Abstract not available

Bibliography: leaves 103-116. / vi, 116 leaves, [6] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Addresses the practical aspects of using nuclear transfer for the production of identical animals. Results from experiments provide improved understanding of the technical constraints of nuclear transfer. Also the flexibility of the methodology was increased with the use of in vitro culture and/or in vitro matured oocytes. / Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1992

Thesis (M.A.)--University of Delaware, 2008. / Principal faculty advisor: Jeffrey B. Rosen, Dept. of Psychology. Includes bibliographical references.

No description available.

No description available.

多聚谷氨酰胺疾病 (Polyglutamine diseases) 是一類在各自的致病基因編碼區的CAG重複編碼擴張造成的顯性遺傳神經退退化疾病。已擴大的CAG訊息核醣核酸 (Expanded CAG transcripts) 在多聚谷氨酰胺蛋白疾病作出細胞毒性作用。從基因減弱篩查中，我發現U2AF50能修飾已擴大的CAG訊息核醣核酸的毒性。並發現U2AF50能與已擴大的CAG訊息核醣核酸作實體互動，能參與已擴大的CAG訊息核醣核酸的核出口 (Nuclear export)。U2AF50的基因減弱增強已擴大CAG訊息核醣核酸在細胞核的累積和毒性。這突出核醣核酸的核出口在多聚谷氨酰胺疾病的重要性，並暗示細胞核是已擴大的CAG訊息核醣核酸毒性的起源地。此外，我鑑定已擴大的CAG訊息核醣核酸在亞細胞的分佈，並發現它們特別累積在核仁 (Nucleolus) 內。核仁是核糖體核醣核酸（rRNA）的轉錄場所。我發現已擴大的CAG訊息核醣核酸減弱rRNA基因啟動子 (rRNA promoter) 的活性並且抑制核糖體核醣核酸的轉錄。 核糖體核醣核酸基因轉錄的抑制，促進核糖體蛋白RpL23和E3連接酶MDM2蛋白作實體互動，從而增強p53的穩定性導。穩定的p53能夠轉移至線粒體 (Mitochondria)。我還發現，線粒體內的p53能打亂Bcl-xL與 Bak的實體互動，導致細胞色素C釋放到細胞質，這導致凋亡蛋白酶 (Caspases) 的活化和細胞凋亡。我的研究，首次證明核仁參與在多聚谷氨酰胺疾病的發病機制中，揭示了在多聚谷氨酰胺疾病中的新致病機制。 / Polyglutamine (polyQ) diseases are a class of dominantly inherited neurodegenerative disorders caused by the expansion of CAG-repeat encoding glutamine within the coding region of the respective disease genes. Expanded CAG transcripts have been reported to contribute to cytotoxicity in polyQ diseases. From a candidate gene knockdown screen, I identified U2AF50 as a modifier of RNA toxicity. U2AF50 has been reported to be involved in RNA nuclear export, and I showed that it interacted specifically with expanded CAG transcripts. Knockdown of U2AF50 expression enhanced nuclear accumulation of expanded CAG transcripts and neurotoxicity. This part of my work highlights the role of RNA nuclear export in polyQ degeneration and implies that the nucleus is a major site for RNA toxicity. In addition, I determined the subcellular distribution of expanded CAG transcripts and found that they particularly localized in the nucleolus. The nucleolus is a critical sub-nuclear compartment for ribosomal RNA (rRNA) transcription. I discovered that expanded CAG transcripts in nucleolus inhibited rRNA transcription by inactivating the rRNA gene promoter activity. Inhibition of rRNA transcription promoted the interaction between ribosomal protein L23 and the ubiquitin E3 ligase MDM2, which led to the stabilization of p53 and its accumulation in mitochondria. I also found that mitochondrial p53 disrupted the interaction between the anti-apoptotic protein, Bcl-xL, and pro-apoptotic protein, Bak, subsequently causing Cytochrome c release, caspase activation, and apoptosis. In summary, my study first describes the involvement of nucleolar function in polyQ pathogenesis and uncovers a new pathogenic mechanism in polyQ diseases. / Detailed summary in vernacular field only. / Tsoi, Ho. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 220-228). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Thesis Committee --- p.ii / Declaration --- p.iii / Acknowledgement --- p.iv / Abstract --- p.v / Abstract in Chinese --- p.vii / List of Abbreviations --- p.viii / List of Figures --- p.x / List of Tables --- p.xvi / Table of Contents --- p.xvi / Chapter 1 --- Introduction / Chapter 1.1 --- Introduction to Polyglutamine Diseases --- p.1 / Chapter 1.1.1 --- Etiology of Polyglutamine Diseases --- p.1 / Chapter 1.1.2 --- Common Features of Different Types of Polyglutamine Disease --- p.1 / Chapter 1.2 --- Pathogenic Mechanisms of Expanded Polyglutamine Proteins --- p.4 / Chapter 1.2.1 --- Pathogenesis of Polyglutamine Diseases --- p.4 / Chapter 1.2.1.1 --- Loss-of-function toxicity --- p.4 / Chapter 1.2.1.2 --- Gain-of-function toxicity --- p.4 / Chapter 1.3 --- Expanded CAG Transcript-mediated Pathogenic Mechanism --- p.6 / Chapter 1.3.1 --- Identification of the Toxic Role of Expanded CAG Transcripts --- p.6 / Chapter 1.3.2 --- Nuclear Foci Formation of Expanded CAG Transcripts and Polyglutamine Pathogenesis --- p.8 / Chapter 1.4 --- Receptor-mediated RNA nuclear export Transport --- p.9 / Chapter 1.4.1 --- Introduction to RNA Nuclear Export --- p.9 / Chapter 1.4.2 --- Regulation of RNA Nucleocytoplasmic Transport and Human Diseases --- p.11 / Chapter 1.5 --- Function of Nucleolus --- p.12 / Chapter 1.5.1 --- Ribosomal RNA Transcription --- p.12 / Chapter 1.5.2 --- Nucleolar Stress and Apoptosis --- p.15 / Chapter 1.6 --- Research Plan --- p.17 / Chapter 1.6.1 --- Project Objective --- p.17 / Chapter 1.6.2 --- Experimental Model --- p.17 / Chapter 1.6.2.1 --- In vivo Drosophila Model --- p.17 / Chapter 1.6.2.2 --- In vitro Cell Culture Model --- p.19 / Chapter 1.6.2.3 --- Transgenic Mouse Model --- p.20 / Chapter 1.6.3 --- Significance of the Present Study --- p.21 / Chapter 2 --- Materials and Methods / Chapter 2.1 --- Molecular Cloning --- p.22 / Chapter 2.1.1 --- Polymerase Chain Reaction (PCR) --- p.22 / Chapter 2.1.2 --- Primers Used for PCR --- p.29 / Chapter 2.1.3 --- Restriction Digestion --- p.31 / Chapter 2.1.4 --- Agarose Gel Electrophoresis --- p.32 / Chapter 2.1.5 --- Preparation of genomic DNA from A Single Adult Fly --- p.34 / Chapter 2.1.6 --- Removal of 5' Phosphate Groups on Linearized Plasmids --- p.35 / Chapter 2.1.7 --- Addition of 5' Phosphate Group to Linker Oligonucleotides --- p.35 / Chapter 2.1.8 --- Ligation Reaction --- p.37 / Chapter 2.1.9 --- Bacterial Transformation --- p.37 / Chapter 2.2 --- Mammalian Cell Culture --- p.40 / Chapter 2.3 --- Drosophila Culture --- p.44 / Chapter 2.4 --- Semi-quantitative Reverse Transcription-Polymerase Chain Reaction (RT-PCR) --- p.48 / Chapter 2.5 --- Microscopy --- p.51 / Chapter 2.6 --- Protein Sample Preparation and Concentration Measurement --- p.53 / Chapter 2.7 --- Co-immunoprecipitation --- p.57 / Chapter 2.8 --- Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Immunoblotting --- p.62 / Chapter 2.9 --- Bacterial Protein Purification --- p.65 / Chapter 2.1 --- DNA Methylation Assay --- p.68 / Chapter 2.11 --- Mitochondrial Fraction Isolation --- p.79 / Chapter 3 --- U2 Small Nuclear Riboprotein Auxiliary Factor 50 Modulates Polyglutamine Diseases Toxicity by Altering the Subcellular Localization of Expanded CAG Transcripts in vivo / Chapter 3.1 --- The Nuclear Accumulation of Expanded CAG Transcripts Correlates with the Neurodegeneration in vivo --- p.72 / Chapter 3.1.1 --- Expanded CAG Transcripts Predominantly Localize in the Nucleus in Drosophila Model of Machado-Joseph Disease --- p.72 / Chapter 3.1.2 --- Nuclear Accumulation of Expanded CAG Transcripts Correlates with the Neurodegeneration in an Inducible Model of Machado-Joseph Disease --- p.73 / Chapter 3.1.3 --- Nuclear Accumulation of Expanded CAG Transcripts Correlates with the Neurodegeneration in Inducible DsRed[subscript CAG100] Model. --- p.76 / Chapter 3.1.3.1 --- Expanded CAG Transcripts Induce the Expression of Pro-apoptotic Genes --- p.77 / Chapter 3.1.3.2 --- Co-expression of p35 Suppresses the Toxicity Induced by