Huntington’s disease (HD) is caused by expression of the huntingtin gene containing an expanded CAG repeat. N-terminal mutant huntingtin protein (N-mHtt) accumulates in the nucleus and impairs transcription of a subset of genes through incorporation into transcriptional complexes or sequestration of proteins away from the promoter. CREB-binding protein (CBP) is a transcriptional co-activator and acetyltransferase (AT) that binds to N-mHtt. We hypothesized that overexpressing CBP fragments that lack a promoter association domain would block N-mHtt-mediated transcriptional dysregulation and toxicity. We found that overexpressing full-length CBP or CBP fragments did not reverse transcriptional dysregulation, but did decrease toxicity in a cell model of HD. Overexpressing fragments of CBP containing the AT domain increased toxicity in wild-type cells, while overexpressing a fragment lacking this domain had no effect. We conclude that excess AT activity was detrimental in wild-type cells, while overexpressing CBP or CBP fragments was protective in HD cells.

INTRODUÇÃO: A Síndrome de Rubinstein-Taybi (RTS) é uma doença genética rara, caracterizada por dismorfismos craniofaciais típicos, polegares e háluces alargados, deficiência mental e baixa estatura. A incidência estimada é de 1: 125 000 a 1: 330000 nativivos. A SRT geralmente ocorre esporadicamente, mas pode ser herdada com um padrão de herança autossômico dominante. O diagnóstico da SRT é essencialmente clínico. OBJETIVOS: Realizar o estudo genético-clínico e citogenético em 30 pacientes brasileiros com SRT, e descrever de forma sistematizada a freqüência de dismorfismos faciais e malformações múltiplas encontradas. MÉTODOS: Neste estudo observacional retrospectivo e prospectivo, os pacientes foram seguidos no período de agosto de 2005 a junho de 2009. O cariótipo com bandeamento G foi realizado em todos os pacientes. RESULTADOS: A maioria dos pacientes avaliados foi do sexo feminino (60%). As seguintes características foram observadas em todos os pacientes da nossa casuística: atraso de desenvolvimento neuropsicomotor, ponta nasal voltada para baixo, columela proeminente, sorriso característico, dificuldades alimentares na infância, persistência dos coxins fetais, falanges distais dos polegares alargadas e pés planos. A baixa estatura e a microcefalia foi observada em 80% e 76% dos casos, respectivamente. As principais características craniofaciais observadas foram: fronte proeminente (86%), ponte nasal larga (60%), hipertelorismo (70%), sobrancelhas espessas e arqueadas (96%) cílios longos em 93%, prega epicântica (76%), fissura palpebral infra vertidas (76%), abertura bucal estreita (93%), retrognatismo (76 %), sorriso característico em 100%, palato alto e estreito (93%), anomalias dentárias (83%). Outras anomalias identificadas foram: estrabismo, erros de refração, obstrução do canal lacrimal, háluces e polegares alargados, angulação de polegares, anomalias do pavilhão auricular (rotação/posição/tamanho/forma), angulação do hálux, clinodactilia, sobreposição dos pododáctilos, falanges distais alargadas de outros dedos, marcha rígida, hipotonia, sopro cardíaco, cardiopatia congênita, criptoquidia, hemangioma plano e hipertricose. Uma paciente apresentou translocação recíproca de novo 46, XX, t (2; 16)(q36.3; p13.3). CONCLUSÕES: A raridade da SRT e o amplo espectro das manifestações clínicas pode atrasar o diagnóstico clínico. A média da idade ao diagnóstico dos nossos pacientes com SRT foi de três anos e oito meses. Todas as crianças devem receber avaliação por geneticista pediátrico, cardiologista, oftalmologista, neuropediatra, e odontopediatra / INTRODUCTION: Rubinstein-Taybi syndrome (RTS) is a rare genetic disorder characterized by distinctive craniofacial dysmorphisms, broad thumbs and toes and mental and statural deficiency. The prevalence of RTS has been estimated to be 1 in 125000 to 1: 330000 live births. RTS usually occurs sporadically although it can be inherited as an autosomal dominant disorder. The diagnosis of RTS is primarily based on clinical features. OBJECTIVES: We performed a clinical and cytogenetic assay in a group of 30 Brazilian RTS patients. We also decribed the frequencies of facial dysmorphisms and multiple malformations. METHODS: In this observational retrospective and prospective study, the patients were followed from August 2005 to June 2009. Chromosomal analysis was performed by