Transcription, the first step in gene expression, is a highly regulated process which relies on a multi-protein complex to occur. Among these proteins are transcription factors, including initiation and elongation factors, which play differing roles in early and late stages of transcription. The mechanisms of transition from transcription initiation to elongation are not well understood in archaea, nor are the structures of the transcription factors involved. For transcription to occur in vitro, transcription factors TATA binding protein (TBP) and Transcription Factor B (TFB) are sufficient to allow RNA polymerase (RNAP) to synthesize RNA from template DNA. Another factor, Transcription Factor E (TFE), can also join the initiation complex and is likely to be essential in vivo. TFE is known to contribute to initiation by enhancing promoter opening, and while it has been shown to persist in elongation complexes, its role after initiation is unknown. Spt4/5, the archaeal homolog of the only universally conserved RNAP-associated factor, is known to join complexes in elongation steps and enhance processivity of the polymerase. However, if Spt4/5 joins pre-initiated complexes, it has been shown to inhibit transcription activity. The experiments in this thesis show that TFE and Spt4/5 participate in a crucial interchange at the upstream fork of the transcription bubble that helps define the timing of Spt4/5 binding. Using unnatural amino acid crosslinking techniques, the points of proximity between specific regions of these two factors and the template DNA have been mapped to identify possible sites of interaction. Competitive crosslinking assays indicate the exact timing of the shift in affinity between TFE and Spt4/5 for their shared binding site on RNAP. These data, combined with transcription assays, suggest a new role for TFE in preventing premature Spt4/5 binding, corresponding with a unique localized mobility within the winged helix of TFE.

Thesis (Ph. D.)--Ohio State University, 2006. / Full text release at OhioLINK's ETD Center delayed at author's request

 As a neuropeptide, both secretin and secretin receptor are expressed in the central nervous system (CNS). It has been revealed that the activities of secretin on hypothalamic cells of rodents are important for osmoregulation and food intake. In the present study, embryonic mouse hypothalamic cell line N42 was used to study the promoter activity of mouse secretin receptor (mSR). By 5′ deletion analysis, a promoter element was identified within ?282 to ?443, relative to the ATG codon, and it contains a GC-box (-297 to -286), a ras responsive element (RRE) (-289 to -276) and an E-box (-416 to -411). Electrophoretic mobility shift assay (EMSA) and supershift analyses showed that Sp1 interacted with the GC-box, another zinc finger As a neuropeptide, both secretin and secretin receptor are expressed in the central nervous system (CNS). It has been revealed that the activities of secretin on hypothalamic cells of rodents are important for osmoregulation and food intake. In the present study, embryonic mouse hypothalamic cell line N42 was used to study the promoter activity of mouse secretin receptor (mSR). By 5′ deletion analysis, a promoter element was identified within ?282 to ?443, relative to the ATG codon, and it contains a GC-box (-297 to -286), a ras responsive element (RRE) (-289 to -276) and an E-box (-416 to -411). Electrophoretic mobility shift assay (EMSA) and supershift analyses showed that Sp1 interacted with the GC-box, another zinc finger / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

Not available / text

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available in print.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 108-123). Also available in electronic version.

Thesis (Ph. D.)--Case Western Reserve University, 2008. / [School of Medicine] Department of Molecular Biology and Microbiology. Includes bibliographical references.

Thèses (Ph.D.)--Université de Sherbrooke (Canada), 1999. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Thèses (M.Sc.)--Université de Sherbrooke (Canada), 2002. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.