No description available.

The annals of orthodontics are filled with studies aimed to understand how extraction orthodontic treatment might change the face. Although many studies have addressed profile changes due to extraction treatment, fewer studies have focused on how extractions change a patients smile. With the advent of surface imaging systems such as 3dMD, it is now possible to visualize the smile, and any changes incurred during orthodontic treatment, in three dimensions. Subjects for this study were chosen from the pool of 11-18 year old patients treated at the Podray Orthodontic Clinic at the Temple University Kornberg School of Dentistry. Subjects were Cl II patients, and must have been treated with either extraction of any combination of premolars or treated without extraction. Subjects were divided into four experimental groups based on two characteristics- mandibular angle (those with angles greater than 28o versus those with angles less than 28o) and treatment (extraction versus non-extraction). The resulting groups were separated as follows: high-angle extraction patients (n=8), low-angle extraction patients (n=6), high-angle non-extraction patients (n=7), and low-angle non-extraction patients (n=15). For each subject initial and final 3dMD images were superimposed using 3dMD Vultus software. A color histogram was constructed to visualize changes during treatment. The cheeks, commissures, upper and lower lips, chin, and nose, were also landmarked, and the changes in these landmarks were calculated. Volume changes were also calculated between pre and post treatment 3D data. Results showed that the lower lip and right commissure changes between high-angle extraction and non-extraction groups were statistically significant. A qualitative analysis of the histograms further supported these findings. In general, a greater change in soft tissue landmarks and soft tissue volumes could be seen in high-angle patients than low-angle patients. Differences in the changes that result from treatment type (extraction vs. non-extraction) were seen in the high-angle group. In contrast, similar changes result from treatment type (extraction vs. non-extraction) in the low-angle groups. Furthermore, the lip changes seen in extraction patients upon smiling are very similar to those changes seen in the same patient in repose. Most interestingly, soft tissue differences of the face due to treatment, growth, or both, seem to disappear upon smiling, with the exception of the lips. Qualitative assessment of these changes in the smile might be a more appropriate method for identifying soft tissue changes than statistical analyses. Similar studies with larger sample sizes are a promising direction for future research. / Oral Biology

The precise regulation of Major Histocompatibility class II (MHC-II) genes plays an important role in the control of the adaptive immune response. MHC-II genes are expressed constitutively in only a few cell types, but their expression can be induced by the inflammatory response cytokine interferon gamma (INF-γ). The regulation of MHC-II is controlled by a Master Regulator, the class II transactivator (CIITA). Multiple studies have shown that CIITA regulated expression of MHC-II is controlled and induced by INF-γ. It has been also shown that a functional CIITA gene is necessary for the expression of MHC-II genes. CIITA is thus a general regulator of both constitutive and inducible MHC-II expression. Although much is known about the transcription factors necessary for CIITA expression, there is little information as to the epigenetic modifications and the requisite enzymes needed to provide these transcription factors access to DNA. Previous studies in the Greer lab have shown that increased levels of acetylation of histones H3 upon INF-γ stimulation, as does tri-methylation of H3K4 upon prolonged cytokine stimulation. Similar observations were made at early time points post IFN-γ stimulation, where there is an instantaneous increase in the levels of H3K18ac and H3K4me3. In contrast to this, the levels of silencing modifications begin to drop with in the first 20 minutes of IFN-γ stimulation. The binding of STAT1 reaches its peak at about 60 minutes and the first transcripts for the protein start to appear as early as 40 minutes post the cytokines stimulation. Our study is the first to link the rapidly occurring epigenetic changes at the CIITA promoter pIV to EZH2

