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1.
Artigo em Inglês | MEDLINE | ID: mdl-38872284

RESUMO

OBJECTIVES: To evaluate the efficacy of ChatGPT 4 (GPT-4) in delivering genetic information about BRCA1, HFE, and MLH1, building on previous findings with ChatGPT 3.5 (GPT-3.5). To focus on assessing the utility, limitations, and ethical implications of using ChatGPT in medical settings. MATERIALS AND METHODS: A structured survey was developed to assess GPT-4's clinical value. An expert panel of genetic counselors and clinical geneticists evaluated GPT-4's responses to these questions. We also performed comparative analysis with GPT-3.5, utilizing descriptive statistics and using Prism 9 for data analysis. RESULTS: The findings indicate improved accuracy in GPT-4 over GPT-3.5 (P < .0001). However, notable errors in accuracy remained. The relevance of responses varied in GPT-4, but was generally favorable, with a mean in the "somewhat agree" range. There was no difference in performance by disease category. The 7-question subset of the Bot Usability Scale (BUS-15) showed no statistically significant difference between the groups but trended lower in the GPT-4 version. DISCUSSION AND CONCLUSION: The study underscores GPT-4's potential role in genetic education, showing notable progress yet facing challenges like outdated information and the necessity of ongoing refinement. Our results, while showing promise, emphasizes the importance of balancing technological innovation with ethical responsibility in healthcare information delivery.

2.
J Am Heart Assoc ; 13(8): e034048, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38591341

RESUMO

BACKGROUND: We aimed to describe the frequency and yield of genetic testing in supravalvar aortic stenosis (SVAS) following negative evaluation for Williams-Beuren syndrome (WS). METHODS AND RESULTS: This retrospective cohort study included patients with SVAS at our institution who had a negative evaluation for WS from May 1991 to September 2021. SVAS was defined as (1) peak supravalvar velocity of ≥2 meters/second, (2) sinotubular junction or ascending aortic Z score <-2.0, or (3) sinotubular junction Z score <-1.5 with family history of SVAS. Patients with complex congenital heart disease, aortic valve disease as the primary condition, or only postoperative SVAS were excluded. Genetic testing and diagnoses were reported. Of 162 patients who were WS negative meeting inclusion criteria, 61 had genetic testing results available (38%). Chromosomal microarray had been performed in 44 of 61 and was nondiagnostic for non-WS causes of SVAS. Sequencing of 1 or more genes was performed in 47 of 61. Of these, 39 of 47 underwent ELN sequencing, 20 of 39 (51%) of whom had a diagnostic variant. Other diagnoses made by gene sequencing were Noonan syndrome (3 PTPN11, 1 RIT1), Alagille syndrome (3 JAG1), neurofibromatosis (1 NF1), and homozygous familial hypercholesterolemia (1 LDLR1). Overall, sequencing was diagnostic in 29 of 47 (62%). CONCLUSIONS: When WS is excluded, gene sequencing for SVAS is high yield, with the highest yield for the ELN gene. Therefore, we recommend gene sequencing using a multigene panel or exome analysis. Hypercholesterolemia can also be considered in individuals bearing the stigmata of this disease.


Assuntos
Estenose Aórtica Supravalvular , Síndrome de Williams , Humanos , Síndrome de Williams/diagnóstico , Síndrome de Williams/genética , Síndrome de Williams/cirurgia , Estenose Aórtica Supravalvular/diagnóstico , Estenose Aórtica Supravalvular/genética , Estenose Aórtica Supravalvular/congênito , Estudos Retrospectivos , Testes Genéticos , Aorta
3.
bioRxiv ; 2023 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-38076902

RESUMO

Genetic disorders are complex and can greatly impact an individual's health and well-being. In this study, we assess the ability of ChatGPT, a language model developed by OpenAI, to answer questions related to three specific genetic disorders: BRCA1, MLH1, and HFE. ChatGPT has shown it can supply articulate answers to a wide spectrum of questions. However, its ability to answer questions related to genetic disorders has yet to be evaluated. The aim of this study is to perform both quantitative and qualitative assessments of ChatGPT's performance in this area. The ability of ChatGPT to provide accurate and useful information to patients was assessed by genetic experts. Here we show that ChatGPT answered 64.7% of the 68 genetic questions asked and was able to respond coherently to complex questions related to the three genes/conditions. Our results reveal that ChatGPT can provide valuable information to individuals seeking information about genetic disorders, however, it still has some limitations and inaccuracies, particularly in understanding human inheritance patterns. The results of this study have implications for both genomics and medicine and can inform future developments in this area. AI platforms, like ChatGPT, have significant potential in the field of genomics. As these technologies become integrated into consumer-facing products, appropriate oversight is required to ensure accurate and safe delivery of medical information. With such oversight and training specifically for genetic information, these platforms could have the potential to augment some clinical interactions.

