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1.
Nucleic Acids Res ; 49(4): 2255-2265, 2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33533913

RESUMO

Interferon regulatory factor 4 (IRF4) is a key transcription factor (TF) in the regulation of immune cells, including B and T cells. It acts by binding DNA as both a homodimer and, in conjunction with other TFs, as a heterodimer. The choice of homo and heterodimeric/ DNA interactions is a critical aspect in the control of the transcriptional program and cell fate outcome. To characterize the nature of this interaction in the homodimeric complex, we have determined the crystal structure of the IRF4/ISRE homodimeric complex. We show that the complex formation is aided by a substantial DNA deformation with co-operative binding achieved exclusively through protein-DNA contact. This markedly contrasts with the heterodimeric form where DNA bound IRF4 is shown to physically interact with PU.1 TF to engage EICE1. We also show that the hotspot residues (Arg98, Cys99 and Asn102) contact both consensus and non-consensus sequences with the L1 loop exhibiting marked flexibility. Additionally, we identified that IRF4L116R, a mutant associated with chronic lymphocytic leukemia, binds more robustly to DNA thereby providing a rationale for the observed gain of function. Together, we demonstrate key structural differences between IRF4 homo and heterodimeric complexes, thereby providing molecular insights into IRF4-mediated transcriptional regulation.


Assuntos
DNA/química , Fatores Reguladores de Interferon/química , DNA/metabolismo , Dimerização , Mutação com Ganho de Função , Humanos , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Leucemia Linfocítica Crônica de Células B/genética , Modelos Moleculares , Ligação Proteica , Domínios Proteicos , Multimerização Proteica , Proteínas Proto-Oncogênicas/química , Transativadores/química
2.
Nat Commun ; 12(1): 704, 2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514736

RESUMO

p53 mutations with single amino acid changes in cancer often lead to dominant oncogenic changes. Here, we have developed a mouse model of gain-of-function (GOF) p53-driven lung cancer utilizing conditionally active LSL p53-R172H and LSL K-Ras-G12D knock-in alleles that can be activated by Cre in lung club cells. Mutation of the p53 transactivation domain (TAD) (p53-L25Q/W26S/R172H) eliminating significant transactivation activity resulted in loss of tumorigenicity, demonstrating that transactivation mediated by or dependent on TAD is required for oncogenicity by GOF p53. GOF p53 TAD mutations significantly reduce phosphorylation of nearby p53 serine 20 (S20), which is a target for PLK3 phosphorylation. Knocking out PLK3 attenuated S20 phosphorylation along with transactivation and oncogenicity by GOF p53, indicating that GOF p53 exploits PLK3 to trigger its transactivation capability and exert oncogenic functions. Our data show a mechanistic involvement of PLK3 in mutant p53 pathway of oncogenesis.


Assuntos
Carcinogênese/genética , Neoplasias Pulmonares/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteína Supressora de Tumor p53/genética , Animais , Carcinogênese/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Mutação com Ganho de Função , Técnicas de Introdução de Genes , Técnicas de Inativação de Genes , Humanos , Pulmão/patologia , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Transgênicos , Fosforilação/genética , Domínios Proteicos/genética , Proteínas Serina-Treonina Quinases/genética , Serina/metabolismo , Esferoides Celulares , Ativação Transcricional , Proteína Supressora de Tumor p53/metabolismo
3.
Int J Mol Sci ; 22(2)2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33440850

RESUMO

Neurodegenerative disorders can induce modifications of several proteins; one of which is ceruloplasmin (Cp), a ferroxidase enzyme found modified in the cerebrospinal fluid (CSF) of neurodegenerative diseases patients. Cp modifications are caused by the oxidation induced by the pathological environment and are usually associated with activity loss. Together with oxidation, deamidation of Cp was found in the CSF from Alzheimer's and Parkinson's disease patients. Protein deamidation is a process characterized by asparagine residues conversion in either aspartate or isoaspartate, depending on protein sequence/structure and cellular environment. Cp deamidation occurs at two Asparagine-Glycine-Arginine (NGR)-motifs which, once deamidated to isoAspartate-Glycine-Arginine (isoDGR), bind integrins, a family of receptors mediating cell adhesion. Therefore, on the one hand, Cp modifications lead to loss of enzymatic activity, while on the other hand, these alterations confer gain of function to Cp. In fact, deamidated Cp binds to integrins and triggers intracellular signaling on choroid plexus epithelial cells, changing cell functioning. Working in concert with the oxidative environment, Cp deamidation could reach different target cells in the brain, altering their physiology and causing detrimental effects, which might contribute to the pathological mechanism.