G-banding karyotype. RESULTS: Most of the patients were female (60%).The following abnormalities were present in all of the patients: delayed psychomotor development, beaked nose, proeminent collumel, typical facies, broad thumbs and toes, flat feet, joint laxity, feeding problems during the childhood, and finger pads. Short stature was present in 80%, and microcephalia in 76% of the cases, respectively. Main craniofacial characteristics are frontal bossing (86%), wide nasal bridge (60%), ocular hyperthelorism (70%), high arched eyebrows (96%), long eyelashes (93%), epicathal folds (76%), downslanting palpebral fissures (76%), small opening of the mouth (93%), retrognathism (76%), grimacing smile (100%), high arched palate (93%), and dental anomalies (83%). Other findings were: strabism, refractive error, lacrimal obstruction, wide thumb and halux, angulated thumbs, external ears anomalies (rotation, implantation and morfology), angulated halux, clinodactyly, crowded toes, broad distal falanges of other fingers, stiff gait, hipotonia, cardiac murmur, congenital heart defect, undescendent testis, hypertrichosis, and hemangioma. One female patient has found to have a reciprocal de novo translocation t(2;16)(q36.3;p13.3) on G-banding karyotype CONCLUSIONS: The rarity of RTS and the wide spectrum of clinical manifestations, may delay the clinical diagnosis of RTS. The average age at the diagnosis of our patients was 3 years and 8 months. All children of RTS should receive an evaluation by a pediatric geneticist, cardiologist, ophthalmologist, pediatric neurologist, and pediatric dentist

A Síndrome de Rubinstein-Taybi (RTSs) é uma doença rara de herança autossômica dominante, caracterizada por dismorfismos craniofaciais, polegares e háluces alargados, deficiência intelectual e de crescimento. RTSs tem sido associada com mutações no gene CREBBP (CBP) e mutações menos frequentes no gene EP300 que foram descritas em oito indivíduos. CBP e p300 possuem alta homologia e são extremamente importantes em várias vias de sinalização, principalmente como coativadores de transcrição e na acetilação das histonas. Nosso estudo baseou-se na análise de alterações moleculares por sequenciamento direto do CBP, FISH e array-CGH em 20 pacientes com RTSs. Dos 20 pacientes avaliados por sequenciamento direto foram identificadas oito alterações moleculares, dentre estas, seis são alterações moleculares novas as quais não foram descritas na literatura, são elas: i) duas deleções (p.M747fs STOP830 e p.G1011fs STOP1021) ii) duas alterações do tipo nonsense (p.Arg1341X, p.Arg1498X) iii) três do tipo missense (p.Arg1907Trp, p.Leu604Pro e p.His1291Arg). Também identificamos um polimorfismo de único nucleotídeo (SNP) (rs115594471/ c.5874CT). Dois pacientes apresentaram deleção do gene CBP em um dos alelos, identificado pelo método array-CGH. Outro, apresentou uma translocação aparentemente equilibrada t(2;16), cuja análise subsequente com FISH revelou uma quebra na região do CBP. Neste trabalho, a taxa de detecção de alteração molecular no CBP por sequenciamento direto foi de 40% (08/20). Porém, a taxa de detecção das alterações moleculares no CBP foi de 55% (11/20), considerando a combinação das diferentes técnicas utilizadas (FISH, sequenciamento direto e array-CGH). Não houve correlação genótipo-fenótipo, exceto por uma maior frequência da presença de epicanto nos pacientes com alteração no CBP. Os resultados obtidos neste trabalho servem como o diagnóstico molecular para os pacientes com RTSs atendidos no Ambulatório do Laboratório de investigação Médica 001 (ALIM 001) do Instituto da Criança - FMUSP, contribuindo para uma melhor orientação médica, como também para realização do aconselhamento genético às famílias / Rubinstein-Taybi syndrome (RTSs) is a rare autosomal dominant disease characterized by craniofacial dysmorphisms, broad thumbs and toes, mental and growth deficiency. RTS has been associated with CREBBP (CBP) gene mutations and less frequently with mutations in EP300 gene, which have been reported in eight individuals. CBP and p300 have high homology and are extremely important in many signaling pathways especially as transcriptional coactivators and histone acetylation. Our study was based on the alteration analysis by direct sequencing of the CBP, by FISH and array-CGH in 20 RTSs patients. We identified eight molecular alterations in 20 RTSs patients evaluated by direct sequencing: i) two