4.
JCI Insight ; 6(5)2021 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-33497361

RESUMO

Mutations in EPAS1, encoding hypoxia-inducible factor-2α (HIF-2α), were previously identified in a syndrome of multiple paragangliomas, somatostatinoma, and polycythemia. HIF-2α, when dimerized with HIF-1ß, acts as an angiogenic transcription factor. Patients referred to the NIH for new, recurrent, and/or metastatic paraganglioma or pheochromocytoma were confirmed for EPAS1 gain-of-function mutation; imaging was evaluated for vascular malformations. We evaluated the Epas1A529V transgenic syndrome mouse model, corresponding to the mutation initially detected in the patients (EPAS1A530V), for vascular malformations via intravital 2-photon microscopy of meningeal vessels, terminal vascular perfusion with Microfil silicate polymer and subsequent intact ex vivo 14T MRI and micro-CT, and histologic sectioning and staining of the brain and identified pathologies. Further, we evaluated retinas from corresponding developmental time points (P7, P14, and P21) and the adult dura via immunofluorescent labeling of vessels and confocal imaging. We identified a spectrum of vascular malformations in all 9 syndromic patients and in all our tested mutant mice. Patient vessels had higher variant allele frequency than adjacent normal tissue. Veins of the murine retina and intracranial dura failed to regress normally at the expected developmental time points. These findings add vascular malformation as a new clinical feature of EPAS1 gain-of-function syndrome.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Tumores Neuroendócrinos/genética , Policitemia/genética , Malformações Vasculares/genética , Adolescente , Adulto , Animais , Feminino , Mutação com Ganho de Função , Regulação da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Adulto Jovem
5.
Am J Hum Genet ; 108(1): 8-15, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33417889

RESUMO

The delineation of disease entities is complex, yet recent advances in the molecular characterization of diseases provide opportunities to designate diseases in a biologically valid manner. Here, we have formalized an approach to the delineation of Mendelian genetic disorders that encompasses two distinct but inter-related concepts: (1) the gene that is mutated and (2) the phenotypic descriptor, preferably a recognizably distinct phenotype. We assert that only by a combinatorial or dyadic approach taking both of these attributes into account can a unitary, distinct genetic disorder be designated. We propose that all Mendelian disorders should be designated as "GENE-related phenotype descriptor" (e.g., "CFTR-related cystic fibrosis"). This approach to delineating and naming disorders reconciles the complexity of gene-to-phenotype relationships in a simple and clear manner yet communicates the complexity and nuance of these relationships.


Assuntos
Doenças Genéticas Inatas/diagnóstico , Doenças Genéticas Inatas/genética , Genômica/métodos , Fibrose Cística/diagnóstico , Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Genótipo , Humanos , Mutação/genética , Fenótipo
6.
J Microsc ; 283(1): 9-20, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33482682

RESUMO

In pathology protocols, a tissue block, such as one containing a mouse brain or a biopsy sample from a patient, can produce several hundred thin sections. Substantial time may be required to analyse all sections. In cases of uncertainty regarding which sections to focus on, noninvasive scout imaging of intact blocks can help in guiding the pathology procedure. The scouting step is ideally done in a time window of minutes without special sample preparation that may interfere with the pathology procedures. The challenge is to obtain some visibility of unstained tissue structures at sub-10 µm resolution. We explored a novel x-ray tomosynthesis method as a way to maximise contrast-to-noise ratio, a determinant of tissue visibility. It provided a z-stack of thousands of images at 7.3 µm resolution (10% contrast, half-period of 68.5 line pairs/mm), in scans of 5-15 minutes. When compared with micro-CT scans, the straight-line tomosynthesis scan did not need to rotate the sample, which allowed flat samples, such as paraffin blocks, to be kept as close as possible to the x-ray source. Thus, given the same hardware, scan time and resolution, this mode maximised the photon flux density through the sample, which helped in maximising the contrast-to-noise ratio. The tradeoff of tomosynthesis is incomplete 3D information. The microtomosynthesis scanner has scanned 110 unstained human and animal tissue samples as part of their respective pathology protocols. In all cases, the z-stack of images showed tissue structures that guided sectioning or provided correlative structural information. We describe six examples that presented different levels of visibility of soft tissue structures. Additionally, in a set of coronary artery samples from an HIV patient donor, microtomosynthesis made a new discovery of isolated focal calcification in the internal elastic lamina of coronary wall, which was the onset of medial calcific sclerosis in the arteries.


