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1.
An Acad Bras Cienc ; 93(suppl 1): e20200880, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33624727

RESUMO

The almost universal availability of electronic connectivity, portable devices, and the web is bringing about a major revolution: information of all kinds is rapidly becoming accessible to everyone, transforming social, economic and cultural life practically everywhere in the world. Internet technologies represent an unprecedented and extraordinary two-way channel of communication between producers and users of data. "Open Universe" is an initiative proposed to the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) and currently in implementation under the leadership of the United Nations Office for Outer Space Affairs (UN-OOSA). Its primary objective is to stimulate a dramatic increase in the availability and usability of space science data, extending the potential of scientific discovery to new participants in all parts of the world. This paper describes the initiative in general, some of the activities carried out to demonstrate its feasibility, and its use in the context of the BRICS Astronomy Programme.


Assuntos
Astronomia , Nações Unidas , Humanos , Tecnologia
2.
Scand J Clin Lab Invest ; 80(6): 508-514, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32706999

RESUMO

Familial hypercholesterolemia (FH) is a monogenic disease characterized by a lifelong exposure to high LDL-C levels that can lead to early onset coronary heart disease (CHD). The main causes of FH identified to date include loss-of-function mutations in LDLR or APOB, or gain-of-function mutations in PCSK9. Early diagnosis and genetic testing of FH suspects is critical for improved prognosis of affected individuals as lipid lowering treatments are effective in preventing CHD related morbidity and mortality. In the present study, we carried out a comprehensive screening, using a next-generation sequencing (NGS) panel, for FH culprit mutations in two Icelandic studies representative of either FH families or the general population. We confirmed all previously known mutations in the FH families, and identified two subjects that had been misdiagnosed clinically at young age. We identified six new mutations in the Icelandic FH families and detected three pathogenic mutations in the general population-based study. The application of the NGS panel revealed substantial diagnostic yields in identifying pathogenic mutations, or 68.2% of those with definite clinical diagnosis of FH in the family material and 5.6-fold enrichment in the population-based genetic testing.


Assuntos
Testes Genéticos/métodos , Hiperlipoproteinemia Tipo II/diagnóstico , Predisposição Genética para Doença , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Hiperlipoproteinemia Tipo II/genética , Islândia , Mutação com Perda de Função , Mutação , Estudos Prospectivos
3.
PLoS Comput Biol ; 16(3): e1007687, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32218567

RESUMO

Tuberculosis (TB) remains a public health threat in low TB incidence countries, through a combination of reactivated disease and onward transmission. Using surveillance data from the United Kingdom (UK) and the Netherlands (NL), we demonstrate a simple and predictable relationship between the probability of observing a cluster and its size (the number of cases with a single genotype). We demonstrate that the full range of observed cluster sizes can be described using a modified branching process model with the individual reproduction number following a Poisson lognormal distribution. We estimate that, on average, between 2010 and 2015, a TB case generated 0.41 (95% CrI 0.30,0.60) secondary cases in the UK, and 0.24 (0.14,0.48) secondary cases in the NL. A majority of cases did not generate any secondary cases. Recent transmission accounted for 39% (26%,60%) of UK cases and 23%(13%,37%) of NL cases. We predict that reducing UK transmission rates to those observed in the NL would result in 538(266,818) fewer cases annually in the UK. In conclusion, while TB in low incidence countries is strongly associated with reactivated infections, we demonstrate that recent transmission remains sufficient to warrant policies aimed at limiting local TB spread.


Assuntos
Modelos Biológicos , Tuberculose , Biologia Computacional , Epidemiologia , Humanos , Incidência , Mycobacterium tuberculosis/genética , Países Baixos/epidemiologia , Tuberculose/epidemiologia , Tuberculose/transmissão , Reino Unido/epidemiologia
4.
J Assist Reprod Genet ; 37(2): 341-346, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31792669

