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 (Ph. D.)--Northeastern University, 2008. / Title from title page (viewed March 3, 2009). Graduate School of Arts and Sciences, Dept. of Physics. Includes bibliographical references (p. 133-155).

Thesis (M.S.)--Brandeis University, 2009. / Title from PDF title page (viewed on May 29, 2009). Includes bibliographical references.

Thesis (Ph.D.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Cell Biology. Title from pdf file main screen (viewed on November 1, 2009). Includes 2 video recordings. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri--Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 217-230). Also available on the Internet.

Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 90-101). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9947978.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 167-181).

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

RNA:protein interactions are central in many cellular processes, including activation of innate immune responses against microbial infection. Their study is essential to better understand the diverse biological events that occur within cells. However, isolation of RNA:protein complexes is often laborious and requires specialized techniques. This thesis is concerned with attempts to develop an improved purification protocol to isolate specific RNA:protein complexes. Taking advantage of the specific interaction of the Pseudomonas aeruginosa PP7 protein with its cognate RNA binding site, termed the PP7 recognition sequence (PRS), the aim was to identify cellular proteins involved in activating cell-signalling pathways, including the interferon-induction cascade, following viral infection with stocks of parainfluenza virus 5 (PIV5) rich in copyback defective interfering (DI) particles. Copyback DI genomes are powerful inducers of IFN and, here, I show they also activate the induction of IL-6, IL-8 and TNFα; cytokines that also have antiviral properties. Following the successful cloning of the PRS into a copyback DI genome, we investigated conditions for optimal in vitro capture of DI-PRS:protein complexes by PP7 on Dynabeads. When tested, the protocol led to the successful capture of ILF3 and PKR, two dsRNA binding proteins induced by IFN. We further developed a tap-tagging system to minimize the presence of non-specifically bound proteins to Dynabeads that may interfere with future mass spectrometry analysis. To isolate DI-PRS RNA:protein complexes from infected cells, attempts were made to rescue replicating DI-PRS genomes in the context of wild type PIV5. Similarly, efforts were made to isolate influenza A virus RNPs that contained the PRS in the neuraminidase (NA) gene from infected cells using the PP7-based protocol developed. However, for reasons discussed, unfortunately RNA:proteins complexes were not successfully purified from infected cells in either case.

Please read the abstract in the section 05summary, of this document / Dissertation (MSc (Biochemistry))--University of Pretoria, 2007. / Biochemistry / unrestricted