation assay --- p.115 / Chapter 5.2.2.6 --- Flow cytometry analysis of apoptosis --- p.115 / Chapter 5.2.2.7 --- Caspase activity assay --- p.116 / Chapter 5.3 --- Results / Chapter 5.3.1 --- Taxol as an apoptosis inducer in HepG2 cells --- p.117 / Chapter 5.3.2 --- PTB was cleaved during Taxol-induced apoptosis --- p.118 / Chapter 5.3.3 --- PTB knockdown increased Taxol cytotoxicity and apoptosis --- p.118 / Chapter 5.3.4 --- Effect of PTB knockdown on drug sensitivity of cells --- p.121 / Chapter 5.3.5 --- Effect of PTB knockdown on other drug-induced apoptosis --- p.121 / Chapter 5.3.6 --- Effect of PTB knockdown on the basal expressions of genes in apoptosis pathway --- p.126 / Chapter 5.3.7 --- The role of caspase-9 activation in PTB-regulated apoptosis --- p.129 / Chapter 5.3.8 --- The effect of PTB knockdown on pro-caspase-9 expression and Taxol-induced apoptosis in A431 cells --- p.133 / Chapter 5.3.9 --- The role of PTB in the regulation of intrinsic apoptosis pathway --- p.136 / Chapter 5.4 --- Discussion / Chapter 5.4.1 --- The role of PTB in intrinsic apoptosis pathway --- p.138 / Chapter 5.4.2 --- PTB in regulation of pro-caspase-9 expression --- p.139 / Chapter CHAPTER SIX: --- GENERAL DISCUSSION AND CONCLUSION / Chapter 6.1 --- H19 as a potential target in anti-cancer gene therapy --- p.143 / Chapter 6.2 --- Conclusion --- p.144 / Chapter 6.3 --- Unanswered questions and future work --- p.145 / Chapter 6.4 --- A proposed model for H19 pathway --- p.148 / REFERENCES --- p.151

Gho Wai-Man. / Thesis submitted in: August 2006. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 114-123). / Abstracts in English and Chinese. / ABSTRACT --- p.I / 摘要 --- p.IV / ACKNOWLEDGEMENT --- p.VI / TABLE OF CONTENT --- p.VII / LIST OF TABLES --- p.XII / LIST OF FIGURES --- p.XIII / ABBREVIATIONS --- p.XVI / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Introduction --- p.2 / Chapter 1.2 --- Epidemiology --- p.2 / Chapter 1.3 --- Etiological factors --- p.6 / Chapter 1.3.1 --- Viral Hepatitis Infection --- p.6 / Chapter 1.3.1.1 --- Hepatitis B Virus (HBV) --- p.7 / Chapter 1.3.1.2 --- Hepatitis C Virus (HCV) --- p.9 / Chapter 1.3.2 --- Aflatoxin Exposure --- p.10 / Chapter 1.3.3 --- Alcohol Abuse --- p.11 / Chapter 1.3.4 --- Liver Cirrhosis --- p.12 / Chapter 1.4 --- Genetic alterations in hcc --- p.16 / Chapter 1.4.1 --- Chromosomal Gain --- p.16 / Chapter 1.4.2 --- Chromosomal Loss --- p.17 / Chapter 1.5 --- Discovery of common activating transcription factor 5 (atf5) down-regulations in hcc --- p.19 / Chapter 1.5.1 --- Chromosome 19 Aberration in HCC --- p.19 / Chapter 1.5.2 --- Discovery of High Frequency of　ATF5 Down-regulations --- p.19 / Chapter 1.5.3 --- Activating Transcription Factor Family --- p.20 / Chapter 1.6 --- Aim of thesis --- p.28 / Chapter CHAPTER 2 --- MATERIALS AND METHODS --- p.29 / Chapter 2.1 --- Materials --- p.30 / Chapter 2.1.1 --- Chemicals --- p.30 / Chapter 2.1.2 --- Buffers --- p.31 / Chapter 2.1.3 --- Cell culture --- p.31 / Chapter 2.1.4 --- Nucleic acids --- p.32 / Chapter 2.1.5 --- Enzymes --- p.32 / Chapter 2.1.6 --- Equipment --- p.32 / Chapter 2.1.7 --- Kits --- p.33 / Chapter 2.1.8 --- Software and Web Resource --- p.33 / Chapter 2.2 --- Dna extraction --- p.34 / Chapter 2.2.1 --- Cell Lines --- p.34 / Chapter 2.2.2 --- Primary HCC --- p.34 / Chapter 2.2.3 --- Lymphocytic DNA --- p.35 / Chapter 2.3 --- Rna extraction --- p.36 / Chapter 2.4 --- Dna sequencing --- p.38 / Chapter 2.4.1 --- Polymerase Chain Reaction (PCR) --- p.38 / Chapter 2.4.2 --- Cycle Sequencing --- p.39 / Chapter 2.5 --- Dual-labeled fluirescence in situ hybridization (fish) --- p.41 / Chapter 2.5.1 --- FISH Probe Preparation --- p.41 / Chapter 2.5.1.1 --- Preparation of Human Bacterial Artificial Chromosome (BAC) --- p.41 / Chapter 2.5.1.2 --- Nick Translation --- p.41 / Chapter 2.5.2 --- FISH --- p.42 / Chapter 2.6 --- 5-aza-2'-deoxycytidine & trichostatin a treatment on cell lines --- p.43 / Chapter 2.7 --- Bisulfite modificaiton of dna --- p.43 / Chapter 2.8 --- Methylation-specific pcr (msp) --- p.44 / Chapter 2.9 --- Bisulfite dna sequencing --- p.44 / Chapter 2.10 --- Quantitative reverse transcription pcr (qrt-pcr) --- p.46 / Chapter 2.11 --- In-vitro and in-vivo functinal examination --- p.49 / Chapter 2.11.1 --- ATF5 Transfection --- p.49 / Chapter 2.11.2 --- Cell Growth Assay --- p.50 / Chapter 2.11.3 --- Xenograft Development --- p.51 / Chapter 2.12 --- codelink expression microarray --- p.51 / Chapter 2.13 --- Statistical analysis --- p.53 / Chapter CHAPTER 3 --- INACTIVATION OF MECHANISMS UNDERLYING ATF5 DOWN-REGULATION --- p.54 / Chapter 3.1 --- Introduction --- p.55 / Chapter 3.2 --- Materials and methods --- p.58 / Chapter 3.2.1 --- Cell Lines --- p.58 / Chapter 3.2.2 --- Mutational Analysis --- p.58 / Chapter 3.2.3 --- Copy Number Loss --- p.59 / Chapter 3.2.4 --- Epigenetic Control --- p.59 / Chapter 3.3 --- Results --- p.67 / Chapter 3.3.1 --- Sequencing Analysis of A TF5 Gene --- p.67 / Chapter 3.3.2 --- FISH Analysis of ATF5 Copy Number --- p.73 / Chapter 3.3.3 --- Epigenetic Control of A TF5 Expression --- p.73 / Chapter 3.4 --- Discussion --- p.82 / Chapter CHAPTER 4 --- FUNCTIONAL EXAMINATION AND INVESTIGATION OF DOWNSTREAM TARGETS MODULATED BY ATF5 --- p.85 / Chapter 4.1 --- Introduction --- p.86 / Chapter 4.2 --- Materials and methods --- p.88 / Chapter 4.2.1 --- Cell Lines --- p.88 / Chapter 4.2.2 --- Plasmids and Transfection --- p.88 / Chapter 4.2.3 --- Cell Growth Assay --- p.88 / Chapter 4.2.4 --- Xenograft Development --- p.88 / Chapter 4.2.5 --- CodeLink Expression Microarray --- p.89 / Chapter 4.2.6 --- Quantitative RT-PCR --- p.90 / Chapter 4.2.7 --- Statistical analysis --- p.90 / Chapter 4.3 --- Results --- p.91 / Chapter 4.3.1 --- Cell Proliferation --- p.91 / Chapter 4.3.1.1 --- In-Vitro Examination --- p.91 / Chapter 4.3.1.2 --- In-Vivo Examination --- p.91 / Chapter 4.3.2 --- Microarray A nalysis --- p.91 / Chapter 4.3.3 --- Correlation of A TF5 with Id-1 Expression --- p.103 / Chapter 4.4 --- Discussion --- p.106 / Chapter CHAPTER 5 --- PROPOSED FUTURE INVESTIGATIONS --- p.110 / Chapter 5.1 --- inactivation mechanisms of atf5 gene --- p.111 / Chapter 5.2 --- Molecular pathways modulated by atf5 --- p.112 / Chapter CHAPTER 6 --- REFERENCES --- p.114

Choi Wai-wah. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 120-138). / Abstracts in English and Chinese. / Statement --- p.i / Acknowledgements --- p.ii / Abstract --- p.iii / Abstract (Chinese Version) --- p.v / Table of Contents --- p.vii / List of Tables --- p.xii / List of Figures --- p.xiii / List of Abbreviations --- p.xv / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- "Hemoglobin ´ؤ Structures, Types and Functions" --- p.1 / Chapter 1.1.1 --- Structures of Hemoglobin --- p.1 / Chapter 1.1.2 --- Types of Hemoglobin --- p.2 / Chapter 1.1.3 --- Functions of Hemoglobin --- p.3 / Chapter 1.2 --- Human Globin Genes and Their Regulation --- p.5 / Chapter 1.2.1 --- Organization of the Human Globin Genes --- p.5 / Chapter 1.2.2 --- Regulation of Globin Gene Expression --- p.6 / Chapter 1.2.2.1 --- The Locus Control Region (LCR) --- p.6 / Chapter 1.2.2.2 --- Cis-Regulatory Elements --- p.7 / Chapter 1.2.2.2.1 --- Promoters --- p.7 / Chapter 1.2.2.2.2 --- Enhancers --- p.7 / Chapter 1.2.2.2.3 --- Silencers --- p.8 / Chapter 1.2.2.3 --- Trans-Acting Factors --- p.8 / Chapter 1.2.2.3.1 --- GATA Family --- p.9 / Chapter 1.2.2.3.2 --- Kruppel-like Factors --- p.9 / Chapter 1.2.2.3.3 --- Nuclear Factor-Erythroid (NF-E) --- p.9 / Chapter 