deletions (p.M747fs STOP830 and p.G1011fs STOP1021) ii) two nonsense alterations (p.Arg1341X and p.Arg1498X) iii) Three missense alteration (p.Arg1907Trp, p.Leu604Pro and p.His1291Arg). Single-nucleotide polymorphism were also identified (rs115594471 / c.5874CT), and six of these are new molecular alterations, not described in literature. Two RTSs patients studied had CBP gene deletion in one allele, identified by array-CGH method. Other patient, presented with apparent balanced translocation t(2;16) in which the subsequent analysis using FISH, showed a break in region of CBP. In this work, the rate of detection of molecular alteration in CBP by direct sequencing in RTSs patient was 40.0% (08/20). However, the rate of detection of molecular alteration in CBP was 55.0% (11/20), considering the combination of different techniques (FISH, direct sequencing and array-CGH. No significant correlation could be established in this study between the different types of mutations and genotype-phenotype of RTSs patients, except a higher frequency of the presence of epicanthus in the RTS patients with alteration in the CBP. The results of this study serve as a molecular diagnosis for RTSs patients treated at the Ambulatory of the Medical Investigation Laboratory 001 (ALIM 001) of the Instituto da Criança - FMUSP, and this contributes to better clinical management, such as making an appropriate genetic counseling for families

INTRODUÇÃO: A Síndrome de Rubinstein-Taybi (RTS) é uma doença genética rara, caracterizada por dismorfismos craniofaciais típicos, polegares e háluces alargados, deficiência mental e baixa estatura. A incidência estimada é de 1: 125 000 a 1: 330000 nativivos. A SRT geralmente ocorre esporadicamente, mas pode ser herdada com um padrão de herança autossômico dominante. O diagnóstico da SRT é essencialmente clínico. OBJETIVOS: Realizar o estudo genético-clínico e citogenético em 30 pacientes brasileiros com SRT, e descrever de forma sistematizada a freqüência de dismorfismos faciais e malformações múltiplas encontradas. MÉTODOS: Neste estudo observacional retrospectivo e prospectivo, os pacientes foram seguidos no período de agosto de 2005 a junho de 2009. O cariótipo com bandeamento G foi realizado em todos os pacientes. RESULTADOS: A maioria dos pacientes avaliados foi do sexo feminino (60%). As seguintes características foram observadas em todos os pacientes da nossa casuística: atraso de desenvolvimento neuropsicomotor, ponta nasal voltada para baixo, columela proeminente, sorriso característico, dificuldades alimentares na infância, persistência dos coxins fetais, falanges distais dos polegares alargadas e pés planos. A baixa estatura e a microcefalia foi observada em 80% e 76% dos casos, respectivamente. As principais características craniofaciais observadas foram: fronte proeminente (86%), ponte nasal larga (60%), hipertelorismo (70%), sobrancelhas espessas e arqueadas (96%) cílios longos em 93%, prega epicântica (76%), fissura palpebral infra vertidas (76%), abertura bucal estreita (93%), retrognatismo (76 %), sorriso característico em 100%, palato alto e estreito (93%), anomalias dentárias (83%). Outras anomalias identificadas foram: estrabismo, erros de refração, obstrução do canal lacrimal, háluces e polegares alargados, angulação de polegares, anomalias do pavilhão auricular (rotação/posição/tamanho/forma), angulação do hálux, clinodactilia, sobreposição dos pododáctilos, falanges distais alargadas de outros dedos, marcha rígida, hipotonia, sopro cardíaco, cardiopatia congênita, criptoquidia, hemangioma plano e hipertricose. Uma paciente apresentou translocação recíproca de novo 46, XX, t (2; 16)(q36.3; p13.3). CONCLUSÕES: A raridade da SRT e o amplo espectro das manifestações clínicas pode atrasar o diagnóstico clínico. A média da idade ao diagnóstico dos nossos pacientes com SRT foi de três anos e oito meses. Todas as crianças devem receber avaliação por geneticista pediátrico, cardiologista, oftalmologista, neuropediatra, e odontopediatra / INTRODUCTION: Rubinstein-Taybi syndrome (RTS) is a rare genetic disorder characterized by distinctive craniofacial dysmorphisms, broad thumbs and toes and mental and statural deficiency. The prevalence of RTS has been estimated to be 1 in 125000 to 1: 330000 live births. RTS usually occurs sporadically although it can be inherited as an autosomal dominant disorder. The diagnosis of RTS is primarily based on clinical