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In eukaryotes chromatin function and organisation is defined and mediated by the recognition of DNA and histone modifications, possibly in combinatorial patterns. Cell cycle progression, chromatin organisation and DNA replication are linked and depend on one another. However, the mechanism by which these biological processes are inter-regulated is yet far from clear. The origin recognition complex (ORC) is responsible for the initiation of DNA replication and plays an important role in cell cycle progression. Through nucleosome affinity purifications, LRWD1 (Leucine rich repeat and WD repeat domain containing 1 protein) has been identified as a novel ORC interacting protein. Since, LRWD1 has been shown to act as an adaptor that mediate ORC binding to chromatin. We have characterised the function of LRWD1 from different angles by investigating how LRWD1 might be regulated by phoshorylation, by uncovering interacting partners of LRWD1 and by studying how LRWD1 interacts with differentially modified nucleosomes. We report here evidence that phosphorylation of LRWD1 might be involved in regulating the localisation of the protein in the cell potentially by altering a nuclear localisation sequence (NLS). Indeed, stable cell lines expressing phospho-mutants of LRWD1 show different distribution of LRWD1 depending on the phosphorylation status. Furthermore, proliferation defects were observed in the LRWD1 mutant cell. Investigation of LRWD1 interacting proteins in HeLa S3 cells by immunoprecipitation and mass-spectrometry revealed the cohesin subunit SMC3 as an LRWD1-interacting protein. Interestingly, LRWD1 binding sites in the genome, identified by chromatin immunoprecipitation linked to high throughput sequencing (ChIP-seq) positively correlate with SMC3 binding sites. Further analysis revealed that LRWD1 binding sites are enriched at High-C contact points within topologically associating-domains and, interestingly, preferentially localise to the base of chromatin loops in a published 3C study of the CFTR locus. The data so far suggest that LRWD1 could potentially be involved in controlling DNA replication through chromatin architecture. To determine whether LRWD1 preferentially recruits ORC to differently modified nucleosomes, we expressed and purified recombinant LRWD1, ORC 2-5 and assembled modified nucleosomes and performed in vitro nucleosomes pulldowns. We were able to confirm that LRWD1 preferentially binds to repressive chromatin marks (heterochromatin) and that the binding is independent of ORC.

The human Interleukin-3 (IL-3) and Granulocyte-Macrophage Colony-Stimulating-Factor (GM-CSF) genes are two closely linked cytokine genes that are located within a conserved cytokine gene cluster. They are expressed in an inducible tissue-specific manner in a variety of haemopoietic cell types, and they contribute to the regulation of inflammatory responses arid haemopoiesis. For this reason their expression is strictly regulated. The experiments in this thesis describe an investigation into the factors and DNA elements involved in the control and regulation of these genes during T cell development. They focus in particular on the roles that DNase I hypersensitive sites (DHSs) and the nuclear proteins CTCF and RAD21 play within the GM-CSF/IL-3 gene locus.

In the United States the lack of mathematic knowledge of citizens has remained a significant problem. Both national and international assessments of mathematical knowledge of students have consistently reported poor results. Given the importance of mathematics education in college attendance and career options, finding ways to improve the mathematical knowledge of students in the United States is a critical concern. One group consistently underperforming in mathematics is students with emotional disturbance (ED). According to the National Math Advisory Panel (NMAP), additional research addressing the social, affective and motivational factors associated with mathematics learning and performance is needed. A qualitative multiple case study design was used to examine the experiences students with ED in two different math placements. Semi-structured interviews, participant observation and document review informed the current study. The selection of instructional strategies, the classroom environment and parental engagement emerged as common sources in the development of the students' self-efficacy beliefs, beliefs about their ability in math and the value they placed on math. Recommendations for middle school math teachers of students with ED are provided. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

The high frequency response of a circular ring of rectangular cross section interior to a conical shell excited by a blast wave is examined. The ring supports a rigidly attached mass during excitation. It is hypothesized that the response is a function of the four excitation parameters which characterize the loading. These are: peak reflected pressure; characteristic time (pulse duration); wave engulfment time; and circumferential distribution. These parameters are varied over a range of interest in an effort to ascertain the structural sensitivity to such perturbations. A series of tests sponsored by the Department of the Army and the Martin Marietta Corporation were conducted by the Stanford Research Institute on the missile. Data acquired during these tests will be used to verify and support the hypothesis. In addition analytic correlation is presented based on parametric studies performed on a simple two degree of freedom ring model excited by a local pressure forcing function. The experimental data indicated a linear dependence of the structural response on variations in pressure, duration and engulfment. The analytic results indicated higher sensitivities by comparison, but supported the experimental results in general.