1.2.2.4 --- Chromatin Remodelling --- p.10 / Chapter 1.2.2.5 --- Intergenic Sequences --- p.11 / Chapter 1.3 --- Mechanisms of Hemoglobin Switching --- p.12 / Chapter 1.3.1 --- Autonomous Silencing --- p.12 / Chapter 1.3.2 --- LCR and Globin Gene Interaction --- p.12 / Chapter 1.4 --- Hemoglobinopathies --- p.14 / Chapter 1.4.1 --- α -thalassemia --- p.14 / Chapter 1.4.2 --- β -thalassemia --- p.14 / Chapter 1.4.3 --- Sickle Cell Anemia --- p.16 / Chapter 1.5 --- Therapies for β-thalassemia --- p.16 / Chapter 1.5.1 --- Blood Transfusion --- p.16 / Chapter 1.5.2 --- Bone Marrow Transplantation --- p.17 / Chapter 1.5.3. --- Gene Therapy --- p.17 / Chapter 1.6 --- Gene Switch Therapy --- p.18 / Chapter "1.6,1" --- Pharmacological Induction of HbF --- p.18 / Chapter 1.6.1.1 --- Hydroxyurea --- p.19 / Chapter 1.6.1.2 --- Butyrate --- p.20 / Chapter 1.6.1.3 --- Summary --- p.21 / Chapter 1.7 --- Objectives --- p.22 / Chapter Chapter 2 --- Induction of HbF by LC978 in K562 / Chapter 2.1 --- Introduction --- p.23 / Chapter 2.2 --- Materials --- p.26 / Chapter 2.2.1 --- Chemicals and Reagents --- p.26 / Chapter 2.2.2 --- Kits --- p.27 / Chapter 2.2.3 --- Buffers and Solutions --- p.27 / Chapter 2.2.4 --- Primers --- p.30 / Chapter 2.2.5 --- Equipment and Other Consumables --- p.30 / Chapter 2.2.6 --- Maintenance of K562 --- p.31 / Chapter 2.2.7 --- Handling and Treatment of utilities for RNA isolation --- p.31 / Chapter 2.3 --- Methods --- p.32 / Chapter 2.3.1 --- Dose-response and time-response study of LC978 in K562 by TMB assay --- p.32 / Chapter 2.3.2 --- Detection of γ -Globin Gene Expression in LC978-induced K562 by RT-PCR --- p.33 / Chapter 2.3.3 --- Fetal Hemoglobin Analysis by Human Fetal Hemoglobin (HbF) ELISA Quantitation Kit --- p.36 / Chapter 2.3.4 --- Statistical Analysis --- p.38 / Chapter 2.4 --- Results --- p.39 / Chapter 2.4.1 --- Dose-response and time-response study of LC978 in K562 by TMB assay --- p.39 / Chapter 2.4.2 --- Detection of γ -Globin Gene Expression in LC978-induced K562 by RT-PCR --- p.45 / Chapter 2.4.3 --- Fetal Hemoglobin Analysis by Human Fetal Hemoglobin (HbF) ELISA Quantitation Kit --- p.48 / Chapter 2.5 --- Discussions --- p.51 / Chapter Chapter 3 --- Signal Transduction Pathways Modulated by LC978 / Chapter 3.1 --- Introduction --- p.54 / Chapter 3.2 --- Materials --- p.57 / Chapter 3.2.1 --- Chemicals and Reagents --- p.57 / Chapter 3.2.2 --- Kits --- p.57 / Chapter 3.2.3 --- Buffers and Solutions --- p.58 / Chapter 3.2.4 --- Primers --- p.59 / Chapter 3.2.5 --- Equipment and Other Consumables --- p.60 / Chapter 3.2.6 --- Maintenance of K562 --- p.60 / Chapter 3.2.7 --- Handling and Treatment of utilities for RNA isolation --- p.60 / Chapter 3.3 --- Methods --- p.61 / Chapter 3.3.1 --- Identification of Signaling Pathways by Microarray --- p.61 / Chapter 3.3.2 --- Real-time RT-PCR --- p.65 / Chapter 3.4 --- Results --- p.67 / Chapter 3.4.1 --- Identification of Signaling Pathways by Microarray --- p.67 / Chapter 3.4.2 --- Real-time RT-PCR --- p.74 / Chapter 3.5 --- Discussions --- p.80 / Chapter Chapter 4 --- MAPK pathways and HbF induction by LC978 / Chapter 4.1 --- Introduction --- p.84 / Chapter 4.2 --- Materials --- p.87 / Chapter 4.2.1 --- Chemicals and Reagents --- p.87 / Chapter 4.2.2 --- Kits --- p.88 / Chapter 4.2.3 --- Buffers and Solutions --- p.88 / Chapter 4.2.4 --- Equipment and Other Consumables --- p.90 / Chapter 4.2.5 --- Maintenance of K562 --- p.90 / Chapter 4.3 --- Methods --- p.91 / Chapter 4.3.1 --- "Roles of three MAPKs ´ؤ ERK, JNK and p38 in LC978-mediated γ -globin gene induction in K562 using CASE´ёØ Kits" --- p.91 / Chapter 4.3.2 --- Effect of p38 inhibitor SB203580 on HbF induction --- p.94 / Chapter 4.3.3 --- Statistical Analysis --- p.97 / Chapter 4.4 --- Results --- p.98 / Chapter 4.4.1 --- "Roles of three MAPKs - ERK, JNK and p38 in LC978-mediated γ -globin gene induction in K562 using CASETM Kits" --- p.98 / Chapter 4.4.2 --- Effect of p38 inhibitor SB203580 on HbF induction --- p.106 / Chapter 4.5 --- Discussions --- p.110 / Chapter Chapter 5 --- Summary and Prospects / Appendix / References

