Hannover, University, Diss., 2003.

Thesis (Ph. D.)--Illinois State University, 1983. / Title from title page screen, viewed May 5, 2005. Dissertation Committee: Mathew J. Nadakavukaren, Derek A. McCracken (co-chairs), Jerome R. Cain, Anthony E. Liberta, David F. Weber. Includes bibliographical references (leaves 108-117) and abstract. Also available in print.

Made available in DSpace on 2014-06-11T19:31:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-09Bitstream added on 2014-06-13T18:41:23Z : No. of bitstreams: 1 cupertino_fb_dr_araiq.pdf: 10818363 bytes, checksum: 34f272c80573854af968c2e298ba0e61 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho descreve a caracterização funcional de alguns fatores de transcrição possivelmente envolvidos na regulação do metabolismo do glicogênio no fungo filamentoso Neurospora crassa. Em uma análise sistemática realizada com 69 linhagens mutantes em genes codificadores para fatores de transcrição, foram identificadas e selecionadas sete linhagens que apresentaram perfis diferentes de acúmulo de glicogênio, em relação à linhagem selvagem, tanto durante o crescimento vegetativo (30°C) como no estresse térmico (45°C). Com o objetivo de verificar o envolvimento dos fatores de transcrição selecionados na expressão dos genes gsn (glicogênio sintase) e gpn (glicogênio fosforilase), experimentos de Northern blot foram realizados e revelaram variações ao nível transcricional em algumas linhagens. A análise por Blast revelou que alguns fatores de transcrição haviam sido previamente estudados em N. crassa (CSP-1, RCO-1, NIT2) ou em outros organismos (PacC, FlbC, Fkh1) e participam na regulação de diferentes processos biológicos. O fator de transcrição PACC e a influência do pH externo sobre a regulação do metabolismo do glicogênio foram investigados mais detalhadamente neste trabalho. Os resultados mostraram que na linhagem selvagem o acúmulo de glicogênio e a expressão do gene gsn foram reprimidos em condições de pH alcalino, enquanto que o gene pacC foi superexpresso nesta condição. A linhagem mutante pacCKO mostrou perder a regulação sobre o acúmulo de glicogênio e expressão do gene gsn, tanto durante o crescimento em pH fisiológico (5,8) como alcalino (7,8). A análise de ligação DNA-proteína mostrou que a proteína PACC de N. crassa recombinante produzida em E. coli foi capaz de se ligar ao motif de DNA para a proteína PACC, presente na região promotora do gene gsn... / This work describes the functional characterization of transcription factors likely involved in glycogen metabolism regulation in the filamentous fungus Neurospora crassa. In a systematic analysis performed with 69 strains knocked-out in genes encoding transcription factors, seven strains were identified and selected by presenting profiles of glycogen accumulation different from that existent in the wild-type strain during vegetative growth (30°C) and under heat stress (45°C). In order to verify the involvement of the selected transcription factors in regulation of gsn (codes for glycogen synthase) and gpn (codes for glycogen phosphorylase) genes, Northern blot assays were performed. Differences in gene expression were observed in some strains compared to the wild-type strain. Blast analysis showed that transcription factors have been previously studied either in N. crassa (CSP-1, RCO-1, NIT2) or in other organisms (PacC, FlbC, Fkh1) participating in the regulation of different biological processes. The transcription factor PACC and the influence of the external pH under the regulation of the glycogen metabolism were further investigated. The results showed that in the wild-type strain the glycogen content and the gsn gene expression were repressed under alkaline conditions, while the pacC gene was overexpressed in this condition. The pacCKO strain showed impairments in the glycogen accumulation and gsn gene expression under normal pH (5.8) and alkaline (7.8) conditions. Protein-DNA binding analysis showed that N. crassa PACC recombinant protein produced in E. coli cells was able to bind to the pacC motif present in the gsn promoter. Binding specificity was confirmed by competition assays using an oligonucleotide containing the DNA motif and by binding to a DNA fragment containing the motif mutated by site-directed mutagenesis... (Complete abstract click electronic access below)

Thesis (Ph.D.)--York University, 2008. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 165-180). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39028

Thesis (Ph. D.)--Illinois State University, 1968. / Title from title page screen, viewed Aug. 17, 2004. Dissertation Committee: H.E. Brockman (chair), J.L. Frehn, C.W. Hardiman, A.E. Liberta, J.E. Perham, D.D. Pittman. Includes bibliographical references (leaves 61-65). Also available in print.

Thesis (Ph. D.)--University of Oregon, 2003. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 91-96). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Not available / text

The Neurospora crassa arg-2 gene encodes the small subunit of carbamoyl phosphate synthetase, the first enzyme in fungal arginine (Arg) biosynthesis. The arginine attenuator peptide (AAP), specified by an upstream open reading frame (uORF), stalls ribosomes at its termination codon in response Arg to control the translation of arg-2. In project 1, the effect of AAP and Arg on ribosome peptidyl transferase center (PTC) activity was analyzed in N. crassa and wheat germ cell-free translation extracts using the transfer of nascent AAP to puromycin as an assay. The results show that inhibition of PTC activity by the AAP and Arg is the basis for the AAP’s function. The mode of PTC inhibition appears unusual because neither a specific amino acid nor a specific nascent peptide chain length was required for AAP to function. In eukaryotic translation initiation, the stringency of start codon selection impacts initiation efficiencies at AUG codons in different contexts and at near-cognate codons (NCCs) that differ from AUG by a single nucleotide. In project 2, a codon-optimized firefly luciferase reporter was used to examine the stringency of start codon selection in N. crassa. In vivo and in vitro results indicated that the hierarchy of initiation in N. crassa is similar to that in human cells. The preferred context was more important for efficient initiation from NCCs than from AUG. In project 3, the use of NCCs was also specifically examined for the N. crassa cpc-1 gene. cpc-1 and Saccharomyces cerevisiae GCN4 are homologs specifying a transcription activator, which drives the primary transcriptional response to amino acid starvation. In vitro studies showed that uORF1 and uORF2 in cpc-1 are functionally analogous to uORF1 and uORF4 in GCN4. uORF1 promotes reinitiation at downstream start codons. uORF2 inhibits translation from the main cpc-1 start codon. Four NCCs in the CPC1 reading frame and upstream of uORF2 can also be used for translation initiation. In summary, we explored uORF-mediated translational regulation and the use of NCCs as initiation codons. Taken together, these studies establish N. crassa as a model system to examine mechanisms contributing to translational control including initiation and termination.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves [41]-44.