No description available.

Vitamin A is known to have an important role in cellular differentiation and proliferation. In addition to regulating normal cellular processes vitamin A has also been shown to possess potent antineoplastic activity. The work in this dissertation characterizes the role of retinoic acid (RA) in cellular transformation and tumorigenesis with known oncogene involvement. These studies were initiated by examining the effects of RA on human carcinoma cell lines which express an activated c-ras gene. The bladder carcinoma, EJ/T24 (c-rasᴴ) and the two lung carcinoma cell lines, LXl (c-rasᴷ) and A2182 (c-rasᴷ), were not sensitive to RA. No inhibition of anchorage- or density-dependent growth was observed. Therefore, since these in vitro markers of transformation indicated a lack of effectiveness of RA on carcinomas containing a c-ras gene, retrovirally transformed cells were tested for RA sensitivity. Kirsten murine sarcoma, Balb/c murine sarcoma virus, and Simian sarcoma virus transformed NIH/3T3 and NRK cells were used in these studies. In contrast to the human carcinoma cell lines, anchorage-independent growth of some of the virally transformed cells was very sensitive to inhibition by RA. Anchorage-independent growth of KNRK and SSVNRK cells was sensitive to high concentrations (5 μM) of RA; whereas, Balb/cMSV3T3 and SSV3T3 were sensitive to 1-20 nM RA. BALB/cMSVNRK anchorage-independent growth was stimulated 3.5 fold by 1 μM RA. KNRK displayed a 60% reduction in anchorage-dependent growth at 10 μM RA while little inhibition was observed with the other retrovirally transformed cells. A high level of sensitivity to RA inhibition of anchorage-independent growth was correlated with the presence of cytoplasmic retinoic acid binding protein (CRABP). This indicated that CRABP may have some role in the inhibition of retrovirally induced cellular transformation. RA was shown to significantly reduce the incidence and size of Balb/cMSV3T3 cell tumors in nude mice. The inhibition of tumorigenesis in vivo therefore confirmed the results observed in vitro. To investigate the mechanism by which RA was acting to inhibit retroviral transformation, v-onc mRNA levels were examined. RA had no effect on v-onc mRNA levels in cell lines sensitive to the inhibition of transformation. The effect of RA on the relative rate of synthesis of p21, the transforming protein of KMSV and Balb/cMSV, was investigated. No effect of RA was observed in any of the cell lines. Also, GDP binding by p21 in KNRK cell was unchanged by RA treatment indicating that the functional activity of this transforming protein was not modified. RA does appear to be effective in inhibiting retrovirally induced cellular transformation and tumorigenesis. Evidence presented here indicates that this inhibition is not due to a direct effect of RA on the expression of the v-onc gene and/or gene product. Therefore, some other essential cooperating event(s) occurring within the cell are being acted upon by RA.

A cultura do maracujazeiro é de grande importância econômica para o Brasil, porém problemas fitossanitários vêm limitando a sua produção. A doença do endurecimento dos frutos causada pelo Cowpea aphid-borne mosaic virus (CABMV), é atualmente a principal doença que afeta a cultura do maracujazeiro, tendo ocorrência generalizada no Brasil, diminuindo a produtividade e a longevidade dos pomares. Devido à ineficiência dos métodos convencionais de controle desta doença, a biotecnologia mostra-se como uma ferramenta para auxiliar na obtenção de plantas resistentes ao patógeno com o uso de técnicas de transformação genética. Com o intuito de obter plantas resistentes ao CABMV, Pinto (2010) regenerou 48 plantasde P. alataem experimentos de transformação genética via Agrobacteriumtumefaciens, utilizando uma construção gênica do tipo hairpin, a qual contém um fragmento do gene da proteína capsidial do CABMV, baseando-se