A microscopy version of the imaging method for 3D luggage screening has been adapted to image unstained pathology samples. Pathology tests of tissue samples are used for clinical diagnosis and for biomedical research. The tissue samples are often embedded in paraffin blocks and sectioned into many thin slices, which are then stained with the appropriate agents for light microscopy. Since each tissue block can produce several hundred thin sections, much time and labour is required to analyse all sections. Noninvasive scout imaging of intact blocks can help in guiding the pathology procedure. The scouting step is ideally done in a time window of minutes without special sample preparation that may interfere with the pathology procedures. The challenge is to obtain some visibility of unstained tissue structures at sufficient resolution. X-ray imaging is a promising tool to meet the challenge since x-rays can penetrate thick samples that are opaque to visible light. With x-ray imaging, a determinant of tissue visibility is the flux density of photons that illuminate the sample. We explored a novel x-ray tomosynthesis method as a way to maximise this factor. It provided a stack of thousands of cross-sectional images at 7.3 µm resolution (half-period of 68.5 line pairs/mm) in scans of 5-15 minutes. When compared with micro-CT scans (a widely used laboratory technology), this method did not need to rotate the sample, which allowed flat samples such as paraffin blocks to be kept as close as possible to the x-ray source. Thus, given the same hardware, scan time and resolution, this method maximised the photon flux density through the sample, which helped in improving the visibility of unstained tissue under x-ray. The tradeoff of the method is incomplete 3D information. Over 100 unstained human and animal tissue samples have been scanned with this method as part of their respective pathology protocols. In all cases, the stack of cross-sectional images showed tissue structures that guided pathology analysis or provided correlative structural information. We describe six examples that presented different levels of tissue visibility. Additionally, in a set of coronary artery samples from an HIV patient donor, microtomosynthesis made a new discovery of isolated focal calcification in the internal elastic lamina of coronary wall, which was the onset of medial calcific sclerosis in the arteries.


Assuntos
Infecções por HIV , Imageamento Tridimensional , Animais , Humanos , Camundongos , Radiografia , Calcificação Vascular , Microtomografia por Raio-X , Raios X
7.
Environ Health ; 19(1): 65, 2020 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-32513280

RESUMO

BACKGROUND: Pesticide exposure during susceptible windows and at certain doses are linked to numerous birth defects. Early experimental evidence suggests an association between active ingredients in pesticides and holoprosencephaly (HPE), the most common malformation of the forebrain in humans (1 in 250 embryos). No human studies to date have examined the association. This study investigated pesticides during multiple windows of exposure and fetal risk for HPE. It is hypothesized that pre-conception and early pregnancy, the time of brain development in utero, are the most critical windows of exposure. METHODS: A questionnaire was developed for this retrospective case-control study to estimate household, occupational, and environmental pesticide exposures. Four windows of exposure were considered: preconception, early, mid and late pregnancy. Cases were identified through the National Human Genome Research Institute's ongoing clinical studies of HPE. Similarly, controls were identified as children with Williams-Beuren syndrome, a genetic syndrome also characterized by congenital malformations, but etiologically unrelated to HPE. We assessed for differences in odds of exposures to pesticides between cases and controls. RESULTS: Findings from 91 cases and 56 controls showed an increased risk for HPE with reports of maternal exposure during pregnancy to select pesticides including personal insect repellants (adjusted odds ratio (aOR) 2.89, confidence interval (CI): 0.96-9.50) and insecticides and acaricides for pets (aOR 3.84, CI:1.04-16.32). Exposure to household pest control products during the preconception period or during pregnancy was associated with increased risk for HPE (aOR 2.60, OR: 0.84-8.68). No associations were found for occupational exposures to pesticides during pregnancy (aOR: 1.15, CI: 0.11-11.42), although exposure rates were low. Higher likelihood for HPE was also observed with residency next to an agricultural field (aOR 3.24, CI: 0.94-12.31). CONCLUSIONS: Observational findings are consistent with experimental evidence and suggest that exposure to personal, household, and agricultural pesticides during pregnancy may increase risk for HPE. Further investigations of gene by environment interactions are warranted.


