Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 128-141). Also available on the Internet.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 79-89). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 150-177). Also available on the Internet.

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.

Thesis (doctoral)--University of Stockholm, 1983. / Includes bibliographical references (p. 39-44 (first group)).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 179-239). Also available in electronic version.

Thesis (Ph. D. in Cell and Developmental Biology)--Vanderbilt University, May 2006. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 129-159).

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 150-177). Also available on the Internet.

Made available in DSpace on 2014-06-11T19:26:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-09-03Bitstream added on 2014-06-13T20:53:59Z : No. of bitstreams: 1 costa_pr_me_botib.pdf: 664900 bytes, checksum: d4b731cf5ba2463de35082d25d1fdb1e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A transcrição realizada pela RNA polimerase (RNAP) é um processo cuidadosamente controlado no desenvolvimento e na manutenção das funções vitais dos organismos. O desenvolvimento de novas técnicas e equipamentos para seu estudo, como as técnicas de pinça ótica ou magnética, a microscopia de força atômica e a fiuorescência de molécula única, complementaram os resultados dos estudos bioquímicos tradicionais e nos levaram a um maior entendimento do processo. A ocorrência de pausas em sítios específicos durante o alongamento, já observadas na década de 80, passou a ser estudada com maior interesse devido a sua importância biológica: acredita-se que essas pausas assegurem que a transcrição e a tradução ocorram simultaneamente em bactérias, permitam o dobramento correto das estruturas secundárias e terciárias do R A, facilitem a ligação de reguladores de alongamento e precedam a etapa de terminação transcricional. Modelos teóricos baseados na estabilidade termodinâmica do complexo de alongamento transcricional foram bem sucedidos na previsão da cinética do alongamento. Seus resultados indicaram que a RNAP pode ser vista como um motor molecular e sua motilidade possui características do modelo de catraca browniana. Entretanto, esses modelos consideram a presença de apenas uma polimerase realizando a transcrição. Experimentos recentes mostraram que a ocorrência de colisões entre essas enzimas durante a transcrição múltipla de um mesmo gene altera seu comportamento. Baseados nesses resultados, propomos a generalização de um dos modelos estocásticos que consideram a sequência molde para o estudo desse fenômeno. Em nossa aproximação, colisões entre as moléculas RNAP modificam a taxa de ocorrência da transcrição. A implementação do modelo foi realizada em... / The transcription of the information encoded within the DNA to the RNA molecule is exquisitely controlled during the development of the organisms and to its vital functions and has as the protagonist the RNA polymerase enzyme (RNAP). The development of single-molecule techniques, such as the magnetic and optical tweezers, atomic-force microscopy and single-molecule uorescence, increased our understanding of the process, complementing traditional biochemical studies. The non-homogeneity of the RNAP movement due to the occurrence of \pauses at speci c sites during elongation was revealed using electrophoresis gels. It is believed that these pauses ensure concurrency between transcription and translation in bacteria, allow the correct folding of RNA secondary and tertiary structures, facilitate the binding of regulating factors during elongation and preceding the transcriptional termination step. Theoretical models have been proposed to explain and predict the RNAP kinetics during the polymerization. Models based on the thermodynamic stability of the transcription elongation complex recover much of the kinetics and indicate that its movement has a Brownian ratchet mechanism. However, experiments showed that if more than one RNAP molecule initiate from the same promoter, their behavior changes and new phenomenona are observed. We proposed and implemented a theoretical model that considers collisions between RNAP molecules and predicts their cooperative behavior during multi-round transcription. The model generalizes a stochastic sequence-dependent model. In our approach, collisions between elongating enzymes modify their transcription rate values. We performed the simulations in Mathematica and compared the results of the single and the multiple-molecule transcription with experimental... (Complete abstract click electronic access below)