no conceito de resistência derivada do patógeno (PDR). Foram identificadas 22 plantas transgênicas por PCR utilizando primers específicos para amplificação do gene CP. A integração do transgene foi confirmada via Southern blot, com sonda para detecção do gene de seleção nptII. As plantas identificadas como transgênicas por PCR foram propagadas (4 plantas por linhagem), inoculadas mecanicamente com o CABMV (3x) e analisadas por teste de ELISA. As plantas infectadas foram descartadas e as remanescentes foram inoculadas por afídeos virulíferos. Após 30 dias as plantas inoculadas foram analisadas por RT-PCR e RT-qPCR para detecção do patógeno. Todas as linhagens transgênicas inoculadas indicaram a presença do vírus em pelo menos 3 dos 4 clones inoculados. Foram selecionadas 3 plantas nas quais o vírus não foi detectado após 3 inoculações mecânicas e uma via vetor, e 3 plantas que apresentaram baixa titulação viral. Estas plantas serão propagadas para plantio em campo e avaliação de resistência à infecção pelo CABMV em condições naturais de infecção / The passion fruit crop has an expressive economic importance in Brazil, however phytosanitary problems has been limiting its production. The passion fruit woodiness disease caused by Cowpea aphid-borne mosaic virus (CABMV) it\'s the currently main disease, decreasing productivity and the longevity of orchards and has a widespread occurrence in Brazil. Due to the inefficiency of the conventional methods for controlling this disease, genetic transformation techniques shown as an alternative way for obtaining pathogen resistant transgenic plants. In order to obtain transgenic plants resistant to the CABMV, Pinto (2010) regenerated 48 plants from genetic transformation experiments with P. alata using a hairpin genetic construct containing a CABMV coat protein gene fragment, based on the PDR (pathogen-derived resistance) concept, were 22 transgenic lineages were identified by PCR for the CP gene. The transgene integration was confirmed by Southern blot with a probe for the nptII gene. The transgenic plants were propagated in a total of 4 plants per lineage and then inoculated mechanically for 3 times with the CABMV. The viral replication was confirmed by ELISA. The infected plants were discarded after each inoculation and the remaining were inoculated by viruliferous aphids and analyzed by RT-PCR and RT-qPCR. All inoculated transgenic lines shown the presence of the virus in at least 3 of 4 clones. After the inoculations,3 plants showed no symptoms and 3 a very low viral titration. These plants will be propagated for field tests in natural conditions of infection by CABMV

Os estudos sobre a conversão in vitro de meristemas apicais radiculares em gemas caulinares de plantas do gênero Catasetum vêm contribuindo para uma melhor compreensão dos processos de competência, indução e determinação celular no processo de desenvolvimento, necessitando, no momento, de aprofundamento em estudos moleculares. Para tanto, a utilização de plantas transgênicas representa uma ferramenta de trabalho importante. Além disso, os métodos de transformação genética acenam como uma alternativa eficaz para o melhoramento de plantas de interesse econômico com ciclos reprodutivos longos, como as orquídeas. Desta forma, o objetivo deste projeto foi estabelecer um protocolo para transformação genética de Catasetum pileatum, utilizando tecidos meristemáticos como explantes alvos. Para tanto, avaliou-se o potencial de alguns promotores na expressão de uidA em tecidos de C. pileatum, dentre os quais destacaram-se o 35S de CaMV, o promotor do gene Pthi1 e o de PTE027, sendo que os dois primeiros foram utilizados para os experimentos de transformação genética permanente. Como explantes alvos para a transformação, foram testadas tanto gemas laterais de caules estiolados (CEs) quanto ápices radiculares (ARs), além de segmentos radiculares subapicais (SRs). Para