the Expanded CAG Transcripts --- p.80 / Chapter 3.2 --- A Candidate-gene RNA Interference Approach was Employed to Identify Genetic Factors Involved in Nuclear Export of Expanded CAG Transcripts --- p.80 / Chapter 3.3 --- Confirmation of the Modulatory Effect of U2 Small Nuclear Riboprotein Auxiliary Factor 50 on Machado-Joseph Disease in vivo --- p.84 / Chapter 3.4 --- The Modulatory Effect of U2 Small Nuclear Riboprotein Auxiliary Factor 50 on Different Drosophila Models of Polygultamine Diseases --- p.84 / Chapter 3.5 --- U2 Small Nuclear Riboprotein Auxiliary Factor 50 Specifically Modulates Expanded CAG Transcript-induced Toxicity in vivo --- p.87 / Chapter 3.5.1 --- Knockdown of U2 Small Nuclear Riboprotein Auxiliary Factor 50 Enhances Expanded CAG Transcript-induced Toxicity --- p.87 / Chapter 3.5.2 --- Knockdown of U2 Small Nuclear Riboprotein Auxiliary Factor 50 Does Not Modulate Expanded PolyQ Protein-induced Toxicity --- p.89 / Chapter 3.5.3 --- Knockdown of U2 Small Nuclear Riboprotein Auxiliary Factor 50 Does Not Alter the Expression Level of Expanded CAG Transcripts in vivo --- p.89 / Chapter 3.5.4 --- Knockdown of U2 Small Nuclear Riboprotein Auxiliary Factor 50 Does Not Modulate the Toxicity in Fragile X syndrome in vivo --- p.91 / Chapter 3.6 --- Over-expression of Human U2 Small Nuclear Riboprotein Auxiliary Factor 65 Does Not Modulate Expanded CAG Transcript-induced Toxicity in Drosophila --- p.91 / Chapter 3.7 --- Expanded CAG Transcripts Does Not Compromise Endogenous Function of U2 Small Nuclear Riboprotein Auxiliary Factor 50 --- p.94 / Chapter 3.8 --- A Correlation between Nucleocytoplasmic Localization of Expanded CAG Transcripts and Its Induced Toxicity --- p.97 / Chapter 3.8.1 --- Knockdown of U2 Small Nuclear Riboprotein Auxiliary Factor 50 Enriched DsRedCAG100 Transcripts in the Nucleus in vivo --- p.99 / Chapter 3.8.2 --- Knockdown of U2 Small Nuclear Riboprotein Auxiliary Factor 50 Enriched MJDCAG78 Transcripts in the Nucleus in vivo --- p.99 / Chapter 3.9 --- Expanded CAG-repeat on the Transcripts Interact with U2 Small Nuclear Riboprotein Auxiliary Factor 50/65 in vivo and in vitro --- p.102 / Chapter 3.9.1 --- Expanded CAG Transcripts Interact with U2 Small Nuclear Riboprotein Auxiliary Factor 50 in vivo --- p.102 / Chapter 3.9.2 --- Expanded CAG Transcripts Interact with U2 Small Nuclear Riboprotein Auxiliary Factor 65 in vitro --- p.103 / Chapter 3.9.3 --- Expanded CAG Transcripts Directly Interact with U2 Small Nuclear Riboprotein Auxiliary Factor 65 in vitro --- p.103 / Chapter 3.10 --- Identification of Expanded CAG Transcripts Interacting Domain on U2 Small Nuclear Riboprotein Auxiliary Factor 65 --- p.107 / Chapter 3.10.1 --- Generation of Different Myc-tagged U2 Small Nuclear Riboprotein Auxiliary Factor 65 Expression Constructs --- p.107 / Chapter 3.10.2 --- RNA Recognition Motif 3 on U2 Small Nuclear Riboprotein Auxiliary Factor 65 Is Essential for the Interaction with Expanded CAG Transcripts --- p.109 / Chapter 3.11 --- Nuclear RNA Export Factor 1 is Involved in U2 Small Nuclear Riboprotein Auxiliary Factor 65-mediated Nuclear Export of Expanded CAG Transcripts --- p.113 / Chapter 3.11.1 --- The Effect of Full Length U2 Small Nuclear Riboprotein Auxiliary Factor 65 and its Corresponding Deletion Mutants on Nuclear Export of Expanded CAG Transcripts --- p.113 / Chapter 3.11.2 --- Formation of Complexes Composed of Nuclear RNA Export Factor 1/U2 Small Nuclear Riboprotein Auxiliary Factor 65/Expanded CAG Transcripts in HEK293 Cells --- p.115 / Chapter 3.12 --- The Nuclear Export of Expanded CAG Transcripts is Mediated by U2 Small Nuclear Riboprotein Auxiliary