Orientador: Ary dos Santos-Pinto / Banca: Ana Claudia Moreira Melo / Banca: Dirceu Barnabé Raveli / Resumo: A deficiência de dados na literatura nos levou a avaliar o efeito do tratamento com o aparelho Bionator de Balters nas alterações das dimensões e relacionamento dos arcos dentários em crianças com má-oclusão Classe II, divisão 1 de Angle. O grupo experimental foi consistituido de 36 pares de modelos de pacientes leucodermas com idades entre 7 anos e 10 meses e 11 anos e 8 meses sendo 10 do gênero feminino e 8 do gênero masculino. A seleção da amostra teve como critérios de inclusão a presença dos incisivos centrais e laterais erupcionados, ausência de apinhamento dentário e relação transversal dos arcos normais. Um grupo controle (pseudo-amostra controle) foi simulado a partir de uma amostra obtida por Moyers com idade e gêneros aproximadamente iguais ao grupo experimental. A análise dos modelos constou de 24 medidas das quais 18 puderam ser comparadas com a pseudo-amostra. A aplicação do teste de Levene mostrou evidências estatísticas de semelhança entre os grupos. Procedeu-se então a análise estatística que mostrou alterações significantes (p<0,005) nas variáveis indicativas de distância intermolares superiores, sobressaliência horizontal, comprimento total do arco superior, comprimento anterior do arco superior, comprimento posterior do arco superior, relação molar direita, relação molar esquerda, relação canino direita e relação canino esquerda. Por outro lado não houve alteração significante em relação as medidas do arco inferior e distancia intercaninos do arco superior. Pode ser concluído com base nos resultados encontrados que o uso do aparelho Bionator de Balters teve efeito favorável na melhora da correção da má-oclusão de Classe II (diminuição das relações molares e caninos) e um aumento transversal do arco superior, principalmente na região posterior do arco. / Abstract: The deficiency of data in the literature took us to evaluate the Bionator of Balters appliance in the alterations of the dimensions and relationship of the dental archs in children with malocclusion Class II, Division 1 of Angle. The experimental group was constituted of 36 pairs of cast of leucodermas patients between the age of 7 years and 10 months and 11 years and 8 months, being 10 females and 8 males. The sample selection had as criterion of inclusion the presence of the central and lateral incisor erupted, absence of crowded teeth and normal transversal relationship. A control group (pseudo-sample group) was simulated beginning from a sample obtained by Moyers with approximately the same age and gender to the experimental group. The analysis of the casts consisted of 24 measures and 18 of them could be compared with the pseudo-sample. The Leveneþs test showed statistical evidences of likeness among the groups. Statistical analysis was proceeded with showed significant alterations (p<0,005) in the variable indicatives of distance of maxillary first molars, over jet, total length of upper arch, anterior length of the upper arch, right molar relationship, left molar relationship, right canine relationship and left canine relationship. On the other hand, there wasn't significant alteration related to the lower arch and maxillary intercanines distance. It be concluded with the use of the Bionator of Balters appliance that it had a favorable effect in the improvement of the correction of the malocclusion in Class II (decrease of the molars and canines relationship) and transversal increase of the upper arch, mainly in the posterior area of arch. / Mestre

No description available.