obtenção de estruturas com maior quantidade de células em divisão celular, foi estabelecido um protocolo de cultura de tecidos a partir de segmentos radiculares subapicais (SRs). Na região proximal destes segmentos, estabeleceu-se uma estrutura globular e intumescida na presença de 0,5mg.L-1 de BA. Cortes histológicos destas intumescências revelaram a presença de grande quantidade de células em intensa divisão celular, levando, em estágios mais avançados, à formação de gemas caulinares superficiais. Estas originavam plantas após um mês em meio propício para este fim. Estes explantes foram submetidos a várias concentrações de higromicina, sendo que as concentrações escolhidas para seleção de tecidos transformados foram de 25mg.L-1 para CEs e ARs e 10mg.L-1 para SRs. CEs e ARs foram bombardeados com micropartículas de tungstênio contendo DNA plasmidial adsorvido (P35S:uidA ou Pthi1:uidA) e transferidos para meio seletivo após uma, duas ou três semanas. No entanto, estes não foram capazes de sobreviver em meio seletivo após dois meses de seleção. SRs foram bombardeados com P35S:uidA ou Pthi1:uidA. Estes foram capazes de expressar uidA entre 48h até quatro semanas, sendo que após três meses de seleção, foi observada uma gema azul transformada com Pthi1. As melhores condições para a transformação foram as seguintes: bombardeamento dos SRs recém-isolados, manutenção por duas semanas em meio não seletivo e, por fim, transferência para meio com higromicina até o término de três meses. Não obstante a necessidade de refinamentos dos procedimentos utilizados e de análises moleculares adicionais, estes resultados constituem os primeiros a indicarem a possibilidade de obtenção de plantas transgênicas de Catasetum pileatum. / Research on in vitro conversion of root apical meristems into buds in Catasetum has contributed to a better understanding of competence, induction and cellular determination processes during plant development. Nowadays It demands advances in molecular studies. To achieve this, the use of transgenic plants is an important working tool. Furthermore, genetic transformation methods seem to be an efficient alternative for improvement of commercial plants with longlife cycles, such as orchids. Therefore, the aim of these studies was to establish a protocol for genetic transformation of Catasetum pileatum, using meristematic tissues as target explants. The potential of some gene promoters to induce the expression of uidA was evaluated in C. pileatum tissues. CaMV 35S, Pthi and the PTE027 showed the best results among all tested. The CaMV 35S and the Pthi1 were used in the permanent genetic transformation experiments. Lateral buds of shoot explants (CEs), root apices (ARs) and root segments (SRs) were tested as target explants for transformation. In order to obtain material containing higher quantity of proliferating cells, a tissue culture protocol was established using root segments (SRs). The formation of a globular structure on the proximal region of the explants was observed in the presence of 0.5mg.L-1 of BA. Histological sections of these structures showed the presence of a huge quantity of cells in intense cellular division. In advanced stages, it was observed superficial bud formation on the structures. These buds have the capacity to produce whole plants within one month, in appropriated culture medium. Explants were exposed to a range of hygromycin concentrations and thereupon concentrations of 25mg.L-1 and 10mg.L-1 were chosen for selecting CEs and ARs, and for selection of SRs, respectively. CEs and ARs were bombarded with tungsten microparticules containing adsorbed plasmidial DNA (P35S:uidA or Pthi1:uidA) and it was transferred to selective medium after one, two or three weeks. Nevertheless, these explants were not capable to survive in selective medium after two months. SRs were also bombarded with P35S:uidA or Pthi1:uidA. These explants expressed uidA between 