features. OBJECTIVES: We performed a clinical and cytogenetic assay in a group of 30 Brazilian RTS patients. We also decribed the frequencies of facial dysmorphisms and multiple malformations. METHODS: In this observational retrospective and prospective study, the patients were followed from August 2005 to June 2009. Chromosomal analysis was performed by G-banding karyotype. RESULTS: Most of the patients were female (60%).The following abnormalities were present in all of the patients: delayed psychomotor development, beaked nose, proeminent collumel, typical facies, broad thumbs and toes, flat feet, joint laxity, feeding problems during the childhood, and finger pads. Short stature was present in 80%, and microcephalia in 76% of the cases, respectively. Main craniofacial characteristics are frontal bossing (86%), wide nasal bridge (60%), ocular hyperthelorism (70%), high arched eyebrows (96%), long eyelashes (93%), epicathal folds (76%), downslanting palpebral fissures (76%), small opening of the mouth (93%), retrognathism (76%), grimacing smile (100%), high arched palate (93%), and dental anomalies (83%). Other findings were: strabism, refractive error, lacrimal obstruction, wide thumb and halux, angulated thumbs, external ears anomalies (rotation, implantation and morfology), angulated halux, clinodactyly, crowded toes, broad distal falanges of other fingers, stiff gait, hipotonia, cardiac murmur, congenital heart defect, undescendent testis, hypertrichosis, and hemangioma. One female patient has found to have a reciprocal de novo translocation t(2;16)(q36.3;p13.3) on G-banding karyotype CONCLUSIONS: The rarity of RTS and the wide spectrum of clinical manifestations, may delay the clinical diagnosis of RTS. The average age at the diagnosis of our patients was 3 years and 8 months. All children of RTS should receive an evaluation by a pediatric geneticist, cardiologist, ophthalmologist, pediatric neurologist, and pediatric dentist

A Síndrome de Rubinstein-Taybi (RTSs) é uma doença rara de herança autossômica dominante, caracterizada por dismorfismos craniofaciais, polegares e háluces alargados, deficiência intelectual e de crescimento. RTSs tem sido associada com mutações no gene CREBBP (CBP) e mutações menos frequentes no gene EP300 que foram descritas em oito indivíduos. CBP e p300 possuem alta homologia e são extremamente importantes em várias vias de sinalização, principalmente como coativadores de transcrição e na acetilação das histonas. Nosso estudo baseou-se na análise de alterações moleculares por sequenciamento direto do CBP, FISH e array-CGH em 20 pacientes com RTSs. Dos 20 pacientes avaliados por sequenciamento direto foram identificadas oito alterações moleculares, dentre estas, seis são alterações moleculares novas as quais não foram descritas na literatura, são elas: i) duas deleções (p.M747fs STOP830 e p.G1011fs STOP1021) ii) duas alterações do tipo nonsense (p.Arg1341X, p.Arg1498X) iii) três do tipo missense (p.Arg1907Trp, p.Leu604Pro e p.His1291Arg). Também identificamos um polimorfismo de único nucleotídeo (SNP) (rs115594471/ c.5874CT). Dois pacientes apresentaram deleção do gene CBP em um dos alelos, identificado pelo método array-CGH. Outro, apresentou uma translocação aparentemente equilibrada t(2;16), cuja análise subsequente com FISH revelou uma quebra na região do CBP. Neste trabalho, a taxa de detecção de alteração molecular no CBP por sequenciamento direto foi de 40% (08/20). Porém, a taxa de detecção das alterações moleculares no CBP foi de 55% (11/20), considerando a combinação das diferentes técnicas utilizadas (FISH, sequenciamento direto e array-CGH). Não houve correlação genótipo-fenótipo, exceto por uma maior frequência da presença de epicanto nos pacientes com alteração no CBP. Os resultados obtidos neste trabalho servem como o diagnóstico molecular para os pacientes com RTSs atendidos no Ambulatório do Laboratório de investigação Médica 001 (ALIM 001) do Instituto da Criança - FMUSP, contribuindo para uma melhor orientação médica, como também para realização do aconselhamento genético às famílias / Rubinstein-Taybi syndrome (RTSs) is a rare autosomal dominant disease characterized by craniofacial dysmorphisms, broad thumbs and toes, mental and growth deficiency. RTS has been associated with CREBBP (CBP) gene mutations and less frequently with mutations in EP300 gene, which have been reported in eight individuals. CBP and p300 