RESUMO

PURPOSE: To study the incidence of tumor suppressor gene (TSG) mutations in men and women with impaired gametogenesis. METHODS: Gene association analyses were performed on blood samples in two distinct patient populations: males with idiopathic male infertility and females with unexplained diminished ovarian reserve (DOR). The male study group consisted of men with idiopathic azoospermia, oligozoospermia, asthenozoospermia, or teratozoospermia. Age-matched controls were men with normal semen analyses. The female study group consisted of women with unexplained DOR with anti-Müllerian hormone levels ≤ 1.1 ng/mL. Controls were age-matched women with normal ovarian reserve (> 1.1 ng/mL). RESULTS: Fifty-seven male cases (mean age = 38.4; mean sperm count = 15.7 ± 12.1; mean motility = 38.2 ± 24.7) and 37 age-matched controls (mean age = 38.0; mean sperm count = 89.6 ± 37.5; mean motility = 56.2 ± 14.3) were compared. Variants observed in CHD5 were found to be enriched in the study group (p = 0.000107). The incidence of CHD5 mutation c.*3198_*3199insT in the 3'UTR (rs538186680) was significantly higher in cases compared to controls (p = 0.0255). 72 DOR cases (mean age = 38.7; mean AMH = 0.5 ± 0.3; mean FSH = 11.7 ± 12.5) and 48 age-matched controls (mean age = 37.6; mean AMH = 4.1 ± 3.0; mean FSH = 7.1 ± 2.2) were compared. Mutations in CHD5 (c.-140A>C), RB1 (c.1422-18delT, rs70651121), and TP53 (c.376-161A>G, rs75821853) were found at significantly higher frequencies in DOR cases compared to controls (p ≤ 0.05). In addition, 363 variants detected in the DOR patients were not present in the control group. CONCLUSION: Unexplained impaired gametogenesis in both males and females may be associated with genetic variation in TSGs. TSGs, which play cardinal roles in cell-cycle control, might also be critical for normal spermatogenesis and oogenesis. If validated in larger prospective studies, it is possible that TSGs provide an etiological basis for some patients with impaired gametogenesis.


Assuntos
Infertilidade Feminina/genética , Infertilidade Masculina/genética , Reserva Ovariana/genética , Espermatogênese/genética , Adulto , DNA Helicases/genética , Feminino , Gametogênese/genética , Genes Supressores de Tumor , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Infertilidade Feminina/patologia , Infertilidade Masculina/patologia , Masculino , Mutação/genética , Proteínas do Tecido Nervoso/genética , Proteínas de Ligação a Retinoblastoma/genética , Contagem de Espermatozoides , Motilidade dos Espermatozoides/genética , Espermatozoides/patologia , Proteína Supressora de Tumor p53/genética , Ubiquitina-Proteína Ligases/genética
5.
Mol Neurobiol ; 56(11): 7508-7521, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31044367

RESUMO

Proper appetite, energy expenditure, and glucose and fat metabolisms are regulated by neurons in the arcuate nucleus (ARC) of mammalian hypothalamus. Studies have shown sex-specific difference in diet-induced obesity, but the underlying mechanisms remain unclear. Here, we show that microRNA (miRNA) miR-7 and miR-17-92 are expressed in proopiomelanocortin (POMC)-expressing neurons in the mouse ARC. Specific knockdown of miR-7 and knockout of miR-17-92 in POMC-expressing neurons aggravate diet-induced obesity only in females and males, respectively. Sex-differentially expressed genes are identified in the male and female ARC of wild-type adult mice using RNA sequencing. Interestingly, some target genes for miR-7 and miR-17-92 not only display sex-differential expression in the male and female ARC but also respond to high-fat diet treatment in miR-7 knockdown and miR-17-92 knockout mice. Our results demonstrate an important role of miRNAs in regulating sex-specific diet-induced obesity, likely through modulating expression of target genes that show sex-differential expression in the ARC of the hypothalamus.


Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , MicroRNAs/metabolismo , Obesidade/genética , Caracteres Sexuais , Animais , Peso Corporal , Dieta Hiperlipídica , Feminino , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Glucose/metabolismo , Masculino , Camundongos , MicroRNAs/genética , Neurônios/metabolismo , Pró-Opiomelanocortina/metabolismo
6.
Psychiatr Psychol Law ; 26(1): 110-128, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31984068

RESUMO

This study aims to identify whether a model of juror decision-making (i.e. the threshold point model) that encompasses both rational and intuitive decision-making exists. A total of 60 participants were selected who are eligible for jury duty in Scotland. These individuals read nine vignettes and rated the evidence of each vignette separately by placing the evidence in either a guilty, a not guilty or a not proven (a verdict type specific to Scotland) counter. Participants were asked after being presented with each piece of information to state how likely they thought the suspect was of being guilty, on a scale from 1 to 100. The data are best described using a flexible model (i.e. a diffusion model) that allows for information integration. Future research should examine whether or not the diffusion model can explain cognitive fallacies, such as confirmation bias, that are commonly studied in decision science.