48 hours and four weeks. After three months of selection, it was possible to see a blue stained bud transformed with Pthi1. The best conditions for genetic transformation of C. pileatum were followed: bombardment of newly isolated SRs, maintenance for two weeks in non-selective medium followed of transference to hygromicin medium up to three months. Although additional experiments will still be necessary to refine transformation methods and conduct molecular analysis, the results from the present study are the first reference about genetic transformation of Catasetum pileatum plants.

by Henry, Kam Yin Cheung. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 148-160). / ZEBRAFISH (BRACHYDANIO RERIO) / ACKNOWLEDGEMENTS / LIST OF CONTENTS / ABSTRACT / ABBREVIATION / Chapter CHAPTER ONE --- INTRODUCTION / Chapter 1.1 --- Transgenic fish --- p.1 / Chapter 1.2 --- Zebrafish --- p.4 / Chapter 1.3 --- The grass carp GH gene and protein / Chapter 1.3.1 --- The genomic sequence --- p.5 / Chapter 1.3.2 --- The cDNA sequence --- p.7 / Chapter 1.3.3 --- The grass carp GH protein --- p.7 / Chapter 1.4 --- Functional aspects of promoter regions / Chapter 1.4.1 --- PEPCK --- p.9 / Chapter 1.4.2 --- RSV-LTR --- p.10 / Chapter 1.4.3 --- hMT-IIA --- p.10 / Chapter 1.4.4 --- MMTV-LTR --- p.11 / Chapter 1.5 --- Eukaryotic gene expression in cultured cells / Chapter 1.5.1 --- COS-7 and HepG2 cells --- p.11 / Chapter 1.5.2 --- Transfection system --- p.12 / Chapter 1.5.3 --- Fate of DNA after transfection --- p.13 / Chapter 1.6 --- Electroporation and microinjection as tools for gene transfer / Chapter 1.6.1 --- Electroporation: Theory and operation --- p.13 / Chapter 1.6.2 --- Microinjection: Design of microinjector --- p.16 / Chapter 1.6.3 --- Fate of DNA after gene transfer in embryos / Transient expression --- p.16 / Stable transformation --- p.17 / Inheredity of transgene --- p.17 / Chapter 1.7 --- The aims of the present study --- p.18 / Chapter CHAPTER TWO --- MATERIALS AND METHODS / Chapter 2.1 --- General techniques / Chapter 2.1.1 --- Electrophoresis of DNA / Chapter 2.1.1.1 --- Agarose gel electrophoresis --- p.19 / Chapter 2.1.1.2 --- PAGE --- p.20 / Chapter 2.1.2 --- Purification of DNA --- p.21 / Chapter 2.1.3 --- Recovery of DNA fragments / Chapter 2.1.3.1 --- Electroelution --- p.22 / Chapter 2.1.3.2 --- Geneclean kit --- p.23 / Chapter 2.1.4 --- Standard recombinant DNA techniques / Chapter 2.1.4.1 --- Dephosphorylation --- p.24 / Chapter 2.1.4.2 --- Kinasing --- p.24 / Chapter 2.1.4.3 --- Ligation --- p.24 / Chapter 2.1.4.4 --- Filling in reaction --- p.25 / Chapter 2.1.4.5 --- Transformation --- p.25 / Chapter 2.1.5 --- Minipreparation of plasmids --- p.26 / Chapter 2.1.6 --- Large preparation of plasmids / Chapter 2.1.6.1 --- Qiagene kit --- p.27 / Chapter 2.1.6.2 --- CsCl density gradient centrifugation --- p.27 / Chapter 2.1.7 --- DNA sequencing --- p.29 / Chapter 2.1.8 --- "Extraction of DNA from embryos, fry and fish" / Method 1 --- p.32 / Method 2 --- p.32 / Chapter 2.1.9 --- Probe labelling / Chapter 2.1.9.1 --- End-labelling --- p.33 / Chapter 2.1.9.2 --- Random priming --- p.33 / Chapter 2.1.10 --- CAT assay --- p.33 / Chapter 2.1.11 --- Polymerase chain reaction(PCR) --- p.35 / Chapter 2.1.12 --- Radioimmunassay(RIA) of FGH --- p.36 / Chapter 2.1.13 --- Dot blotting --- p.38 / Chapter 2.1.14 --- Southern blotting --- p.39 / Chapter 2.2 --- "Linkers, primers and probes" / Chapter 2.2.1 --- Primers --- p.41 / Chapter 2.2.2 --- Linkers --- p.45 / Chapter 2.2.3 --- Probes --- p.47 / Chapter 2.3 --- Construction of chimeric growth hormone genes / Chapter 2.3.1 --- Sources of plasmids --- p.50 / Chapter 2.3.2 --- General principles --- p.50 / Chapter 2.3.3 --- PEPCKgcGHcDNA --- p.51 / Chapter 2.3.4 --- RSVgcGHcDNA --- p.54 / Chapter 2.3.5 --- hMTgcGHcDNAcDNA --- p.56 / Chapter 2.3.6 --- MMTVgcGHcDNA --- p.58 / Chapter 2.3.7 --- "PEPCKgcGH, RSVgcGH and hMTgcGH" --- p.60 / Chapter 2.4 --- Expression of chimeric genes in cultured cells / Chapter 2.4.1 --- Culturing of COS-7 and HepG2 cells --- p.66 / Chapter 2.4.2 --- Expression of chimeric genes in COS-7 and HepG2 cells --- p.67 / Chapter 2.5 --- Zebrafish / Chapter 2.5.1 --- "Culturing, Spawning and hatching" --- p.67 / Chapter 2.6 --- Electroporation and microinjection for gene transfer / Chapter 2.6.1 --- Electroporation / Chapter 2.6.1.1 --- Tuning up electroporation --- p.69 / Chapter 2.6.1.2 --- Evidence of gene transfer by electroporation / Chapter 2.6.1.2.1 --- CAT assay --- p.71 / Chapter 2.6.1.2.2 --- Dot blot --- p.71 / Chapter 2.6.1.2.3 --- PCR and Southern blotting of PCR products --- p.72 / Chapter 2.6.1.2.4 --- Southern blotting of fish total DNA --- p.73 / Chapter 2.6.2 --- Microinjection / Chapter 2.6.2.1 --- Handling of microinjection --- p.74 / Chapter 2.6.2.2 --- Evidence of gene transfer by microinjection / Chapter 2.6.2.2.1 --- CAT assay --- p.75 / Chapter 2.6.2.2.2 --- PCR and Southern blotting of PCR products --- p.75 / Chapter 2.7 --- Phenotypic alteration of fish generated from electroporated eggs / Chapter 2.7.1 --- Electroporation and handling of fish generated from electroporation --- p.75 / Chapter 2.7.2 --- Measurement of phenotypic change in fish generated from electroporation --- p.77 / Chapter 2.8 --- Detection of transgene and expression of exogenous DNA / Chapter 2.8.1 --- Transgene detection --- p.78 / Chapter 2.8.2 --- Expression of exogenous DNA --- p.79 / Chapter CHAPTER THREE --- RESULTS / Chapter 3.1 --- Construction of Chimeric growth hormone genes / Chapter 3.1.1 --- Confirmation of integrity of chimeric genes / PEPCKgcGHcDNA --- p.80 / RSVgcGHcDNA --- p.81 / hMTgcGHcDNA --- p.81 / MMTVgcGHcDNA --- p.81 / "PEPCKgcGH, RSVgcGH and hMTgcGH" --- p.82 / Chapter 3.1.2 --- Yield of chimeric genes from CsCl density gradient centrifugation --- p.82 / Chapter 3.2 --- Chimeric gene expression in COS-7 and HepG2 cells / Chapter 3.2.1 --- Expression of chimeric genes in COS-7 cells --- p.89 / Chapter 3.2.2 --- Expression of chimeric genes in HepG2 cells --- p.93 / Chapter 3.3 --- Transfer of chimeric genes into embryos / Chapter 3.3.1 --- Electroporation / Chapter 3.3.1.1 --- Monitoring of electroporation --- p.94 / Chapter 3.3.1.2 --- Evidence for gene transfer / Chapter 3.3.1.2.1 --- CAT assay --- p.98 / Chapter 3.3.1.2.2 --- Dot blotting --- p.98 / Chapter 3.3.1.2.3 --- PCR and Southern blotting of PCR product --- p.101 / Chapter 3.3.1.2.4 --- Southern blotting of DNA from fish generated from electroporation --- p.106 / Chapter 3.3.2 --- Microinjection / Chapter 3.3.2.1 --- CAT assay --- p.109 / Chapter 3.3.2.2 --- PCR --- p.109 / Chapter 3.4 --- Phenotypic alterations of fish / The first experiment --- p.112 / The second experiment --- p.113 / The third experiment --- p.113 / The fourth experiment --- p.122 / Chapter 3.5 --- Detection of transgene and expression of exogenous DNA / Chapter 3.5.1 --- Transgene --- p.128 / Chapter 3.5.2 --- Possible expression of exogenous DNA --- p.129 / Chapter CHAPTER FOUR --- DISCUSSION / Chapter 4.1 --- Chimeric growth hormone genes --- p.132 / Chapter 4.2 --- Expression of chimeric growth hormone genes in COS-7 and HepG2 cells --- p.134 / Chapter 4.3 --- Transfer of exogenous DNA into embyros --- p.136 / Chapter 4.4 --- Phenotypic alteration of fish developed from electroporated eggs --- p.139 / Chapter 4.5 --- The possible integration and expression of exogenous DNA --- p.143 / Chapter 4.6 --- Conclusions --- p.145 / Chapter 4.7 --- Suggestions for further studies --- p.146 / REFERENCES --- p.148 / Chapter APPENDIX I --- Restriction maps / PEPCKgcGH / PEPCKgcGHcDNA / RSVgcGH / RSVgcGHcDNA / hMTgcGH / hMTgcGHcDNA / MMTVgcGHcDNA / pBH1.2 / pMSG-CAT / pUC19 / hMT-IIA / PBC12BI / RSVCAT / pUC101 / pSEl/S2 / PUCSE2/S1 / pUCS2