It is evident that components of the 26S proteasome function beyond protein degradation in the regulation of transcription. Studies in yeast implicate the 26S proteasome, specifically the 19S cap, in the epigenetic regulation of transcription. Saccharomyces cerevisiae 19S ATPases remodel chromatin by facilitating histone acetylation and methylation. However, it is unclear if the 19S ATPases play similar roles in mammalian cells. We previously found that the 19S ATPase Sug1 positively regulates transcription of the critical inflammatory gene MHC-II and that the MHC-II promoter fails to efficiently bind transcription factors upon Sug1 knockdown. MHC-II transcription is regulated by the critical coactivator CIITA. We now find that Sug1 is crucial for regulating histone H3 acetylation at the cytokine inducible MHC-II and CIITA promoters. Histone H3 acetylation is dramatically decreased upon Sug1 knockdown with a preferential loss occurring at lysine 18. Research in yeast indicates that the ortholog of Sug1, Rpt6, acts as a mediator between the activating modifications of histone H2B ubiquitination and H3 methylation. Therefore, we characterized the role the 19S proteasome plays in regulating additional activating modifications. As with acetylation, Sug1 is necessary for proper histone H3K4 and H3R17 methylation at cytokine inducible promoters. In the absence of Sug1, histone H3K4me3 and H3R17me2 are substantially inhibited. Our observation that the loss of Sug1 has no significant effect on H3K36me3 implies that Sug1’s regulation of histone modifications is localized to promoter regions as H3K4me3 but not H3K36me3 is clustered around gene promoters. Here we show that multiple H3K4 histone methyltransferase subunits bind constitutively to the inducible MHC-II and CIITA promoters and that over-expressing one subunit significantly enhances promoter activity. Furthermore, we identified a critical subunit of the H3K4 methyltransferase complex that binds multiple histone modifying enzymes, but fails to bind the CIITA promoter in the absence of Sug1, implicating Sug1 in recruiting multi-enzyme complexes responsible for initiating transcription. Finally, Sug1 knockdown maintains gene silencing as elevated levels of H3K27 trimethylation are observed upon Sug1 knockdown. Together these studies strongly implicate the 19S proteasome in mediating the initial reorganization events to relax the repressive chromatin structure surrounding inducible genes.

Major Histocompatibility Complex (MHC) class II molecules are indispensable arms of the im-mune system that present extracellular antigens to CD4+T cells and initiate the adaptive immune response. MHC class II expression requires recruitment of a master regulator, the class II trans-activator (CIITA). How this master transcriptional regulator is recruited, stabilized and degraded is unknown. The 26S proteasome, a master regulator of protein degradation, is a multi-subunit complex composed of a 20S core particle capped on one or both ends by 19S regulatory particles. Previous findings have linked CIITA and MHC class II transcription to the ubiquitin proteasome system (UPS) as mono-ubiquitination of CIITA increases its transactivity whereas poly-ubiquitination targets CIITA for degradation. Increasing evidence indicates individual ATPase subunits of the 19S regulator play non-proteolytic roles in transcriptional regulation and histone modification. Our initial observations indicate proteasome inhibition decreases CIITA transac-tivity and MHC class II expression without affecting CIITA expression levels. Following cyto-kine stimulation, the 19S ATPase Sug1 associates with CIITA and with the MHC class II enhan-ceosome complex. Absence of Sug1 reduces promoter recruitment of CIITA and proteasome inhibition fails to restore CIITA binding, indicating Sug1 is required for CIITA mediated MHC class II expression. Furthermore, we identify a novel N-terminal 19S ATPase binding domain (ABD) within CIITA. The ABD of CIITA lies within the Proline/Serine/Threonine (P/S/T) re-gion of CIITA and encompasses a majority of the CIITA degron sequence. Absence of the ABD increases CIITA half-life, but blocks MHC class II surface expression, indicating that CIITA requires interaction with the 19S ATPases for both its deployment and destruction. Finally, we identify three degron proximal lysine residues, lysines (K): K315, K330 and K333, and a phosphorylation site, serine (S), S280, located within the CIITA degron, that regulate CIITA ubiquitination, stability and MHC class II expression. These are the first lysine residues identified as sites of CIITA ubiquitination that are essential for MHC class II expression. These observations increase our understanding of the role of the UPS in modulating CIITA mediated MHC class II transcription and will facilitate the development of novel therapies involving manipulation of MHC class II gene expression.