7.
Front Cell Neurosci ; 12: 259, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30210296

RESUMO

Brain morphogenesis requires precise regulation of multiple genes to control specification of distinct neural progenitors (NPs) and neuronal production. Dysregulation of these genes results in severe brain malformation such as macrocephaly and microcephaly. Despite studies of the effect of individual pathogenic genes, the counter-balance between multiple factors in controlling brain size remains unclear. Here we show that cortical deletion of Gli3 results in enlarged brain and folding structures in the cortical midline at the postnatal stage, which is mainly caused by the increased percentage of intermediate progenitors (IPs) and newborn neurons. In addition, dysregulation of neuronal migration also contributes to the folding defects in the cortical midline region. Knockdown of microRNA (miRNA) miR-7 can rescue abnormal brain morphology in Gli3 knockout mice by recovering progenitor specification, neuronal production and migration through a counter-balance of the Gli3 activity. Moreover, miR-7 likely exerts its function through silencing target gene Pax6. Our results indicate that proper brain morphogenesis is an outcome of interactive regulations of multiple molecules such as Gli3 and miR-7. Because miRNAs are easy to synthesize and deliver, miR-7 could be a potential therapeutic means to macrocephaly caused by Gli3-deficiency.

8.
J Assist Reprod Genet ; 35(8): 1489-1496, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29779145

RESUMO

PURPOSE: To develop a comprehensive genetic test for female and male infertility in support of medical decisions during assisted reproductive technology (ART) protocols. METHODS: We developed a next-generation sequencing (NGS) gene panel consisting of 87 genes including promoters, 5' and 3' untranslated regions, exons, and selected introns. In addition, sex chromosome aneuploidies and Y chromosome microdeletions were analyzed concomitantly using the same panel. RESULTS: The NGS panel was analytically validated by retrospective analysis of 118 genomic DNA samples with known variants in loci representative of female and male infertility. Our results showed analytical accuracy of > 99%, with > 98% sensitivity for single-nucleotide variants (SNVs) and > 91% sensitivity for insertions/deletions (indels). Clinical sensitivity was assessed with samples containing variants representative of male and female infertility, and it was 100% for SNVs/indels, CFTR IVS8-5T variants, sex chromosome aneuploidies, and copy number variants (CNVs) and > 93% for Y chromosome microdeletions. Cost analysis shows potential savings when comparing this single NGS assay with the standard approach, which includes multiple assays. CONCLUSIONS: A single, comprehensive, NGS panel can simplify the ordering process for healthcare providers, reduce turnaround time, and lower the overall cost of testing for genetic assessment of infertility in females and males, while maintaining accuracy.


Assuntos
Testes Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Infertilidade Feminina/genética , Infertilidade Masculina/genética , Variações do Número de Cópias de DNA/genética , Éxons , Feminino , Humanos , Mutação INDEL/genética , Infertilidade Feminina/diagnóstico , Infertilidade Feminina/patologia , Infertilidade Masculina/diagnóstico , Infertilidade Masculina/patologia , Masculino , Polimorfismo de Nucleotídeo Único/genética
9.
Proc Natl Acad Sci U S A ; 112(52): 16006-11, 2015 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-26668376

RESUMO

Molecular chaperone Heat Shock Protein 70 (Hsp70) plays an important protective role in various neurodegenerative disorders often associated with aging, but its activity and availability in neuronal tissue decrease with age. Here we explored the effects of intranasal administration of exogenous recombinant human Hsp70 (eHsp70) on lifespan and neurological parameters in middle-aged and old mice. Long-term administration of eHsp70 significantly enhanced the lifespan of animals of different age groups. Behavioral assessment after 5 and 9 mo of chronic eHsp70 administration demonstrated improved learning and memory in old mice. Likewise, the investigation of locomotor and exploratory activities after eHsp70 treatment demonstrated a significant therapeutic effect of this chaperone. Measurements of synaptophysin show that eHsp70 treatment in old mice resulted in larger synaptophysin-immunopositive areas and higher neuron density compared with control animals. Furthermore, eHsp70 treatment decreased accumulation of lipofuscin, an aging-related marker, in the brain and enhanced proteasome activity. The potential of eHsp70 intranasal treatment to protect synaptic machinery in old animals offers a unique pharmacological approach for various neurodegenerative disorders associated with human aging.