Assuntos
Ceruloplasmina/genética , Ceruloplasmina/metabolismo , Suscetibilidade a Doenças , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/metabolismo , Neurônios/metabolismo , Motivos de Aminoácidos , Aminoácidos/metabolismo , Animais , Encéfalo/metabolismo , Ceruloplasmina/química , Mutação com Ganho de Função , Predisposição Genética para Doença , Humanos , Integrinas/metabolismo , Mutação com Perda de Função , Oligopeptídeos/química
6.
BMC Infect Dis ; 21(1): 38, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33413180

RESUMO

BACKGROUND: Chronic mucocutaneous candidiasis (CMC) is the most common clinical symptom of singer transducer and signal transducer and activator of transcription 1 (STAT1) gain-of-function (GOF) mutations. Bronchiectasis is a chronic lung disease that is characterized by permanent bronchiectasis, causing cough, expectoration, and even haemoptysis. The underlying pathogeny is not yet clear. Immunoglobulin (Ig) A is derived from memory B cells and correlates with immune-related diseases. STAT1 is closely associated with signal transmission and immune regulation. CASE PRESENTATION: We report a 17-year-old male patient carrying a GOF mutation in STAT1. The variant led to CMC, bronchiectasis, and elevated serum IgA levels, as well as stunting. Whole-exome sequencing (WES) revealed a c.986C>G (p.P329R) heterozygous mutation in the STAT1 gene. CONCLUSION: Further Sanger sequencing analysis of STAT1 in the patient and his parents showed that the patient harboured a de novo mutation.


Assuntos
Bronquiectasia/genética , Candidíase Mucocutânea Crônica/genética , Transtornos do Crescimento/genética , Fator de Transcrição STAT1/genética , Adolescente , Linfócitos B/imunologia , Bronquiectasia/imunologia , Candidíase Mucocutânea Crônica/diagnóstico , Candidíase Mucocutânea Crônica/imunologia , Mutação com Ganho de Função , Heterozigoto , Humanos , Imunoglobulina A/sangue , Imunoglobulinas/sangue , Imunoglobulinas/genética , Masculino , Sequenciamento Completo do Exoma
7.
Life Sci ; 268: 118956, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33383047

RESUMO

AIMS: Breast cancer is one of the leading causes of woman deaths worldwide, being a major public health problem. It has been reported that the expression of the RNA-editing enzyme Adenosine Deaminase Acting on RNAs 1 (ADAR1) is upregulated in breast cancer, predicting poor prognosis in patients. A few reports in literature examine ADAR1 and long non-coding RNAs (lncRNAs) interplay in cancer and suggest key roles in cancer-related pathways. This study aimed to investigate whether ADAR1 could alter the expression levels of lncRNAs and explore how those changes are related to breast cancer biology. MAIN METHODS: ADAR1 overexpression and knockdown studies were performed in breast cancer cell lines to analyze the effects over lncRNAs expression. Guilt-by-Association correlation analysis of the TCGA-BRCA cohort was performed to predict the function of the lncRNA LINC00944. KEY FINDINGS: Here, we show that LINC00944 is responsive to ADAR1 up- and downregulation in breast cancer cells. We found that LINC00944 expression has a strong relationship with immune signaling pathways. Further assessment of the TCGA-BRCA cohort showed that LINC00944 expression was positively correlated to tumor-infiltrating T lymphocytes and pro-apoptotic markers. Moreover, we found that LINC00944 expression was correlated to the age at diagnosis, tumor size, and estrogen and progesterone receptor expression. Finally, we show that low expression of LINC00944 is correlated to poor prognosis in breast cancer patients. SIGNIFICANCE: Our study provides further evidence of the effect of ADAR1 over lncRNA expression levels, and on the participation of LINC00944 in breast cancer, suggesting to further investigate its potential role as prognostic biomarker.