by Cheng Man Kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 71-76). / Abstracts in English and Chinese. / Thesis committee --- p.i / Abstract --- p.ii / Acknowledgements --- p.iv / Abbreviations --- p.v / Table of contents --- p.vii / List of figures --- p.x / List of tables --- p.xi / Chapter Chapter 1: --- General introduction --- p.1 / Chapter Chapter 2: --- Literature review --- p.3 / Chapter 2.1 --- Nutritional quality of plant proteins --- p.3 / Chapter 2.2 --- Using traditional plant breeding method to enhance amino acid quality of plant proteins --- p.3 / Chapter 2.3 --- Molecular strategies to enhance amino acid quality of plant proteins --- p.4 / Chapter 2.3.1 --- Heterologous gene expression --- p.5 / Chapter 2.3.2 --- Protein sequence modification --- p.8 / Chapter 2.3.3 --- Modification of biosynthesis pathway --- p.10 / Chapter 2.3.4 --- Synthetic gene expression --- p.11 / Chapter 2.3.5 --- Homologous gene overexpression --- p.13 / Chapter 2.4 --- Arabidopsis --- p.14 / Chapter 2.4.1 --- Arabidopsis as a model plant --- p.14 / Chapter 2.4.2 --- Transformation methods --- p.14 / Chapter 2.4.2.1 --- Direct DNA uptake --- p.15 / Chapter 2.4.2.2 --- Agrobacterium-mediated transformation --- p.15 / Chapter 2.5 --- Winged Bean Lysine-Rich protein --- p.17 / Chapter 2.5.1 --- Identification of winged bean polypeptides rich in lysine --- p.17 / Chapter 2.5.2 --- Cloning of the lysine-rich protein gene --- p.17 / Chapter 2.5.3 --- Further characterization of the WBLRP gene --- p.18 / Chapter 2.6 --- Phaseolin --- p.19 / Chapter Chapter 3: --- Expression of LRP in transgenic Arabidopsis --- p.20 / Chapter 3.1 --- Introduction --- p.20 / Chapter 3.2 --- Materials and methods --- p.21 / Chapter 3.2.1 --- Targeting LRP to cytosol --- p.21 / Chapter 3.2.1.1 --- Chemicals --- p.21 / Chapter 3.2.1.2 --- Plant materials --- p.21 / Chapter 3.2.1.3 --- Bacterial strains --- p.22 / Chapter 3.2.1.4 --- Construction of chimeric LRP gene (pBILRP-1) --- p.22 / Chapter 3.2.1.4.1 --- PCR amplification of LRP --- p.22 / Chapter 3.2.1.4.2 --- Cloning of PCR-amplified LRP into vector pD3-8 --- p.26 / Chapter 3.2.1.4.3 --- Cloning of recombinant plasmid pLRP-1 into binary vector --- p.26 / Chapter 3.2.1.5 --- Transformation of Agrobacterium with pBILRP-1 --- p.27 / Chapter 3.2.1.6 --- Vacuum infiltration transformation of Arabidopsis --- p.28 / Chapter 3.2.1.7 --- Selection of transgenic plants --- p.29 / Chapter 3.2.1.8 --- GUS assay --- p.30 / Chapter 3.2.1.9 --- DNA isolation --- p.31 / Chapter 3.2.1.10 --- PCR amplification and detection of transgenes --- p.31 / Chapter 3.2.1.11 --- Southern blot hybridization --- p.31 / Chapter 3.2.1.12 --- RNA isolation --- p.32 / Chapter 3.2.1.13 --- Reverse transcription-polymerase chain reaction (RT-PCR) --- p.32 / Chapter 3.2.1.14 --- Protein extraction and SDS-PAGE --- p.33 / Chapter 3.2.1.15 --- Protein sequencing --- p.33 / Chapter 3.2.1.16 --- Amino acid analysis --- p.34 / Chapter 3.2.2 --- Targeting LRP to protein bodies --- p.35 / Chapter 3.2.2.1 --- Chemicals --- p.35 / Chapter 3.2.2.2 --- Plant materials --- p.35 / Chapter 3.2.2.3 --- Bacterial strains --- p.35 / Chapter 3.2.2.4 --- Construction of chimeric LRP gene (pBILRP-2) --- p.35 / Chapter 3.2.2.4.1 --- Site-directed mutagenesis --- p.36 / Chapter 3.2.2.4.2 --- Cloning of the mutated phaseolin fragment into pBluescript --- p.36 / Chapter 3.2.2.4.3 --- PCR amplification of LRP --- p.39 / Chapter 3.2.2.4.4 --- Insertion of LRP into plasmid pBK/phas* --- p.39 / Chapter 3.2.2.4.5 --- Insertion of plasmid pLRP-2 into Agrobacterium binary vector --- p.41 / Chapter 3.2.2.5 --- Transformation of Agrobacterium with pBILRP-2 --- p.41 / Chapter 3.2.2.6 --- Vacuum infiltration transformation of Arabidopsis --- p.41 / Chapter 3.2.2.7 --- Selection of transgenic plants --- p.41 / Chapter 3.3 --- Results and discussion --- p.42 / Chapter 3.3.1 --- Targeting LRP to protein bodies --- p.42 / Chapter 3.3.1.1 --- Morphology of transgenic Arabidopsis --- p.42 / Chapter 3.3.1.2 --- Selection of transgenic plants --- p.42 / Chapter 3.3.2 --- Targeting LRP to cytosol --- p.46 / Chapter 3.3.2.1 --- Morphology of transgenic Arabidopsis --- p.46 / Chapter 3.3.2.2 --- Selection of transgenic plants --- p.46 / Chapter 3.3.2.3 --- Detection of GUS activity --- p.49 / Chapter 3.3.2.4 --- Integration of LRP transgene into Arabidopsis genome --- p.54 / Chapter 3.3.2.5 --- LRP transcript in transgenic Arabidopsis --- p.58 / Chapter 3.3.2.6 --- Stable accumulation of LRP in transgenic Arabidopsis --- p.61 / Chapter 3.3.2.7 --- Amino acid analysis of seed protein --- p.64 / Chapter Chapter 4: --- General discussion --- p.67 / Conclusion --- p.70 / References --- p.71

Due to recent advances in molecular biology and genomic research, numerous diseases have been given their genetic identities for which gene therapy may be a possible prescription. Gradually, the development of viral and non-viral vectors to translocate genes has become a bottleneck. For non-viral vectors, polyethylenimine (PEI) is considered as a potential vector candidate for gene delivery because of its ability to compact DNA and its intrinsic pH buffering capacity. PEI and its derivates have been widely tested in both in-vitro and in-vivo gene transfection experiments. The progress is limited due to the lack of a better understanding of the intracellular mechanism. So far, their cytotoxicity is relatively high and gene transfection efficiency is low. This study was designed to modify PEI and optimize its cytotoxicity and gene transfection efficiency. / During the complexes formation, both LLS and zeta-potential were used to follow the process. The results showed that most of anionic DNA are complexed by cationic PEI-based polymers when the molar ratio of nitrogen from PEI to phosphate from DNA (N:P) reaches ∼3, but the gene transfection reaches the highest efficiency when N:P ∼10. When N:P > 3, there exist two population of PEI chains in the solution mixture: bound to DNA and free in the solution. The bound PEI chains condense and protect DNA. Our current study confirms that it is those free PEI chains that play a vital role in promoting the gene transfection. Our preliminary data shows that the promotion mainly occurs in the intracellular space. The detailed mechanism is still lacking at this moment. Nevertheless, our finding leads to a totally different way in the development of non-viral vectors. / Further, we grafted PEI with polyethylene glycol (PEG), respectively via a reductive disulfide -S-S- and a non-degradable -C-C- bond to form two copolymer vectors. A comparative study shows that the polyplexes formed between the two copolymers and DNA are more stable than that formed between unmodified PEI and DNA under the physiological condition, presumably because the grated PEG chains form a protective hydrophilic shell on the PEI/DNA polyplexes. However, PEGylation reduces the internalization of the copolymer/DNA polyplexes in in-vitro experiments. For the two copolymer vectors, PEG-SS-PEI is 2-8 times more effective than its counterpart (PEG-CC-PEI) in the gene transfection, presumably due to the cleavage of the grafted PEG chains inside the reductive cytosol, which promotes the release and translocation of DNA. Our results demonstrate that using the disulfide as a linker is a promising approach to overcome the PEGylation dilemma in the development of low cytotoxic and high efficient non-viral polymeric vectors. / It has been known that short PEI chains are less toxic, but long chains are more effective in gene transfection. Therefore, we decide to use the disulfide bond (-S-S-) to extend short PEI chains to increase efficiency and also utilize the reductive cytosol environment to cleave such extended PEI chains to reduce their cytotoxicity inside the cell. Laser light scattering (LLS) was used to in-situ monitor the linking reaction between short PEI chains (M w = 2000 g/mol) and