Assuntos
Envelhecimento/efeitos dos fármacos , Cognição/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/farmacologia , Proteínas Recombinantes/farmacologia , Animais , Western Blotting , Encéfalo/citologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Comportamento Exploratório/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/genética , Humanos , Lipofuscina/metabolismo , Longevidade/efeitos dos fármacos , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Memória/efeitos dos fármacos , Camundongos Endogâmicos , Microscopia de Fluorescência , Atividade Motora/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Subunidades Proteicas/metabolismo , Sinaptofisina/metabolismo
10.
Cell Rep ; 7(4): 1184-96, 2014 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-24813889

RESUMO

Proper growth of the mammalian cerebral cortex is crucial for normal brain functions and is controlled by precise gene-expression regulation. Here, we show that microRNA-7 (miR-7) is highly expressed in cortical neural progenitors and describe miR-7 sponge transgenic mice in which miR-7-silencing activity is specifically knocked down in the embryonic cortex. Blocking miR-7 function causes microcephaly-like brain defects due to reduced intermediate progenitor (IP) production and apoptosis. Upregulation of miR-7 target genes, including those implicated in the p53 pathway, such as Ak1 and Cdkn1a (p21), is responsible for abnormalities in neural progenitors. Furthermore, ectopic expression of Ak1 or p21 and specific blockade of miR-7 binding sites in target genes using protectors in vivo induce similarly reduced IP production. Using conditional miRNA sponge transgenic approaches, we uncovered an unexpected role for miR-7 in cortical growth through its interactions with genes in the p53 pathway.


Assuntos
Córtex Cerebral/crescimento & desenvolvimento , Regulação da Expressão Gênica , MicroRNAs/genética , Proteína Supressora de Tumor p53/genética , Animais , Linhagem Celular Tumoral , Córtex Cerebral/metabolismo , Córtex Cerebral/fisiologia , Camundongos , Camundongos Transgênicos , MicroRNAs/metabolismo , Proteína Supressora de Tumor p53/metabolismo
11.
Proc Natl Acad Sci U S A ; 110(17): 7056-61, 2013 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-23569256

RESUMO

Cerebral cortical neurons arise from radial glia (direct neurogenesis) or from intermediate progenitors (indirect neurogenesis); intriguingly, the sizes of intermediate progenitor populations and the cortices they generate correlate across species. The generation of intermediate progenitors is regulated by the transcription factor Tbr2, whose expression marks these cells. We investigated how this mechanism might be controlled. We found that acute blockade of mature microRNA biosynthesis in murine cortical progenitors caused a rapid cell autonomous increase in numbers of Tbr2-expressing cells. Acute microRNA-92b (miR-92b) gain of function caused rapid reductions in numbers of Tbr2-expressing cells and proliferating intermediate progenitors. Acute miR-92b loss of function had opposite effects. These findings indicate that miR-92b limits the production of intermediate cortical progenitors.


Assuntos
Córtex Cerebral/citologia , MicroRNAs/metabolismo , Células-Tronco Neurais/fisiologia , Neurogênese/fisiologia , Neurônios/citologia , Animais , Bromodesoxiuridina , Imuno-Histoquímica , Hibridização In Situ , Luciferases , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Neurogênese/genética , Reação em Cadeia da Polimerase em Tempo Real , Proteínas com Domínio T/metabolismo
12.
Cell Rep ; 3(5): 1398-1406, 2013 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-23623502

RESUMO

During development of the embryonic neocortex, tightly regulated expansion of neural stem cells (NSCs) and their transition to intermediate progenitors (IPs) are critical for normal cortical formation and function. Molecular mechanisms that regulate NSC expansion and transition remain unclear. Here, we demonstrate that the microRNA (miRNA) miR-17-92 cluster is required for maintaining proper populations of cortical radial glial cells (RGCs) and IPs through repression of Pten and Tbr2 protein. Knockout of miR-17-92 and its paralogs specifically in the developing neocortex restricts NSC proliferation, suppresses RGC expansion, and promotes transition of RGCs to IPs. Moreover, Pten and Tbr2 protectors specifically block silencing activities of endogenous miR-17-92 and control proper numbers of RGCs and IPs in vivo. Our results demonstrate a critical role for miRNAs in promoting NSC proliferation and modulating the cell-fate decision of generating distinct neural progenitors in the developing neocortex.