Assuntos
Exposição Ambiental/efeitos adversos , Holoprosencefalia/epidemiologia , Praguicidas/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Holoprosencefalia/induzido quimicamente , Humanos , Masculino , Exposição Materna/efeitos adversos , Exposição Ocupacional/efeitos adversos , Gravidez/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Estudos Retrospectivos , Fatores de Risco , Estados Unidos/epidemiologia , Adulto Jovem
8.
J Clin Invest ; 130(8): 4167-4181, 2020 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-32369445

RESUMO

There are more than 7000 described rare diseases, most lacking specific treatment. Autosomal-dominant hyper-IgE syndrome (AD-HIES, also known as Job's syndrome) is caused by mutations in STAT3. These patients present with immunodeficiency accompanied by severe nonimmunological features, including skeletal, connective tissue, and vascular abnormalities, poor postinfection lung healing, and subsequent pulmonary failure. No specific therapies are available for these abnormalities. Here, we investigated underlying mechanisms in order to identify therapeutic targets. Histological analysis of skin wounds demonstrated delayed granulation tissue formation and vascularization during skin-wound healing in AD-HIES patients. Global gene expression analysis in AD-HIES patient skin fibroblasts identified deficiencies in a STAT3-controlled transcriptional network regulating extracellular matrix (ECM) remodeling and angiogenesis, with hypoxia-inducible factor 1α (HIF-1α) being a major contributor. Consistent with this, histological analysis of skin wounds and coronary arteries from AD-HIES patients showed decreased HIF-1α expression and revealed abnormal organization of the ECM and altered formation of the coronary vasa vasorum. Disease modeling using cell culture and mouse models of angiogenesis and wound healing confirmed these predicted deficiencies and demonstrated therapeutic benefit of HIF-1α-stabilizing drugs. The study provides mechanistic insights into AD-HIES pathophysiology and suggests potential treatment options for this rare disease.


Assuntos
Matriz Extracelular/metabolismo , Síndrome de Job/metabolismo , Neovascularização Fisiológica , Pele/metabolismo , Cicatrização , Ferimentos e Lesões/metabolismo , Animais , Matriz Extracelular/genética , Matriz Extracelular/patologia , Feminino , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Síndrome de Job/genética , Síndrome de Job/patologia , Masculino , Camundongos , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Pele/irrigação sanguínea , Pele/patologia , Ferimentos e Lesões/genética , Ferimentos e Lesões/patologia
9.
Neurol Genet ; 6(3): e414, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32337341

RESUMO

OBJECTIVE: To investigate the effect of somatic, postzygotic, gain-of-function mutation of Endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1) encoding hypoxia-inducible factor-2α (HIF-2α) on posterior fossa development and spinal dysraphism in EPAS1 gain-of-function syndrome, which consists of multiple paragangliomas, somatostatinoma, and polycythemia. METHODS: Patients referred to our institution for evaluation of new, recurrent, and/or metastatic paragangliomas/pheochromocytoma were confirmed for EPAS1 gain-of-function syndrome by identification of the EPAS1 gain-of-function mutation in resected tumors and/or circulating leukocytes. The posterior fossa, its contents, and the spine were evaluated retrospectively on available MRI and CT images of the head and neck performed for tumor staging and restaging. The transgenic mouse model underwent Microfil vascular perfusion and subsequent intact ex vivo 14T MRI and micro-CT as well as gross dissection, histology, and immunohistochemistry to assess the role of EPAS1 in identified malformations. RESULTS: All 8 patients with EPAS1 gain-of-function syndrome demonstrated incidental posterior fossa malformations-one Dandy-Walker variant and 7 Chiari malformations without syringomyelia. These findings were not associated with a small posterior fossa; rather, the posterior fossa volume exceeded that of its neural contents. Seven of 8 patients demonstrated spinal dysraphism; 4 of 8 demonstrated abnormal vertebral segmentation. The mouse model similarly demonstrated features of neuraxial dysraphism, including cervical myelomeningocele and spinal dysraphism, and cerebellar tonsil displacement through the foramen magnum. Histology and immunohistochemistry demonstrated incomplete mesenchymal transition in the mutant but not the control mouse. CONCLUSIONS: This study characterized posterior fossa and spinal malformations seen in EPAS1 gain-of-function syndrome and suggests that gain-of-function mutation in HIF-2α results in improper mesenchymal transition.