dithiobis(succinimidyl propionate) (DSP). The molar mass and crosslinking degree of the extended PEI chains was controlled by either the amounts or the adding rate of DSP. A comparative study of two linked PEI samples (PEI-7K-L and PEI-400K-L, respectively with M w = 6.5 x 103 and 3.8 x 10 5 g/mol) reveals that cytotoxicity and gene transfection efficiency of such extended PEI chains are related to the chain length and structure. Namely, PEI-7K-L with an extended chain structure is less cytotoxic and 2--10 times more effective in the gene transfection than the "golden standard" (PEI25K) and the widely used commercial vector, Lipofectamine 2000RTM. Comparatively, PEI-400K-L with a spherical microgel structure is ineffective in spite of its non-toxicity. Our study clearly demonstrates that a proper control of the chain length and structure is important. / by Deng, Rui. / Adviser: Chi Wu. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Yue, Yanan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 62-63). / Abstract also in Chinese. / ABSTRACT (Chinese) --- p.i / ABSTRACT --- p.iii / CONTENT --- p.v / ACKNOWLEDGMENT --- p.vii / ABBREVIATIONS --- p.viii / Chapter CHAPTER 1 --- Introduction and Background / Chapter 1.1 --- Methods of Gene Delivery --- p.1 / Chapter 1.1.1 --- Viral Delivery Systems --- p.2 / Chapter 1.1.2 --- Non-Viral Delivery Systems --- p.3 / Chapter 1.2 --- The Gene-delivery Problems --- p.7 / Chapter 1.2.1 --- Extracellular Barriers --- p.8 / Chapter 1.2.2 --- Intracellular Barriers --- p.10 / Chapter 1.3 --- Polymer-Mediated Systems for Gene Delivery --- p.13 / Chapter 1.3.1 --- Polyethylenimine (PEI)-Based Vectors --- p.13 / Chapter 1.3.2 --- Cyclodextrin-Based Vectors --- p.15 / Chapter 1.4 --- Objective and Main Achievements --- p.16 / Chapter 1.5 --- References --- p.18 / Chapter CHAPTER 2 --- Effect of Free Polyethylenimine-Mediated Polycations on Gene Delivery: Fundamentals and Vital Factors / Chapter 2.1 --- Introduction --- p.24 / Chapter 2.2 --- Experimental Section --- p.25 / Chapter 2.3 --- Results and Discussions --- p.29 / Chapter 2.3.1 --- Fundamentals --- p.29 / Chapter 2.3.2 --- Vital Factors for the Efficacy of Free Chains --- p.37 / Chapter 2.4 --- Conclusions --- p.42 / Chapter 2.5 --- References --- p.42 / Chapter CHAPTER 3 --- Effect of Free Polyethylenimine-Mediated Polycations on Gene Delivery: Mechanistic Study / Chapter 3.1 --- Introduction --- p.44 / Chapter 3.2 --- Experimental Sections --- p.46 / Chapter 3.3 --- Results and Discussion / Chapter 3.3.1 --- Potential Effect of Free PEI Chains on Cellular Uptake --- p.49 / Chapter 3.3.2 --- Potential Effect of Free PEI Chains on Endolysosomal Release --- p.51 / Chapter 3.3.3 --- Exploration on Proton Sponge Hypothesis --- p.53 / Chapter 3.3.4 --- Interactions of PEI-based Polycations and Phospholipid Membranes --- p.55 / Chapter 3.4 --- Conclusions --- p.61 / Chapter 3.5 --- References --- p.62

Bibliography: p. 189-229.

"16th September 2002." Accompanying CD contains 2 MPEG clips with accompanying text, and a copy in PDF format of: Recovery of airway cystic fibrosis transmembrane conductance regulator function in mice with cystic fibrosis after single-dose lentivirus-mediated gene transfer / M. Limberis ... [et al.], published in Human gene therapy vol. 13 (2002). Bibliography: leaves xxix-li. This thesis focuses on modulating the physical barriers of the airway epithelium with mild detergents, so as to enhance gene transfer by a HIV-1 based lentivirus vector in vivo. The efficiency of the gene transfer was evaluated in the nasal airway of C57B1/6 mice using the Lac Z marker gene. This demonstration of lentivirus-mediated in vivo recovery of CFTR function in CF airway epithelium illustrated the potential of combining a pre-conditioning of the airway surface with a simple and brief HIV-1 based gene transfer vector exposure to produce therapeutic gene expression in the intact airway.