Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 147-158).

Dissertation (Ph.D.)--University of South Florida, 2008. / Includes vita. Includes bibliographical references.

This thesis focused on the spatiotemporal patterning of classical excitatory and inhibitory synaptic contacts accounting for the majority of cerebral cortical connections, in relation to ageing and cognitive status. These investigations tested the hypothesis that higher CNS functions depend on the balance between excitatory and inhibitory synaptic connections. Glutamatergic and GABAergic presynaptic bouton densities were determined in aged animals segregated according to their cognitive status into aged and cognitively unimpaired (AU) and aged and cognitively impaired (AI), using the Morris water maze. These two groups were compared in terms of behaviour and the pattern of excitatory and inhibitory synapses. It was evident that an excitatory and inhibitory presynaptic decline is associated with age-related cognitive impairments; whereby both glutamatergic and GABAergic boutons gradually diminish from young to AU to AI. Nevertheless, the balance between excitatory and inhibitory presynaptic inputs was maintained. To determine whether postsynaptic sites differed with respect to ageing and cognitive impairments, excitatory and inhibitory postsynaptic scaffold proteins were investigated in the same cohort of segregated aged animals. There was an imbalance in density ratio between immunoreactive sites of excitatory versus inhibitory postsynaptic scaffold proteins in AI animals. This resulted from a marked decrease in the density of excitatory postsynaptic sites. To further investigate ultrastructural aspects of excitatory synapses I carried out electron microscopical studies of cerebral cortex to measure the abundance of NR2 receptor subunits of the NMDA receptor- a receptor site directly associated with excitatory postsynaptic scaffold proteins. This study revealed that NR2 immunoreactive sites were largely preserved during age-related cognitive decline with an uneven profile distribution. Finally, protein expression of specific receptor subunits and key proteins representative of excitatory and inhibitory postsynaptic sites was investigated by semi-quantitative Western blot analyses in selected cortical areas. It was clear that many of these postsynaptic proteins are affected by age and cognitive status. The most striking change was a marked up-regulation in neuroligin-1 in AI animals, which may affect the delicate balance between excitatory versus inhibitory synaptic inputs. Another notable finding was the down-regulated expression of GluR2 receptor subunits in AI animals, which should have implications for neuronal Ca2+ regulation. In conclusion, we have demonstrated the greater vulnerability of excitatory postsynaptic sites in aged and cognitively impaired animals.

Uveal Melanoma (UM) is the most common malignant intra-ocular tumor in adults. Forty-five percent of UM patients develop metastasis within fifteen years of the initial diagnosis. Cutaneous Melanoma (CM) is a highly metastatic cancer that accounts for the majority of skin cancer deaths. Current treatments are not especially effective for the metastatic phase of the disease. Therefore, the identification of new molecular targets that can be exploited in the clinic are needed. / KISS1 is a putative human metastasis suppressor gene. The purpose of this study was to investigate the expression of KISS1 in melanoma and its potential value as a prognostic marker. / From results in vitro and in vivo we were able to characterize KISS1 in UM for the first time as well as its expression at the protein level, in CM. The correlation between KISS1 expression and UM survival rate suggests an important role for KISS1 as a prognostic marker in this tumor.

To acquire its characteristic structural and functional complexity, the mammalian nervous system must undergo several critical developmental processes. One such process requires factors that regulate the decision of dividing progenitors to leave the cell cycle and activate the neuronal differentiation program. It is shown in this thesis that the murine runt-related gene Runx1 is expressed in proliferating cells on the basal side of the murine olfactory epithelium. Disruption of Runx1 function in vivo does not result in a change in the quantity of progenitors but leads to a decrease in precursor number and an increase in differentiated ORNs. These effects result in premature and ectopic ORN differentiation. Further, exogenous Runx1 expression in cultured olfactory neural progenitors causes an expansion of the mitotic cell population. In agreement with these findings, exogenous Runx1 expression also promotes cortical neural progenitor cell proliferation without inhibiting neuronal differentiation. These effects appear to involve transcriptional repression mechanisms. Consistent with this possibility, Runx1 represses transcription driven by the promoter of the cell cycle inhibitor p21Cip1 in cortical progenitors. Taken together, these findings suggest a previously unrecognized role for Runx1 in coordinating the proliferation and neuronal differentiation of selected populations of neural progenitors/precursors. / Another significant step in the development of the mammalian nervous system is the acquisition of distinctive neuronal traits. This thesis also shows that Runx1 is expressed in selected populations of postmitotic neurons of the murine embryonic central and peripheral nervous systems. In embryos lacking Runx1 activity, hindbrain branchiovisceral motor neuron precursors of the cholinergie lineage are correctly specified but then fail to enter successive stages of differentiation and undergo increased cell death resulting in neuronal loss in the mantle layer. Runx1 inactivation also leads to a loss of selected sensory neurons in trigeminal and vestibulocochlear ganglia. These findings uncover previously unrecognized roles for Runx1 in the regulation of neuronal subtype specification. / This thesis thus presents a novel factor which functions at several steps in the development of the mammalian nervous system and adds to the growing body of work on the processes involved in elaborating such a complex and vital structure.

Saccharomyces cerevisiae has developed mechanisms in order to survive harsh environmental conditions. This species responds to stresses such as ethanol, heat, and weak acid exposure via two well-characterized stress response pathways. These typically involve either the Hsf1p or the Msn2/4p transcriptional regulators. Recently, our lab has begun to characterize a member of the zinc cluster protein family: Asg1p (Activator of Stress Genes, systematic name: YIL130W), which is presumed to stimulate stress response genes independently of the Hsflp and Msn2/4p pathways. Previous work has revealed five target genes of Asg1p (HSP30, STP4, YER130C, TPO2, YRO2) thought to be involved in this novel stress response pathway. In this study, we attempted to better characterize the role of Asg1p and its target genes during stress induction. We first determined if the induction of certain Asg1p target genes by stress is strain specific. HSP30 induction by heat shock is specific to the W303 strain as shown by primer extension analysis. We then generated the deletion strains Deltaasg1 and Astp4 in W303. We observed a loss of induction of HSP30 in the Deltaasg1 deletion strain when cells were exposed to ethanol. This led us to believe that Asg1p does play a role in the stress response pathway. Also, we attempted to globally define the target sites of Asg1p in vivo on a genome-wide scale by combining Chromatin Immuno Precipitation with microarrays (ChIP-chip). We identified eight putative Asg1p target genes: YRO2, HSP78, ZRT2, ZRT1, MSN4, STP4, TPO2, and HSP30.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Feb. 6, 2008). Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 1989. / Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.