have high homology and are extremely important in many signaling pathways especially as transcriptional coactivators and histone acetylation. Our study was based on the alteration analysis by direct sequencing of the CBP, by FISH and array-CGH in 20 RTSs patients. We identified eight molecular alterations in 20 RTSs patients evaluated by direct sequencing: i) two deletions (p.M747fs STOP830 and p.G1011fs STOP1021) ii) two nonsense alterations (p.Arg1341X and p.Arg1498X) iii) Three missense alteration (p.Arg1907Trp, p.Leu604Pro and p.His1291Arg). Single-nucleotide polymorphism were also identified (rs115594471 / c.5874CT), and six of these are new molecular alterations, not described in literature. Two RTSs patients studied had CBP gene deletion in one allele, identified by array-CGH method. Other patient, presented with apparent balanced translocation t(2;16) in which the subsequent analysis using FISH, showed a break in region of CBP. In this work, the rate of detection of molecular alteration in CBP by direct sequencing in RTSs patient was 40.0% (08/20). However, the rate of detection of molecular alteration in CBP was 55.0% (11/20), considering the combination of different techniques (FISH, direct sequencing and array-CGH. No significant correlation could be established in this study between the different types of mutations and genotype-phenotype of RTSs patients, except a higher frequency of the presence of epicanthus in the RTS patients with alteration in the CBP. The results of this study serve as a molecular diagnosis for RTSs patients treated at the Ambulatory of the Medical Investigation Laboratory 001 (ALIM 001) of the Instituto da Criança - FMUSP, and this contributes to better clinical management, such as making an appropriate genetic counseling for families

Thesis (Ph.D. in Neuroscience) -- University of Colorado Denver, 2008. / Typescript. Includes bibliographical references (leaves 110-125). Online version available via ProQuest Digital Dissertations.

p53, known as the “guardian of the genome”, is the most well-characterized tumor suppressor gene. The central role of p53 is to prevent genome instability. p53 is the central node in an incredibly elaborate genome defense network for receiving various input stress signals and controlling diverse cellular responses. The final output of this network is determined not only by the p53 protein itself, but also by other p53 cooperating proteins. p300 and CBP (CREB-Binding Protein) act as multifunctional regulators of p53 via acetylase and ubiquitin ligase activities. Prior work in vitro has shown that the N-terminal 595 aa of p300 encode both generic ubiquitin ligase (E3) and p53-directed E4 functions. Analysis of p300 or CBP-deficient cells revealed that both coactivators were required for endogenous p53 polyubiquitination and the normally rapid turnover of p53 in unstressed cells. Unexpectedly, p300/CBP ubiquitin ligase activities were absent in nuclear extracts and exclusively cytoplasmic. In the nucleus, CBP and p300 exhibited differential regulation of p53 gene target expression, C-terminal acetylation, and biologic response after DNA damage. p300 activated, and CBP repressed, PUMA expression, correlating with activating acetylation of p53 C-terminal lysines by p300, and a repressive acetylation of p53 lysine-320 induced by CBP. Consistent with their gene expression effects, CBP deficiency augmented, and p300 deficiency blocked, apoptosis after doxorubicin treatment. Subcellular compartmentalization of p300/CBP’s ubiquitination and transcription activities reconciles seemingly opposed functions—cytoplasmic p300/CBP E4 activities ubiquitinate and destabilize p53, while nuclear p300/CBP direct p53 acetylation, target gene activation, and biological outcome after genotoxic stress. p53 is a prominent tumor suppressor gene and it is mutated in more than 50% of human tumors. Reactivation of endogenous p53 is one therapeutic avenue to stop cancer cell growth. In this thesis, we have identified S5as a critical regulator of p53 degradation and activity. S5a is a non-ATPase subunit in the 19S regulatory particle of the 26S proteasome. Our preliminary data indicates that S5a is required for p53 instability and is a negative regulator of p53 tranactivation. As a negative regulator of p53, S5a may therefore also represent a new target for cancer drug development against tumors that specifically maintain wild type p53.