10.
Am J Med Genet A ; 182(5): 1008-1020, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32077592

RESUMO

Williams-Beuren syndrome (WBS) is a multisystem disorder caused by a hemizygous deletion on 7q11.23 encompassing 26-28 genes. An estimated 2-5% of patients have "atypical" deletions, which extend in the centromeric and/or telomeric direction from the WBS critical region. To elucidate clinical differentiators among these deletion types, we evaluated 10 individuals with atypical deletions in our cohort and 17 individuals with similarly classified deletions previously described in the literature. Larger deletions in either direction often led to more severe developmental delays, while deletions containing MAGI2 were associated with infantile spasms and seizures in patients. In addition, head size was notably smaller in those with centromeric deletions including AUTS2. Because children with atypical deletions were noted to be less socially engaged, we additionally sought to determine how atypical deletions relate to social phenotypes. Using the Social Responsiveness Scale-2, raters scored individuals with atypical deletions as having different social characteristics to those with typical WBS deletions (p = .001), with higher (more impaired) scores for social motivation (p = .005) in the atypical deletion group. In recognizing these distinctions, physicians can better identify patients, including those who may already carry a clinical or FISH WBS diagnosis, who may benefit from additional molecular evaluation, screening, and therapy. In addition to the clinical findings, we note mild endocrine findings distinct from those typically seen in WBS in several patients with telomeric deletions that included POR. Further study in additional telomeric deletion cases will be needed to confirm this observation.


Assuntos
Cromossomos Humanos Par 7/genética , Neoplasia Endócrina Múltipla/genética , Transtornos do Neurodesenvolvimento/genética , Síndrome de Williams/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Deleção Cromossômica , Feminino , Cabeça/anormalidades , Cabeça/fisiopatologia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Neoplasia Endócrina Múltipla/epidemiologia , Neoplasia Endócrina Múltipla/fisiopatologia , Transtornos do Neurodesenvolvimento/epidemiologia , Transtornos do Neurodesenvolvimento/fisiopatologia , Tamanho do Órgão/genética , Fenótipo , Síndrome de Williams/epidemiologia , Síndrome de Williams/fisiopatologia , Adulto Jovem
11.
J Pediatr Hematol Oncol ; 41(2): 133-136, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30028825

RESUMO

Identification of patients with cancer predisposition syndromes (CPSs) can provide vital information to guide care of an existing cancer, survey for future malignancy, and counsel families. The same underlying mutation responsible for a CPS may also result in other phenotypic abnormalities amenable to therapeutic intervention. The purpose of this study was to examine patients followed in our multidisciplinary CPS clinic to determine the prevalence and scope of medical and psychosocial needs. Data from a baseline evaluation of a single-center patient registry was reviewed. Eligible patients included those with a known or suspected CPS. Over 3 years, 73 patients consented and had successful follow-up. Utilization rate of special therapies, defined as speech therapy, occupational therapy, and/or physical therapy, in the CPS population was 50.7%, significantly higher than a representative sample of children with special needs. Prevalence of 504/IEP (Individualized Education Program) utilization was 20.5%. Patients with CPSs have a high prevalence of medical and psychosocial needs beyond their risk for cancer, for which early screening for necessary interventions should be offered to maximize the patient's developmental potential. Future research is needed to further define the developmental and cognitive phenotypes of these syndromes, and to evaluate the effectiveness of subsequent interventions.