Assuntos
Adenosina Desaminase/genética , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , RNA Longo não Codificante/genética , Proteínas de Ligação a RNA/genética , Adenosina Desaminase/metabolismo , Adulto , Apoptose/genética , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Mutação com Ganho de Função , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Estimativa de Kaplan-Meier , Linfócitos do Interstício Tumoral/patologia , Pessoa de Meia-Idade , Prognóstico , Proteínas de Ligação a RNA/metabolismo
8.
Cancer Sci ; 112(3): 1141-1149, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33377228

RESUMO

PIK3CA is the most frequently mutated oncogene in cervical cancer, and somatic mutations in the PIK3CA gene result in increased activity of PI3K. In cervical cancer, the E545K mutation in PIK3CA leads to elevated cell proliferation and reduced apoptosis. In the present study, we designed and synthesized a novel pyrrole-imidazole polyamide-seco-CBI conjugate, P3AE5K, to target the PIK3CA gene bearing the E545K mutation, rendered possible by nuclear access and the unique sequence specificity of pyrrole-imidazole polyamides. P3AE5K interacted with double-stranded DNA of the coding region containing the E545K mutation. When compared with conventional PI3K inhibitors, P3AE5K demonstrated strong cytotoxicity in E545K-positive cervical cancer cells at lower concentrations. PIK3CA mutant cells exposed to P3AE5K exhibited reduced expression levels of PIK3CA mRNA and protein, and subsequent apoptotic cell death. Moreover, P3AE5K significantly decreased the tumor growth in mouse xenograft models derived from PIK3CA mutant cells. Overall, the present data strongly suggest that the alkylating pyrrole-imidazole polyamide P3AE5K should be a promising new drug candidate targeting a constitutively activating mutation of PIK3CA in cervical cancer.


Assuntos
Antineoplásicos Alquilantes/farmacologia , Classe I de Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Neoplasias do Colo do Útero/tratamento farmacológico , Animais , Antineoplásicos Alquilantes/síntese química , Antineoplásicos Alquilantes/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Classe I de Fosfatidilinositol 3-Quinases/genética , Feminino , Mutação com Ganho de Função , Humanos , Imidazóis/síntese química , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Camundongos , Nylons/síntese química , Nylons/farmacologia , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/uso terapêutico , Pirróis/síntese química , Pirróis/farmacologia , Pirróis/uso terapêutico , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/patologia , Ensaios Antitumorais Modelo de Xenoenxerto
9.
PLoS One ; 15(12): e0243901, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33378376

RESUMO

Whereas recent clinical studies report metastatic melanoma survival rates high as 30-50%, many tumors remain nonresponsive or become resistant to current therapeutic strategies. Analyses of The Cancer Genome Atlas (TCGA) skin cutaneous melanoma (SKCM) data set suggests that a significant fraction of melanomas potentially harbor gain-of-function mutations in the gene that encodes for the ErbB4 receptor tyrosine kinase. In this work, a drug discovery strategy was developed that is based on the observation that the Q43L mutant of the naturally occurring ErbB4 agonist Neuregulin-2beta (NRG2ß) functions as a partial agonist at ErbB4. NRG2ß/Q43L stimulates tyrosine phosphorylation, fails to stimulate ErbB4-dependent cell proliferation, and inhibits agonist-induced ErbB4-dependent cell proliferation. Compounds that exhibit these characteristics likely function as ErbB4 partial agonists, and as such hold promise as therapies for ErbB4-dependent melanomas. Consequently, three highly sensitive and reproducible (Z' > 0.5) screening assays were developed and deployed for the identification of small-molecule ErbB4 partial agonists. Six compounds were identified that stimulate ErbB4 phosphorylation, fail to stimulate ErbB4-dependent cell proliferation, and appear to selectively inhibit ErbB4-dependent cell proliferation. Whereas further characterization is needed to evaluate the full therapeutic potential of these molecules, this drug discovery platform establishes reliable and scalable approaches for the discovery of ErbB4 inhibitors.