Factor 65 and Nuclear RNA Export Factor 1 --- p.120 / Chapter 3.13 --- Aging Compromises the Nuclear Export of Expanded CAG Transcripts in Polyglutamine Disease Mouse Model --- p.123 / Chapter 3.13.1 --- Expanded CAG Transcripts Accumulate in the Nucleus of Polyglutamine Disease Mouse Model --- p.123 / Chapter 3.13.2 --- Expression Level of U2 Small Nuclear Riboprotein Auxiliary Factor 65 Declines with Age in Mice --- p.124 / Chapter 3.14 --- Discussion --- p.127 / Chapter 3.14.1 --- Expanded CAG Transcripts Induce Nuclear Toxicity through a Mechanism Independent on Pathogenic Mechanism Mediated by Other Trinucleotide Repeats Expansion --- p.127 / Chapter 3.14.2 --- Nuclear Accumulation of Expanded CAG Transcripts Leads to Neurodegeneration --- p.128 / Chapter 3.14.3 --- U2 Small Nuclear Riboprotein Auxiliary Factor 50 Modulates Expanded CAG Transcript-induced Toxicity by Mediating the Subcellular Localization of Expanded CAG Transcripts --- p.129 / Chapter 3.14.4 --- U2 Small Nuclear Riboprotein Auxiliary Factor 65 and Nuclear RNA Export Factor 1 Regulate the Nuclear Export of Expanded CAG Transcripts --- p.130 / Chapter 3.14.4.1 --- U2 Small Nuclear Riboprotein Auxiliary Factor 50/65 Interacts with Expanded CAG Transcripts and Mediates the Subcellular localization of Expanded CAG Transcripts --- p.130 / Chapter 3.14.4.2 --- U2 Small Nuclear Riboprotein Auxiliary Factor 65 Requires Nuclear RNA Export Factor 1 to Mediate the Nuclear Export of Expanded CAG Transcripts --- p.131 / Chapter 3.14.4.3 --- Developmental Decline of U2 Small Nuclear Riboprotein Auxiliary Factor 65 Protein Level is a Factor That Leads to Progressive Neurodegeneration in Polyglutamine Diseases --- p.134 / Chapter 4 --- Expanded CAG Transcripts Induce Nucleolar Stress / Chapter 4.1 --- Expanded CAG-repeat Sequence Mediates the Nucleolar Localization of RNA Transcripts in vitro --- p.135 / Chapter 4.1.1 --- Machado-Joseph Disease Cell Model --- p.135 / Chapter 4.1.2 --- EGFPCAG Cell Model --- p.137 / Chapter 4.2 --- Expanded CAG Transcripts Suppress Nucleolar Function in vitro and in vivo --- p.140 / Chapter 4.2.1 --- Expanded CAG Transcripts Suppress Ribosomal RNA Transcription in vivo --- p.140 / Chapter 4.2.1.1 --- Drosophila Model of Machado-Joseph Disease --- p.140 / Chapter 4.2.1.2 --- Drosophila Model of DsRedCAG --- p.142 / Chapter 4.2.1.3 --- Transgenic Mouse Model of PolyQ Disease --- p.142 / Chapter 4.2.2 --- Expanded CAG Transcripts Suppress rRNA Transcription in vitro --- p.145 / Chapter 4.2.2.1 --- Machado-Joseph Disease Patient-derived Fibroblast Cell Lines --- p.145 / Chapter 4.2.2.2 --- Expanded CAG Transcript-expressing HEK293 Cells --- p.145 / Chapter 4.3 --- Expanded CAG Transcripts Disrupt the Interaction between RNA Polymerase I and rRNA Promoter in vitro --- p.148 / Chapter 4.4 --- Expanded CAG Transcripts Disrupt the Interaction between Upstream Binding Factor and Upstream Control Element in vitro and in vivo --- p.149 / Chapter 4.4.1 --- Expanded CAG Transcripts Compromise the Interaction between Upstream Binding Factor and Upstream Control Element in vitro --- p.149 / Chapter 4.4.2 --- Expanded CAG Transcripts Compromise the Interaction between Upstream Binding Factor and Upstream Control Element in vivo --- p.151 / Chapter 4.5 --- Expanded CAG Transcripts Induce DNA Hyper-methylation on Upstream Control Element in vitro and in vivo --- p.151 / Chapter 4.5.1 --- The HpaII-PCR Assay for DNA Methylation --- p.154 / Chapter 4.5.2 --- Expanded CAG Transcripts Lead to DNA Hyper-methylation of Upstream Control Element in vitro --- p.154 / Chapter 4.5.2.1 --- Expanded CAG Transcript-expressing HEK293 Cells --- p.154 / Chapter 4.5.2.2 --- Machado-Joseph Disease Patient-derived Fibroblast Cell Lines --- p.156 / Chapter 4.5.3 --- Expanded CAG Transcripts Lead to DNA Hyper-methylation of Upstream Control Element in vivo --- p.156 / Chapter 4.5.4 --- Expanded CAG Transcripts Disrupt the Regulatory Mechanism of Upstream Control Element Methylation in vitro --- p.159 / Chapter 4.6 --- Expanded CAG Transcripts Induce Nucleolar Stress and Apoptosis --- p.161 / Chapter 4.6.1 --- Expanded CAG Transcripts Induce Nucleolar Stress in vitro and in vivo --- p.162 / Chapter 4.6.1.1 --- Expanded CAG Transcript-expressing HEK293 Cells --- p.162 / Chapter 4.6.1.2 --- Transgenic Mouse Model of PolyQ Disease --- p.162 / Chapter 4.6.2 --- Expanded CAG Transcripts Lead to Stabilization of p53 in vitro and in vivo --- p.165 / Chapter 4.6.2.1 --- Expanded CAG Transcripts Lead to Stabilization of p53 in vitro --- p.165 / Chapter 4.6.2.2 --- Expanded CAG Transcripts Lead to Stabilization of p53 in vivo --- p.167 / Chapter 4.6.3 --- Expanded CAG Transcripts Enrich p53 in Mitochondria in vitro --- p.167 / Chapter 4.6.4 --- Expanded CAG Transcripts Lead to Disruption of interaction between Bcl-xL and Bak by p53 in mitochondria in vitro --- p.169 / Chapter 4.6.5 --- Expanded CAG Transcripts Lead to Release of Cytochrome c in vitro --- p.171 / Chapter 4.6.6 --- Expanded CAG Transcripts Lead to Activation of Caspase 3 in vitro --- p.173 / Chapter 4.7 --- Discussion --- p.176 / Chapter 4.7.1 --- Expanded CAG Transcripts Compromise Nucleolar Function --- p.176 / Chapter 4.7.2 --- Expanded CAG Transcripts Induce Apoptosis via Nucleolar Stress --- p.176 / Chapter 4.7.3 --- The Origin of Nucleolar Stress Induced by Expanded CAG Transcripts --- p.178 / Chapter 5 --- Expanded CAG Transcripts Interact with Nucleolin and Deplete It from Upstream Control Element to Suppress Ribosomal RNA Transcription / Chapter 5.1 --- Nucleolin is an Interacting Partner of Expanded CAG Transcripts --- p.180 / Chapter 5.1.1 --- Nucleolin is Pulled down by S1-tagged Expanded CAG Transcripts in vitro --- p.180 / Chapter 5.1.2 --- Expanded CAG Transcripts Interact with Endogenous Nucleolin in vitro --- p.181 / Chapter 5.1.3 --- Expanded CAG Transcripts Directly Interact with Nucleolin in vitro --- p.184 / Chapter 5.2 --- RNA Recognition Motifs 2 and 3 on Nucleolin Interact with Expanded CAG Transcripts --- p.184 / Chapter 5.2.1 --- Generation of Expression Constructs Carrying Full Length Nucleolin and its Deletion Mutants --- p.184 / Chapter 5.2.2 --- Mapping of Domains on Nucleolin Required for Interacting with Expanded CAG Transcripts --- p.187 / Chapter 5.3 --- Nucleolin Regulates Ribosomal RNA Transcription by Mediating the DNA Methylation of Upstream Control Element in HEK293 Cells --- p.187 / Chapter 5.3.1 --- Nucleolin is involved in Regulating the Interaction between Upstream Binding Factor and Upstream Control Element in vitro --- p.191 / Chapter 5.3.2 --- Nucleolin is Involved in Regulating DNA Methylation Level of Upstream Control Element in vitro --- p.191 / Chapter 5.3.3 --- Nucleolin Associates with Upstream Control Element in vitro --- p.194 / Chapter 5.4 --- Expanded CAG Transcripts Deplete Nucleolin from Upstream Control Element in vitro and in vivo --- p.194 / Chapter 5.4.1 --- Expanded CAG Transcripts Compete Nucleolin with Upstream Control Element in vitro --- p.197 / Chapter 5.4.2 --- Expanded CAG Transcripts Compete Nucleolin with Upstream Control Element in vivo --- p.197 / Chapter 5.4.3 --- Expanded Polyglutamine Proteins does not Interact with Nucleolin in vitro --- p.200 / Chapter 5.5 --- Over-expression of Nucleolin Counteracts the Effect