Assuntos
Institutos de Câncer , Predisposição Genética para Doença/psicologia , Sistema de Registros , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Neoplasias/epidemiologia , Neoplasias/genética , Neoplasias/psicologia , Neoplasias/terapia , Prevalência , Psicologia
12.
Proc Natl Acad Sci U S A ; 113(24): 6773-8, 2016 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-27247394

RESUMO

Cantu syndrome (CS) is caused by gain-of-function (GOF) mutations in genes encoding pore-forming (Kir6.1, KCNJ8) and accessory (SUR2, ABCC9) KATP channel subunits. We show that patients with CS, as well as mice with constitutive (cGOF) or tamoxifen-induced (icGOF) cardiac-specific Kir6.1 GOF subunit expression, have enlarged hearts, with increased ejection fraction and increased contractility. Whole-cell voltage-clamp recordings from cGOF or icGOF ventricular myocytes (VM) show increased basal L-type Ca(2+) current (LTCC), comparable to that seen in WT VM treated with isoproterenol. Mice with vascular-specific expression (vGOF) show left ventricular dilation as well as less-markedly increased LTCC. Increased LTCC in KATP GOF models is paralleled by changes in phosphorylation of the pore-forming α1 subunit of the cardiac voltage-gated calcium channel Cav1.2 at Ser1928, suggesting enhanced protein kinase activity as a potential link between increased KATP current and CS cardiac pathophysiology.


Assuntos
Canais de Cálcio Tipo L/metabolismo , Cardiomegalia/metabolismo , Ventrículos do Coração/metabolismo , Hipertricose/metabolismo , Canais KATP/metabolismo , Contração Miocárdica , Miócitos Cardíacos/metabolismo , Osteocondrodisplasias/metabolismo , Receptores de Sulfonilureias/metabolismo , Animais , Canais de Cálcio Tipo L/genética , Sinalização do Cálcio/efeitos dos fármacos , Sinalização do Cálcio/genética , Cardiomegalia/genética , Cardiomegalia/patologia , Cardiomegalia/fisiopatologia , Feminino , Ventrículos do Coração/patologia , Ventrículos do Coração/fisiopatologia , Humanos , Hipertricose/genética , Hipertricose/patologia , Hipertricose/fisiopatologia , Isoproterenol/farmacologia , Canais KATP/genética , Masculino , Camundongos , Camundongos Transgênicos , Miócitos Cardíacos/patologia , Osteocondrodisplasias/genética , Osteocondrodisplasias/patologia , Osteocondrodisplasias/fisiopatologia , Receptores de Sulfonilureias/genética
14.
J Biol Chem ; 278(20): 18491-8, 2003 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-12626514

RESUMO

Elastic fiber assembly is a complicated process involving multiple different proteins and enzyme activities. However, the specific protein-protein interactions that facilitate elastin polymerization have not been defined. To identify domains in the tropoelastin molecule important for the assembly process, we utilized an in vitro assembly model to map sequences within tropoelastin that facilitate its association with fibrillin-containing microfibrils in the extracellular matrix. Our results show that an essential assembly domain is located in the C-terminal region of the molecule, encoded by exons 29-36. Fine mapping studies using an exon deletion strategy and synthetic peptides identified the hydrophobic sequence in exon 30 as a major functional element in this region and suggested that the assembly process is driven by the propensity of this sequence to form beta-sheet structure. Tropoelastin molecules lacking the C-terminal assembly domain expressed as transgenes in mice did not assemble nor did they interfere with assembly of full-length normal mouse elastin. In addition to providing important information about elastin assembly in general, the results of this study suggest how removal or alteration of the C terminus through stop or frameshift mutations might contribute to the elastin-related diseases supravalvular aortic stenosis and cutis laxa.


Assuntos
Elastina/química , Tropoelastina/química , Alelos , Aminoácidos/química , Amiloide/química , Animais , Western Blotting , Bovinos , Corantes/farmacologia , Vermelho Congo/farmacologia , DNA Complementar/metabolismo , Éxons , Matriz Extracelular/metabolismo , Mutação da Fase de Leitura , Deleção de Genes , Camundongos , Camundongos Transgênicos , Microscopia Eletrônica , Microscopia de Fluorescência , Mutação , Peptídeos/química , Testes de Precipitina , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transfecção , Tropoelastina/metabolismo
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