La génération des cellules hématopoïétiques, aussi connue sous le nom d'hématopoïèse, est contrôlée par l’activité conjuguée de facteurs de transcription lignée-spécifiques permettant l’expression, en temps et lieu, de gènes spécifiques nécessaires pour le développement cellulaire. Dans le cadre de notre étude, nous avons étudié les facteurs de transcription KLF2 et KLF4 qui jouent des rôles cruciaux dans la formation des lymphocytes B et T. KLF2 et KLF4 activent la transcription de gènes spécifiques via leur interaction avec le co-activateur (CBP). Leurs interactions avec CBP requièrent le domaine de transactivation (TAD) qui est localisé dans la région N-terminal des facteurs KLF2 et KLF4. Des études préalables ont montré que des domaines TAD sont aussi présents chez la protéine suppresseur de tumeur p53 et que ces domaines sont requis pour les interactions entre la protéine p53 et le co-activateur CBP. Récemment, plusieurs structures des TADs de p53 en complexe avec les domaines TAZ2 et KIX de CBP ont permis de démontrer que ces TADs sont de nature acide et contiennent un motif ΦΧΧΦΦ crucial pour la formation des interactions. De plus, il s’avère que ces TADs sont similaires aux TADs de KLF2 et KLF4. L’étude présentée dans ce mémoire relate la caractérisation structurelle et fonctionnelle des interactions formées par les facteurs de transcription KLF2 et KLF4 avec leur partenaire d'interaction, CBP, pour activer la transcription de gènes spécifiques. Nos analyses ont été faites en utilisant différentes techniques telles que le titrage calorimétrique isotherme (ITC), la résonance magnétique nucléaire (RMN) ainsi que des expériences de transactivation chez la levure. Notre étude permet une meilleure compréhension des rôles opposés mais complémentaires qu'ont les protéines KLF2 et KLF4 au cours du développement et de la différentiation des lymphocytes B et T en plus de fournir les détails mécanistiques à la base de leurs interactions. Ces informations seront potentiellement utiles pour le développement d'outils à des fins thérapeutiques dans le cadre des leucémies, notamment. / Hematopoietic development is regulated through a combinatorial interplay between lineage-specific activators and the general transcription factors that enables cell-specific patterns of gene expression. In this study, the transcription factors KLF2 and KLF4 play crucial roles in lymphocytes B and T development by activating transcription of specific genes through interactions with the co-activator (CBP). These interactions involve the transactivation domains (TAD) localized in the N-terminal region of KLF2 and KLF4 factors. Previous studies have shown that TADs are also found in the tumor suppressor protein p53 and these TADs are responsible for the interactions between the p53 protein and the coactivator CBP. Recently, several structures of p53TADs in complex with the TAZ2 and KIX domains of CBP have shown that these TADs are acidic and possess a ΦΧΧΦΦ motif crucial for the formation of the interaction. Interestingly, these TADs are similar to the ones found on KLF2 and KLF4. This thesis provides a structural and functional characterization of the interactions formed by the transcription factors KLF2 and KLF4, which have opposing roles, and competes for the same interacting partner CBP to activate transcription. The analysis is done using isothermal titration calorimetry (ITC), nuclear magnetic resonance (NMR) spectroscopy and a yeast activation assay. This study brings a greater understanding on the opposing roles yet complementary of KLF2 and KLF4 proteins involved in B and T lymphocytes specific lineages selection and also provides information for potential therapeutic research regarding disease such as leukemia.