Glicose e oxigênio são moléculas essenciais para a maioria dos organismos vivos. Além de sua importância nos processos de produção de energia - glicose como fonte de carbono e energia e oxigênio como aceptor dos elétrons doados por NADH e FADH2 - estes dois compostos funcionam como efetuadores, modulando vários processos metabólicos e fisiológicos nas células. Visto que a mitocôndria é um dos alvos afetados pelas disponibilidades destas duas moléculas, nós isolamos e seqüenciamos o genoma mitocondrial de Trichoderma reesei, um fungo multicelular empregado neste trabalho como sistema modelo. Foi estudado o efeito da variação de concentração de glicose e oxigênio sobre a expressão de transcritos do genoma mitocondrial, bem como sua implicação no metabolismo de glicose. São apresentadas análises da expressão gênica de aproximadamente 2000 transcritos de T. reesei submetido a concentrações limitantes de oxigênio dissolvido, realizadas com o emprego da técnica de microarrays de cDNA. Pelo menos 330 transcritos foram diferencialmente expressos em função da disponibilidade de oxigênio. Aqueles envolvidos nos processos de síntese protéica e divisão celular foram regulados negativamente, enquanto transcritos relacionados com funções de defesa celular e síntese de RNA foram positivamente regulados. Uma fração substancial de outros genes afetados pela baixa disponibilidade de oxigênio não possui, atualmente, funções celulares conhecidas. Esta observação deve contribuir para a posterior anotação funcional do genoma de T. reesei. Também foram identificados reguladores transcricionais diferencialmente expressos em baixas tensões de oxigênio. O perfil de expressão destes reguladores aponta-os como potenciais candidatos ao envolvimento com a expressão de genes afetados pela disponibilidade de oxigênio. / Glucose and oxygen are essential molecules in most of living organisms. In addition to their importance in production of energy - glucose as a carbon and energy source and oxygen as an acceptor of electrons donated by NADH and FADH2 - both molecules function as effectors modulating various metabolic and physiological processes in the cell. Because one of the targets affected by both molecules is the mitochondrion, we isolated and sequenced the mitochondrial genome of Trichoderma reesei, a multicellular fungus that is used in this study as a model system. The effect of varying the concentration of glucose and oxygen on the expression of the transcripts of the mitochondrial genome, and its implication on the metabolism of glucose, was studied. Gene-wide expression analyses of nearly 2000 transcripts of T. reesei under limited concentration of dissolved oxygen, using cDNA microarry technique, are presented. At least 330 transcripts were differentially expressed with respect to oxygen availability. Those involved in protein synthesis and cell division processes were downregulated, while transcripts involved in cell defense and RNA synthesis were upregulated. A substantive fraction of other anaerobically affected genes have currently unknown cellular roles, and these results should therefore contribute to further functional annotation of the genome. ln addition, we have identified transcriptional regulators that are differentially expressed at a low oxygen tensions. The expression profile of these regulators points them out as potential candidates involved in the expression of genes affected by oxygen availability.