Major Histocompatibility Complex Class-II (MHC-II) molecules are critical regulators of adaptive immunity that present extracellular antigens required to activate CD4+ T cells. MHC-II are regulated at the level of transcription by master regulator, the Class II Transactivator (CIITA), whose association with the MHC-II promoter is necessary to initiate transcription. Recently, much research focused on novel mechanisms of transcriptional regulation of critical genes like MHC-II and CIITA; findings that the macromolecular complex of the 26S-proteasome is involved in transcription have been perhaps the most exciting as they impart novel functions to a well studied system. Proteasome is a multi-subunit complex composed of a 20S-core particle capped by a 19S-regulatory particle. The 19S contains six ATPases which are required for transcription initiation and elongation. We demonstrate that 19S ATPase-S6a inducibly associates with CIITA promoters. Decreased expression of S6a negatively impacts recruitment of the transcription factors STAT-1 and IRF-1 to the CIITA due to significant loss in histone H3 and H4 acetylation. S6a is robustly recruited to CIITA coding regions, where S6a binding coordinates with that of RNA polymerase II. RNAi mediated S6a knockdown significantly diminishes recruitment of Pol II and P-TEF-b components to CIITA coding regions, indicating S6a plays important roles in transcriptional elongation. Our research is focused on the ways in which accessibility to and transcription of DNA is regulated. While cancers are frequently linked to dysregulated gene expression, contribution of epigenetics to cancers remains unknown. To achieve metastatic ability, tumors alter gene expression to escape host immunosurveilance. MHC-II and CIITA expression are significantly downregulated in highly metastatic MDA-MB-435 breast cancer cells. This suppression correlates with elevated levels of the silencing modification H3K27me3 at CIITA and a significant reduction in Pol II recruitment. We observe elevated binding of the histone methyltransferase to CIITApIV and demonstrate this enzyme is a master regulator of CIITA gene expression. EZH2 knockdown results in significant increases in CIITA and MHC-II transcript levels in metastatic cells. In sum, transcriptional regulation by the 19S-proteasome and histone modifying enzymes represents novel mechanisms of control of mammalian gene expression and present novel therapeutic targets for manipulating MHC expression in disease.

It is evident that components of the 26S proteasome function beyond protein degradation in the regulation of transcription. Studies in yeast implicate the 26S proteasome, specifically the 19S cap, in the epigenetic regulation of transcription. Saccharomyces cerevisiae 19S ATPases remodel chromatin by facilitating histone acetylation and methylation. However, it is unclear if the 19S ATPases play similar roles in mammalian cells. We previously found that the 19S ATPase Sug1 positively regulates transcription of the critical inflammatory gene MHC-II and that the MHC-II promoter fails to efficiently bind transcription factors upon Sug1 knockdown. MHC-II transcription is regulated by the critical coactivator CIITA. We now find that Sug1 is crucial for regulating histone H3 acetylation at the cytokine inducible MHC-II and CIITA promoters. Histone H3 acetylation is dramatically decreased upon Sug1 knockdown with a preferential loss occurring at lysine 18. Research in yeast indicates that the ortholog of Sug1, Rpt6, acts as a mediator between the activating modifications of histone H2B ubiquitination and H3 methylation. Therefore, we characterized the role the 19S proteasome plays in regulating additional activating modifications. As with acetylation, Sug1 is necessary for proper histone H3K4 and H3R17 methylation at cytokine inducible promoters. In the absence of Sug1, histone H3K4me3 and H3R17me2 are substantially inhibited. Our observation that the loss of Sug1 has no significant effect on H3K36me3 implies that Sug1’s regulation of histone modifications is localized to promoter regions as H3K4me3 but not H3K36me3 is clustered around gene promoters. Here we show that multiple H3K4 histone methyltransferase subunits bind constitutively to the inducible MHC-II and CIITA promoters and that over-expressing one subunit significantly enhances promoter activity. Furthermore, we identified a critical subunit of the H3K4 methyltransferase complex that binds multiple histone modifying enzymes, but fails to bind the CIITA promoter in the absence of Sug1, implicating Sug1 in recruiting multi-enzyme complexes responsible for initiating transcription. Finally, Sug1 knockdown maintains gene silencing as elevated levels of H3K27 trimethylation are observed upon Sug1 knockdown. Together these studies strongly implicate the 19S proteasome in mediating the initial reorganization events to relax the repressive chromatin structure surrounding inducible genes.

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