Assuntos
Proliferação de Células/genética , Melanoma/genética , Fatores de Crescimento Neural/genética , Receptor ErbB-4/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Descoberta de Drogas , Mutação com Ganho de Função/genética , Humanos , Melanoma/tratamento farmacológico , Melanoma/patologia , Fosforilação/genética , Receptor ErbB-4/agonistas , Receptor ErbB-4/antagonistas & inibidores , Transdução de Sinais/genética , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia
10.
PLoS One ; 15(12): e0243980, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33347465

RESUMO

Intellectual disability (ID) is a developmental disorder that includes both intellectual and adaptive functioning deficits in conceptual, social, and practical domains. Although evidence-based interventions for patients have long been desired, their progress has been hindered due to various determinants. One of these determinants is the complexity of the origins of ID. The ceramide transport protein (CERT) encoded by CERT1 mediates inter-organelle trafficking of ceramide for the synthesis of intracellular sphingomyelin. Utilizing whole exome sequencing analysis, we identified a novel CERT variant, which substitutes a serine at position 135 (S135) for a proline in a patient with severe ID. Biochemical analysis showed that S135 is essential for hyperphosphorylation of a serine-repeat motif of CERT, which is required for down-regulation of CERT activity. Amino acid replacements of S135 abnormally activated CERT and induced an intracellular punctate distribution pattern of this protein. These results identified specific ID-associated CERT1 mutations that induced gain-of-function effects on CERT activity. These findings provide a possible molecular basis for not only new diagnostics but also a conceivable pharmaceutical intervention for ID disorders caused by gain-of-function mutations in CERT1.


Assuntos
Mutação com Ganho de Função , Deficiência Intelectual/genética , Proteínas Serina-Treonina Quinases/genética , Células Cultivadas , Feminino , Células HCT116 , Humanos , Deficiência Intelectual/patologia , Domínios Proteicos , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Adulto Jovem
12.
J Pharmacol Sci ; 144(3): 139-146, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32921395

RESUMO

SHP2 is a non-receptor protein tyrosine phosphatase encoded by the PTPN11 gene in human. Clinically, SHP2 has been identified as a causal factor of several diseases, such as Noonan syndrome, LEOPARD syndrome as well as myeloid malignancies. Interestingly, both loss-of-function and gain-of-function mutations occur in the PTPN11 gene. Analyses by biochemical and cell biological means as well as probing with small molecule compounds have demonstrated that SHP2 has both phosphatase-dependent and independent functions. In comparison with its phosphatase activity, the non-phosphatase-like function of SHP2 has not been well introduced or summarized. This review mainly focuses on the phosphatase-independent functions and its regulation by small molecule compounds as well as their use for disease therapy.


Assuntos
Monoéster Fosfórico Hidrolases , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/fisiologia , Cerebrosídeos , Depsipeptídeos , Mutação com Ganho de Função , Humanos , Síndrome LEOPARD/genética , Mutação com Perda de Função , Terapia de Alvo Molecular , Síndrome de Noonan/genética , Monoéster Fosfórico Hidrolases/metabolismo , Piperidinas , Proteína Tirosina Fosfatase não Receptora Tipo 11/antagonistas & inibidores , Pirimidinas , Transdução de Sinais/genética
13.
Med Sci (Paris) ; 36(8-9): 783-796, 2020.
Artigo em Francês | MEDLINE | ID: mdl-32773024

RESUMO

SARS-CoV-2 is a new human coronavirus (CoV), which emerged in People's Republic of China at the end of 2019 and is responsible for the global Covid-19 pandemic that caused more than 540 000 deaths in six months. Understanding the origin of this virus is an important issue and it is necessary to determine the mechanisms of its dissemination in order to be able to contain new epidemics. Based on phylogenetic inferences, sequence analysis and structure-function relationships of coronavirus proteins, informed by the knowledge currently available, we discuss the different scenarios evoked to account for the origin - natural or synthetic - of the virus. On the basis of currently available data, it is impossible to determine whether SARS-CoV-2 is the result of a natural zoonotic emergence or an accidental escape from experimental strains. Regardless of its origin, the study of the evolution of the molecular mechanisms involved in the emergence of this pandemic virus is essential to develop therapeutic and vaccine strategies.