Assuntos
MicroRNAs/metabolismo , Neocórtex/metabolismo , Células-Tronco Neurais/citologia , Regiões 3' não Traduzidas , Animais , Sequência de Bases , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Desenvolvimento Embrionário , Camundongos , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Mutação , Neocórtex/citologia , Células-Tronco Neurais/metabolismo , Neuroglia/citologia , PTEN Fosfo-Hidrolase/química , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Proteínas com Domínio T/química , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo
13.
Mol Neurobiol ; 45(3): 586-95, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22614130

RESUMO

Cell fate reprogramming makes possible the generation of new cell types from healthy adult cells to replace those lost or damaged in disease. Additionally, reprogramming patient cells into specific cell types allows for drug screening and the development of new therapeutic tools. Generation of new neurons is of particular interest because of the potential to treat diseases of the nervous system, such as neurodegenerative disorders and spinal cord injuries, with cell replacement therapy. Recent advances in cell fate reprogramming have led to the development of novel methods for the direct conversion of fibroblasts into neurons and neural stem cells. This review will highlight the advantages of these new methods over neuronal induction from embryonic stem cells and induced pluripotent stem cells, as well as outline the limitations and the potential for future applications.


Assuntos
Encéfalo/citologia , Fibroblastos/citologia , Neurônios/citologia , Pele/citologia , Animais , Fibroblastos/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Neurogênese , Neurônios/metabolismo
14.
J Neurosci ; 31(3): 809-18, 2011 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-21248104

RESUMO

The precise organization of motor neuron subtypes in a columnar pattern in developing spinal cords is controlled by cross-interactions of multiple transcription factors and segmental expressions of Hox genes and their accessory proteins. Accurate expression levels and domains of these regulators are essential for organizing spinal motor neuron columns and axonal projections to target muscles. Here, we show that microRNA miR-9 is transiently expressed in a motor neuron subtype and displays overlapping expression with its target gene FoxP1. Overexpression or knockdown of miR-9 alters motor neuron subtypes, switches columnar identities, and changes axonal innervations in developing chick spinal cords. miR-9 modifies spinal columnar organization by specifically regulating FoxP1 protein levels, which in turn determine distinct motor neuron subtypes. Our findings demonstrate that miR-9 is an essential regulator of motor neuron specification and columnar formation. Moreover, the overlapping expression of miR-9 and its target FoxP1 further illuminates the importance of fine-tuning regulation by microRNAs in motor neuron development.


Assuntos
Fatores de Transcrição Forkhead/metabolismo , MicroRNAs/metabolismo , Neurônios Motores/metabolismo , Proteínas Repressoras/metabolismo , Medula Espinal/embriologia , Análise de Variância , Animais , Western Blotting , Embrião de Galinha , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica no Desenvolvimento , Imuno-Histoquímica , Hibridização In Situ , MicroRNAs/genética , Proteínas Repressoras/genética , Medula Espinal/metabolismo
15.
Nat Genet ; 43(1): 79-84, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21131974

RESUMO

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous autosomal recessive disorder characterized by recurrent infections of the respiratory tract associated with the abnormal function of motile cilia. Approximately half of individuals with PCD also have alterations in the left-right organization of their internal organ positioning, including situs inversus and situs ambiguous (Kartagener's syndrome). Here, we identify an uncharacterized coiled-coil domain containing a protein, CCDC40, essential for correct left-right patterning in mouse, zebrafish and human. In mouse and zebrafish, Ccdc40 is expressed in tissues that contain motile cilia, and mutations in Ccdc40 result in cilia with reduced ranges of motility. We further show that CCDC40 mutations in humans result in a variant of PCD characterized by misplacement of the central pair of microtubules and defective assembly of inner dynein arms and dynein regulatory complexes. CCDC40 localizes to motile cilia and the apical cytoplasm and is required for axonemal recruitment of CCDC39, disruption of which underlies a similar variant of PCD.


