The sexual differentiation of the spinal nucleus of bulbocavernosus (SNB) and the bulbocavernosus (BC) and levator ani (LA) muscles that the SNB innervates, are masculinized by androgens acting on the BC/LA. The site of androgen receptors (AR) responsible for the masculinization of the neuromuscular system is not known. A potential site of action is satellite cells: proliferation of these cells is androgen-dependent and satellite cells seem to contribute to the size of the LA. Fluorescent immunohistochemistry and confocal microscopy were used to co-localize satellite cells and AR within the LA of postnatal day one and three male and female rats. Results indicate that satellite cells express AR and reveal a difference in proportion of satellite cells expressing AR between the LA and control muscle. Interpretations of these findings, including whether the relatively small proportion of AR accounted for by satellite cells is enough to masculinize the SNB system, are discussed.

H2A.Z is an essential histone variant that has multiple chromosomal functions. One such role is transcriptional regulation. However, its role in this process is complex since it has been reported to function both as a repressor and activator. Earlier work in our lab showed that H2A.Z can be post-translationally modified with monoubiquitin (H2A.Zub1) and this form of H2A.Z is linked to transcriptional silencing. We further predicted that changes in the H2A.Z ubiquitylation status directly modulated its function in transcription. Furthermore, H2A.Z-containing nucleosomes possess a unique set of post-translational modifications (PTMs), compared to H2A nucleosomes, many of which are linked to transcriptional activation. The central aim of this thesis was to characterize the role of PTMs on H2A.Z nucleosomes in transcriptional regulation. To this end, I have provided the first evidence linking H2A.Z deubiquitylation to transcriptional activation. I demonstrated that ubiquitin specific protease 10 (USP10) is a deubiquitylase that targets H2A.Z in vitro and in vivo. Moreover, I found that both H2A.Z and USP10 are required for activation of androgen-receptor (AR)-regulated genes, and that USP10 regulates the levels of H2A.Zub1 at these genes. To understand how H2A.Z engages downstream effector proteins, in the nucleosome context, we used a mass spectrometry approach to identify H2A.Z-nucleosome-interacting proteins. Many of the identified proteins contained conserved structural motifs that bind post-translationally modified histones. For example, we found that Brd2 contains tandem bromodomains that engage H2A.Z nucleosomes through acetylated H4 residues. To investigate the biological relevance of this interaction, I present evidence that Brd2 is recruited to AR-regulated genes in a manner dependent on H2A.Z and the bromodomains of Brd2. Consistent with this observation, chemical inhibition of Brd2 recruitment greatly inhibited AR-regulated gene expression. Collectively, these studies have defined how H2A.Z mediates transcriptional regulation through multiple mechanisms and pathways.

The sexual differentiation of the spinal nucleus of bulbocavernosus (SNB) and the bulbocavernosus (BC) and levator ani (LA) muscles that the SNB innervates, are masculinized by androgens acting on the BC/LA. The site of androgen receptors (AR) responsible for the masculinization of the neuromuscular system is not known. A potential site of action is satellite cells: proliferation of these cells is androgen-dependent and satellite cells seem to contribute to the size of the LA. Fluorescent immunohistochemistry and confocal microscopy were used to co-localize satellite cells and AR within the LA of postnatal day one and three male and female rats. Results indicate that satellite cells express AR and reveal a difference in proportion of satellite cells expressing AR between the LA and control muscle. Interpretations of these findings, including whether the relatively small proportion of AR accounted for by satellite cells is enough to masculinize the SNB system, are discussed.

Messenger RNA (mRNA) posttranscriptional regulation has been implicated in the development and/or progression of several diseases including many types of cancer, rheumatoid arthritis, vascular disease, and Alzheimer's disease. Differential regulation of Androgen Receptor (AR) mRNA has been associated specifically with prostate cancer progression. In this thesis, molecular beacons were developed to allow for the detection of the expression and localization of AR mRNA in live prostate cancer cells. These beacons were then applied as a tool for studying how AR mRNA regulation is involved in prostate cancer growth and advancement. Two AR mRNA targeted beacons were designed and tested in solution and in live cells to determine their functionality. The beacon-based approach for AR mRNA detection was then optimized through the use of the two beacons in tandem and alteration of their backbone chemistry. A series of validation tests were performed on these beacons, including testing their abilities to: 1) produce a feasible localization pattern, 2) discriminate between AR positive (AR+) and AR negative (AR-) prostate cancer cell lines and 3) follow stimulus-induced changes in AR mRNA expression. Based on these results, a dual chimeric beacon approach was selected to determine the role of AR mRNA regulation in two systems that represent important stages in prostate cancer growth and progression: 1) hormone stimulation of androgen-dependent prostate cancer cells and 2) progression of androgen-dependent prostate cancer cells to the androgen-independent state. Our results suggest that changes in AR mRNA expression, organization, and localization may be indicative of molecular mechanisms involved in these critical transitions associated with prostate cancer progression. Taken together, this work provides a feasibility study for visualizing changes in AR mRNA state as a diagnostic measure for evaluating the aggressiveness of the disease and demonstrates the possible utility of therapeutically targeting AR mRNA regulation in order to prevent prostate cancer advancement.

Prostate cancer is frequently diagnosed in elderly men and, despite the largely unproven survival benefits of treatment, the majority receive treatment. Treatment options include surgery, radiation, and/or androgen deprivation therapy (ADT). Risks associated with treatment include hip fracture. Current understanding suggests that hip fracture is a frequent cause of morbidity and mortality in the elderly, and both radiation treatment and ADT can increase the risk of hip fracture. It is important to understand these risks so they can be minimized and the morbidity of treatment reduced. The objectives of this study were to estimate the risk of hip fracture as a major adverse outcome of treatment for prostate cancer among elderly men. The specific objectives include estimating: 1) the risk of hip fracture and the dose-risk relationship among patients receiving curative radiation treatment, and 2) the risk of hip fracture associated with palliative ADT and relapsed ADT compared to curative ADT. The cancer diagnosis and treatment records of 32,673 men were linked to their hospital discharge abstracts. The risk of hip fracture was estimated using Cox regression and the estimates were adjusted for age, comorbidity, income, and year of diagnosis. The risk of hip fracture was 59% higher among men who received curative radiation when compared to men who received curative surgery. The risk of hip fracture fell by 6% with each one Gy increase in radiation dose between 55 and 81 Gy Biological Equivalent Dose to the hip-bone. The risk of hip fracture for subjects in the palliative ADT and relapsed ADT categories was 5.98 and 5.77 times the risk in comparison to men who received curative ADT treatment. Curative radiation treatment is associated with an increased risk of hip fracture when compared to curative surgery. The risk of hip fracture is greater with ADT for palliation and relapsed cancer than with curative treatment. Current treatments for prostate cancer contain significant risk of hip fracture for elderly men and these risks should be considered as part of the treatment decision.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 112-138).

Diss. (sammanfattning) Umeå : Univ., 2007. / Härtill 5 uppsatser.

Thesis (Ph.D.). / Written for the Dept. of Human Genetics. Title from title page of PDF (viewed 2008/02/12). Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 91-106).