Assuntos
Betacoronavirus/genética , Doenças Transmissíveis Emergentes/virologia , Infecções por Coronavirus/virologia , Coronavirus/classificação , Evolução Molecular , Pandemias , Filogenia , Pneumonia Viral/virologia , RNA Viral/genética , Sequência de Aminoácidos , Animais , Betacoronavirus/classificação , Betacoronavirus/isolamento & purificação , Derramamento de Material Biológico , China/epidemiologia , Infecções por Coronaviridae/transmissão , Infecções por Coronaviridae/veterinária , Infecções por Coronaviridae/virologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/transmissão , Reservatórios de Doenças , Mutação com Ganho de Função , Genoma Viral , HIV/genética , Especificidade de Hospedeiro , Humanos , Mamíferos/virologia , Pneumonia Viral/epidemiologia , Pneumonia Viral/transmissão , Vírus Reordenados/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/fisiologia , Zoonoses
14.
PLoS Genet ; 16(8): e1008644, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776941

RESUMO

Correct regulation of cell contractility is critical for the function of many biological systems. The reproductive system of the hermaphroditic nematode C. elegans contains a contractile tube of myoepithelial cells known as the spermatheca, which stores sperm and is the site of oocyte fertilization. Regulated contraction of the spermatheca pushes the embryo into the uterus. Cell contractility in the spermatheca is dependent on actin and myosin and is regulated, in part, by Ca2+ signaling through the phospholipase PLC-1, which mediates Ca2+ release from the endoplasmic reticulum. Here, we describe a novel role for GSA-1/Gαs, and protein kinase A, composed of the catalytic subunit KIN-1/PKA-C and the regulatory subunit KIN-2/PKA-R, in the regulation of Ca2+ release and contractility in the C. elegans spermatheca. Without GSA-1/Gαs or KIN-1/PKA-C, Ca2+ is not released, and oocytes become trapped in the spermatheca. Conversely, when PKA is activated through either a gain of function allele in GSA-1 (GSA-1(GF)) or by depletion of KIN-2/PKA-R, the transit times and total numbers, although not frequencies, of Ca2+ pulses are increased, and Ca2+ propagates across the spermatheca even in the absence of oocyte entry. In the spermathecal-uterine valve, loss of GSA-1/Gαs or KIN-1/PKA-C results in sustained, high levels of Ca2+ and a loss of coordination between the spermathecal bag and sp-ut valve. Additionally, we show that depleting phosphodiesterase PDE-6 levels alters contractility and Ca2+ dynamics in the spermatheca, and that the GPB-1 and GPB-2 Gß subunits play a central role in regulating spermathecal contractility and Ca2+ signaling. This work identifies a signaling network in which Ca2+ and cAMP pathways work together to coordinate spermathecal contractions for successful ovulations.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Sinalização do Cálcio , Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico/metabolismo , Contração Muscular , 3',5'-AMP Cíclico Fosfodiesterases/metabolismo , Animais , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico/genética , Células Epiteliais/metabolismo , Células Epiteliais/fisiologia , Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Mutação com Ganho de Função , Células Musculares/metabolismo , Células Musculares/fisiologia , Oócitos/fisiologia
15.
PLoS One ; 15(8): e0237101, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817686

RESUMO

Mutations in the genes encoding for voltage-gated sodium channels cause profound sensory disturbances and other symptoms dependent on the distribution of a particular channel subtype in different organs. Humans with the gain-of-function mutation p.Leu811Pro in SCN11A (encoding for the voltage-gated Nav1.9 channel) exhibit congenital insensitivity to pain, pruritus, self-inflicted injuries, slow healing wounds, muscle weakness, Charcot-like arthropathies, and intestinal dysmotility. As already shown, knock-in mice (Scn11a+/L799P) carrying the orthologous mutation p.Leu799Pro replicate reduced pain sensitivity and show frequent tissue lesions. In the present study we explored whether Scn11a+/L799P mice develop also pruritus, muscle weakness, and changes in gastrointestinal transit time. Furthermore, we analyzed morphological and functional differences in nerves, skeletal muscle, joints and small intestine from Scn11a+/L799P and Scn11a+/+ wild type mice. Compared to Scn11a+/+ mice, Scn11a+/L799P mice showed enhanced scratching bouts before skin lesions developed, indicating pruritus. Scn11a+/L799P mice exhibited reduced grip strength, but no disturbances in motor coordination. Skeletal muscle fiber types and joint architecture were unaltered in Scn11a+/L799P mice. Their gastrointestinal transit time was unaltered. The small intestine from Scn11a+/L799P showed a small shift towards less frequent peristaltic movements. Similar proportions of lumbar dorsal root ganglion neurons from Scn11a+/L799P and Scn11a+/+ mice were calcitonin gene-related peptide (CGRP-) positive, but isolated sciatic nerves from Scn11a+/L799P mice exhibited a significant reduction of the capsaicin-evoked release of CGRP indicating reduced neurogenic inflammation. These data indicate important Nav1.9 channel functions in several organs in both humans and mice. They support the pathophysiological relevance of increased basal activity of Nav1.9 channels for sensory abnormalities (pain and itch) and suggest resulting malfunctions of the motor system and of the gastrointestinal tract. Scn11a+/L799P mice are suitable to investigate the role of Nav1.9, and to explore the pathophysiological changes and mechanisms which develop as a consequence of Nav1.9 hyperactivity.