Assuntos
Transtornos da Motilidade Ciliar/genética , Proteínas/genética , Animais , Cílios/genética , Dineínas/genética , Humanos , Síndrome de Kartagener/genética , Camundongos , Camundongos Endogâmicos , Mutação , Proteínas/fisiologia , Situs Inversus/genética , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
16.
Front Neurosci ; 5: 146, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22291613

RESUMO

The specification of motor neuron (MN) subtypes and columnar organization in developing spinal cord is controlled by multiple transcription factors. FoxP1 drives specification of lateral motor neuron (LMN) subtypes, and we demonstrated in our previous work that FoxP1 expression levels are regulated by the microRNA miR-9. Here we show that ectopic FoxP1 expression in the chick spinal cord can rescue Lhx3 and Hb9 expression in MNs altered by miR-9 over-expression, demonstrating that FoxP1 is a critical functional interaction partner for miR-9 in LMN development. Moreover, we have optimized a technique called a miRNA sponge in vitro, to permit easy discovery of the role of individual miRNA in vivo using a loss-of-function approach. We here show that narrow spacing between binding sites, inclusion of a coding gene, and optimizing the number of miRNA binding sites can significantly increase the blocking ability of a sponge. We go on to show that a miR-9 sponge reduces detectable miR-9 in the ventral horn, preventing miR-9 silencing of FoxP1 in vivo, and in turn modifies MN subtypes in the spinal cord. Our designs for optimized sponges provide a knockdown tool that is ready to be used to study the function of miRNA in vivo, and in particular for generating transgenic animal models.

17.
J Cell Sci ; 123(Pt 4): 586-94, 2010 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-20103535

RESUMO

An important function of the RNAase-III enzyme Dicer is to process microRNA precursors into ~22-nucleotide non-coding small RNAs. But little is known about the role of Dicer in mammalian brain formation and neural stem cell (NSC) development. Here we show that Dicer plays a crucial role in controlling mouse cortical NSC development. We found that Dicer function is essential for expanding cortical neural progenitors and NSCs. We have identified a population of Dicer-deficient NSCs that can self-renew, and that display normal karyotype and heterochromatin protein expression levels but show enlarged nuclei. Dicer-deficient NSCs display abnormal differentiation and undergo cell death when mitogens are withdrawn. Dicer deletion affects the levels of many proteins, as revealed by a mass spectrometry proteomic approach. We have found that an increase of anti-survival and/or pro-apoptosis proteins and a decrease of pro-survival and/or anti-apoptosis proteins contribute to the cell death of Dicer-deficient NSCs, implying a general role for Dicer in protecting cells from apoptosis. Our results demonstrate important functions for Dicer in regulating NSC development by maintaining proper signaling pathways related to cell survival and differentiation.


Assuntos
Córtex Cerebral/citologia , Córtex Cerebral/enzimologia , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/enzimologia , Neurônios/citologia , Neurônios/enzimologia , Ribonuclease III/metabolismo , Animais , Apoptose , Sequência de Bases , Diferenciação Celular , Núcleo Celular/ultraestrutura , Sobrevivência Celular , Córtex Cerebral/embriologia , Primers do DNA/genética , Feminino , Heterocromatina/metabolismo , Cariotipagem , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Modelos Neurológicos , Gravidez , Análise Serial de Proteínas , Ribonuclease III/deficiência , Ribonuclease III/genética , Transdução de Sinais
18.
Blood ; 109(10): 4174-80, 2007 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-17289807

RESUMO

Ferroportin disease is caused by mutation of one allele of the iron exporter ferroportin (Fpn/IREG1/Slc40a1/MTP1). All reported human mutations are missense mutations and heterozygous null mutations in mouse Fpn do not recapitulate the human disease. Here we describe the flatiron (ffe) mouse with a missense mutation (H32R) in Fpn that affects its localization and iron export activity. Similar to human patients with classic ferroportin disease, heterozygous ffe/+ mice present with iron loading of Kupffer cells, high serum ferritin, and low transferrin saturation. In macrophages isolated from ffe/+ heterozygous mice and through the use of Fpn plasmids with the ffe mutation, we show that Fpn(ffe) acts as a dominant negative, preventing wild-type Fpn from localizing on the cell surface and transporting iron. These results demonstrate that mutations in Fpn resulting in protein mislocalization act in a dominant-negative fashion to cause disease, and the Fpn(ffe) mouse represents the first mouse model of ferroportin disease.


Assuntos
Proteínas de Transporte de Cátions/genética , Distúrbios do Metabolismo do Ferro/genética , Mutação , Animais , Sequência de Bases , Proteínas de Transporte de Cátions/metabolismo , Células Cultivadas , Análise Mutacional de DNA , Genes Dominantes , Humanos , Ferro/metabolismo , Distúrbios do Metabolismo do Ferro/embriologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Transporte Proteico
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