of Expanded CAG Transcripts on Ribosomal RNA Transcription in vitro --- p.200 / Chapter 5.5.1 --- Over-expression of Nucleolin Restores the Methylation Level of Upstream Control Element in Dose-dependent Manner in vitro --- p.200 / Chapter 5.5.1.1 --- The Dosage Effect of Nucleolin on DNA Hyper-methylation of Upstream Control Element Induced by Expanded CAG Transcripts in vitro --- p.202 / Chapter 5.5.1.2 --- Does-dependent Expression of Nucleolin in vitro --- p.202 / Chapter 5.5.1.3 --- The Effect of Nucleolin Over-expression on DNA Hyper-methylation of Upstream Control Element Induced by Expanded CAG Transcripts is Dose-dependent in HEK293 cells --- p.205 / Chapter 5.5.2 --- Over-expression of Nucleolin Does Not Alter the Expression Level of Expanded CAG Transcripts in vitro --- p.205 / Chapter 5.5.3 --- Over-expression of Nucleolin Relieves the Nucleolar Stress induced by Expanded CAG Transcripts in vitro --- p.208 / Chapter 5.6 --- Discussion --- p.212 / Chapter 5.6.1 --- The Physical Interaction between Expanded CAG Transcripts and Nucleolin Leads to Suppression of Ribosomal RNA Transcription --- p.212 / Chapter 5.6.2 --- Expanded CAG Transcripts Deprive Upstream Control Element of Nucleolin to Induce Toxicity --- p.212 / Chapter 5.6.3 --- Nucleolin Suppresses Expanded CAG Transcript-induced Cell Death --- p.213 / Chapter 5.6.4 --- Expanded CAG Transcripts Employ both p53-dependent and p53-independent pathways to Induce Cell Death --- p.214 / Chapter 6 --- Concluding Remarks --- p.216 / References --- p.220

When living cells are lysed in non-ionic detergents and 2M NaCl, structures are released that resemble nuclei, termed nucleoids. Nucleoids contain tenaciously attached DNA, RNA and protein. The nature of the interactions of these components is poorly understood. It is known that the DNA is attached to these structures in a looped configuration, and newly synthesised DNA is found closely associated with the attachment sites. Therefore, the speculation that these attachment sites have a functional signification other than for structural purposes has been seriously considered. To investigate these possibilities, the proteins were characterised for DNA binding activity, and the presence of any enzymatic activity. Some of the nucleoid proteins are derived from the cell surface, and specific phosphorylating and methylating activities were also detected. The significance of these findings remains to be determined. The study of the DNA-binding activity is hampered by the fact that these proteins are not readily solubilised away from the nucleic acids. However, DNA-binding proteins are present in nucleoids. No specificity for DNA sequences was demonstrable, using the protein blotting technique. In the course of these studies, a new technique was devised to enable sequence-binding proteins to be identified. Examination of the DNA close to thl attachment sites shows it to be enriched in transcriptionally active genes, and in a given population of cells, some genes are closer to the attachment sites than others. This supports the idea that genes are specifically arranged within the nucleus of any cell, and that this position is of functional significance. Direct examination of the most closely adherent DNA to these structures did not reveal any one DNA sequence that may mediate attachment.

Thesis (M.S.)--University of Michigan, 1974.

Thesis (M.S.)--University of Michigan, 1974.

Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1920. / Cover title. "Reprinted from the Transactions of the Wisconsin Academy of Sciences, Arts, and Letters, Vol. XXI." Includes bibliographical references (p. 376-377).