Assuntos
Mutação com Ganho de Função , Debilidade Muscular/genética , Canal de Sódio Disparado por Voltagem NAV1.9/genética , Prurido/genética , Animais , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Feminino , Trânsito Gastrointestinal , Força da Mão , Intestino Delgado/metabolismo , Intestino Delgado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Movimento , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Canal de Sódio Disparado por Voltagem NAV1.9/metabolismo , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia
16.
Bioessays ; 42(10): e2000091, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32786014

RESUMO

Despite claims from prominent scientists that SARS-CoV-2 indubitably emerged naturally, the etiology of this novel coronavirus remains a pressing and open question: Without knowing the true nature of a disease, it is impossible for clinicians to appropriately shape their care, for policy-makers to correctly gauge the nature and extent of the threat, and for the public to appropriately modify their behavior. Unless the intermediate host necessary for completing a natural zoonotic jump is identified, the dual-use gain-of-function research practice of viral serial passage should be considered a viable route by which the novel coronavirus arose. The practice of serial passage mimics a natural zoonotic jump, and offers explanations for SARS-CoV-2's distinctive spike-protein region and its unexpectedly high affinity for angiotensin converting enzyme (ACE2), as well as the notable polybasic furin cleavage site within it. Additional molecular clues raise further questions, all of which warrant full investigation into the novel coronavirus's origins and a re-examination of the risks and rewards of dual-use gain-of-function research.


Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/etiologia , Infecções por Coronavirus/transmissão , Pneumonia Viral/etiologia , Pneumonia Viral/transmissão , Zoonoses/transmissão , Sequência de Aminoácidos , Animais , Betacoronavirus/crescimento & desenvolvimento , Mutação com Ganho de Função/genética , Humanos , Pandemias , Peptidil Dipeptidase A/metabolismo , Ligação Proteica , Inoculações Seriadas , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Zoonoses/virologia
17.
mBio ; 11(4)2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32769091

RESUMO

Proponents of the use of gain-of-function (GOF) experiments with pathogens with pandemic potential (PPP) have argued that such experiments are necessary because they reveal important facets of pathogenesis and can be performed safely. Opponents of GOF experiments with PPP have argued that the risks outweigh the knowledge gained. The COVID-19 pandemic demonstrates the vulnerability of human societies to a new PPP, while also validating some arguments of both camps, questioning others, and suggesting the need to rethink how we approach this class of experiments.


Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/virologia , Mutação com Ganho de Função , Pneumonia Viral/virologia , Pesquisa Biomédica/ética , Pesquisa Biomédica/normas , Bioterrorismo , Contenção de Riscos Biológicos/ética , Contenção de Riscos Biológicos/normas , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Humanos , Virus da Influenza A Subtipo H5N1/genética , Influenza Humana/epidemiologia , Influenza Humana/virologia , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle
18.
PLoS Genet ; 16(8): e1008975, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32750056

RESUMO

The C. elegans proteins PAQR-2 (a homolog of the human seven-transmembrane domain AdipoR1 and AdipoR2 proteins) and IGLR-2 (a homolog of the mammalian LRIG proteins characterized by a single transmembrane domain and the presence of immunoglobulin domains and leucine-rich repeats in their extracellular portion) form a complex that protects against plasma membrane rigidification by promoting the expression of fatty acid desaturases and the incorporation of polyunsaturated fatty acids into phospholipids, hence increasing membrane fluidity. In the present study, we leveraged a novel gain-of-function allele of PAQR-1, a PAQR-2 paralog, to carry out structure-function studies. We found that the transmembrane domains of PAQR-2 are responsible for its functional requirement for IGLR-2, that PAQR-1 does not require IGLR-2 but acts via the same pathway as PAQR-2, and that the divergent N-terminal cytoplasmic domains of the PAQR-1 and PAQR-2 proteins serve a regulatory function and may regulate access to the catalytic site of these proteins. We also show that overexpression of human AdipoR1 or AdipoR2 alone is sufficient to confer increased palmitic acid resistance in HEK293 cells, and thus act in a manner analogous to the PAQR-1 gain-of-function allele.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Proteínas de Membrana/genética , Receptores de Adiponectina/genética , Alelos , Animais , Caenorhabditis elegans/metabolismo , Membrana Celular/genética , Membrana Celular/metabolismo , Mutação com Ganho de Função/genética , Células HEK293 , Humanos , Fluidez de Membrana/genética , Fenótipo , Fosfolipídeos/genética , Fosfolipídeos/metabolismo
19.
Am J Hum Genet ; 107(2): 311-324, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32738225

RESUMO

Aminoacyl-tRNA synthetases (ARSs) are ubiquitous, ancient enzymes that charge amino acids to cognate tRNA molecules, the essential first step of protein translation. Here, we describe 32 individuals from 21 families, presenting with microcephaly, neurodevelopmental delay, seizures, peripheral neuropathy, and ataxia, with de novo heterozygous and bi-allelic mutations in asparaginyl-tRNA synthetase (NARS1). We demonstrate a reduction in NARS1 mRNA expression as well as in NARS1 enzyme levels and activity in both individual fibroblasts and induced neural progenitor cells (iNPCs). Molecular modeling of the recessive c.1633C>T (p.Arg545Cys) variant shows weaker spatial positioning and tRNA selectivity. We conclude that de novo and bi-allelic mutations in NARS1 are a significant cause of neurodevelopmental disease, where the mechanism for de novo variants could be toxic gain-of-function and for recessive variants, partial loss-of-function.


Assuntos
Aspartato-tRNA Ligase/genética , Mutação com Ganho de Função/genética , Mutação com Perda de Função/genética , Transtornos do Neurodesenvolvimento/genética , Aminoacil-RNA de Transferência/genética , Alelos , Aminoacil-tRNA Sintetases/genética , Linhagem Celular , Feminino , Predisposição Genética para Doença/genética , Humanos , Masculino , Linhagem , RNA de Transferência/genética , Células-Tronco/fisiologia
20.
Science ; 369(6499): 59-64, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32631887

RESUMO

Eukaryotic histone H3-H4 tetramers contain a putative copper (Cu2+) binding site at the H3-H3' dimerization interface with unknown function. The coincident emergence of eukaryotes with global oxygenation, which challenged cellular copper utilization, raised the possibility that histones may function in cellular copper homeostasis. We report that the recombinant Xenopus laevis H3-H4 tetramer is an oxidoreductase enzyme that binds Cu2+ and catalyzes its reduction to Cu1+ in vitro. Loss- and gain-of-function mutations of the putative active site residues correspondingly altered copper binding and the enzymatic activity, as well as intracellular Cu1+ abundance and copper-dependent mitochondrial respiration and Sod1 function in the yeast Saccharomyces cerevisiae The histone H3-H4 tetramer, therefore, has a role other than chromatin compaction or epigenetic regulation and generates biousable Cu1+ ions in eukaryotes.


Assuntos
Cobre/metabolismo , Histonas/química , Oxirredutases/química , Multimerização Proteica , Animais , Biocatálise , Domínio Catalítico/genética , Mutação com Ganho de Função , Histonas/genética , Histonas/metabolismo , Mitocôndrias/metabolismo , Proteínas Nucleares/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Superóxido Dismutase-1/química , Fatores de Transcrição/metabolismo , Xenopus laevis
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