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1.
Rinsho Ketsueki ; 60(7): 800-809, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31391370

RESUMO

In myeloid neoplasms, deletions of the long arm of chromosome 5 del(5q) and 7 (-7/del(7q) ) are common karyotypic abnormalities. The concurrence of del(5q) and -7/del(7q) accounts for poor prognosis in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Comprehensive analysis of copy number abnormalities and genetic mutations related to del(5q) and -7/del(7q) revealed previously cryptic pathophysiology, leading to frequent hemizygous/homozygous mutations and haploinsufficiency. In addition, detailed somatic mutations on chr5q were detected using whole-exome sequencing. CSNK1A1 and G3BP1 are located within the common deleted regions (CDRs) (5q31.1-5q33.1), and another driver gene DDX41 is present in the more telomeric region (5q35.3). All the genes mentioned above exhibited haploinsufficiency because of deletions, and low expression of G3BP1 and DDX41 correlated with poor survival. The related mutational events outside of chr5q, TP53 mutation is most frequently observed in del(5q) cases. Regarding -7/del(7q), 3 CDRs were located in 7q22, 7q34, and 7q35-36. Somatic mutations of the corresponding genes to each CDR (CUX1: 7q22, LUC7L2: 7q34, EZH2: 7q35-36) were identified, indicating that the loss of function or haploinsufficiency might result in the downstream pathological consequences. These recent findings have remarkably offered insights into genetic and clinical consequences in MDS/AML cases with del(5q) and -7/del(7q).


Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 5/genética , Cromossomos Humanos Par 7/genética , Leucemia Mieloide Aguda/genética , RNA Helicases DEAD-box/genética , DNA Helicases/genética , Humanos , Proteínas de Ligação a Poli-ADP-Ribose/genética , RNA Helicases/genética , Proteínas com Motivo de Reconhecimento de RNA/genética
2.
Life Sci ; 232: 116656, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31306658

RESUMO

AIMS: Tamoxifen-induced liver-specific Dicer1 deletion (iDicer1-/-) in mature mice may provide clues demonstrating the genuine effects of acute loss of Dicer1 and miRNAs in the liver regeneration process. MAIN METHODS: In this study, mice with tamoxifen-induced Dicer1 deletion through the Cre/LoxP system were constructed and then underwent classic 70% partial hepatectomy or CCl4-induced liver injury. To rescue the inhibitory effect of Dicer1 ablation on liver regeneration, miR-21 agomir was injected into the tail vein of iDicer1-/- mice. KEY FINDINGS: Unlike constitutive embryonic deletion of Dicer1, tamoxifen-induced Dicer1 deletion did not result in severe liver injury or lesions, providing an ideal model for investigating acute loss of Dicer1 and miRNAs in liver regeneration. Dicer1 deletion led to impaired liver regeneration through the inhibitory effect of miR-21 on PTEN and Rhob expression. SIGNIFICANCE: In our previous study, we found that embryonic loss of Dicer1 impairs hepatocyte survival and leads to chronic inflammation and progenitor cell activation, while the role of Dicer1 in liver regeneration remains largely unknown. We clearly identified the promotion effect of Dicer1 on liver regeneration by increasing miR-21 expression, which inhibits the expression of two negative cell proliferation regulators, Pten and Rhob.


Assuntos
RNA Helicases DEAD-box/fisiologia , Regeneração Hepática/fisiologia , MicroRNAs/fisiologia , PTEN Fosfo-Hidrolase/metabolismo , Ribonuclease III/fisiologia , Proteína rhoB de Ligação ao GTP/metabolismo , Animais , RNA Helicases DEAD-box/genética , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Camundongos , Camundongos Knockout , Ribonuclease III/genética , Tamoxifeno/administração & dosagem
3.
Artigo em Inglês | MEDLINE | ID: mdl-31176867

RESUMO

In rice field eel (Monopterus albus), germ cell development in the developing gonad has been revealed in detail. However, it is unclear how primordial germ cells (PGCs) migrate to the somatic part of the gonad (genital ridge). This study visualized PGC migration by injecting a chimeric mRNA containing a fluorescent protein fused to the 3' untranslated region (3'UTR) of three different genes, nanos3 of zebrafish (Danio rerio) and dead end (dnd) and vasa of rice field eel. The mRNAs were injected either alone or in pairs into embryos at the one-cell stage. The results showed that mRNAs containing nanos3 and dnd 3'UTRs labeled PGCs over a wider time frame than those containing vasa 3'UTR, suggesting that nanos3 and dnd 3'UTRs are suitable for visualizing PGCs in rice field eel. Using this direct visualization method, the normal migration route of PGCs was observed from the 50%-epiboly stage to hatching stage for the first time, and the ectopic PGCs were also visualized during this period in rice field eel. These findings extend our knowledge of germ cell development, and lay a foundation for further research on the relationship between PGCs and sex differentiation, and on incubation conditions for embryos in rice field eel.


Assuntos
Células Germinativas/metabolismo , Smegmamorpha/embriologia , Regiões 3' não Traduzidas , Sequência de Aminoácidos , Animais , Movimento Celular/genética , Movimento Celular/fisiologia , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Feminino , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Células Germinativas/citologia , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Masculino , RNA/genética , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Homologia de Sequência de Aminoácidos , Smegmamorpha/genética , Smegmamorpha/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
4.
Nat Commun ; 10(1): 2278, 2019 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-31123254

RESUMO

Mammalian spermatogenesis is sustained by mitotic germ cells with self-renewal potential known as undifferentiated spermatogonia. Maintenance of undifferentiated spermatogonia and spermatogenesis is dependent on tightly co-ordinated transcriptional and post-transcriptional mechanisms. The RNA helicase DDX5 is expressed by spermatogonia but roles in spermatogenesis are unexplored. Using an inducible knockout mouse model, we characterise an essential role for DDX5 in spermatogonial maintenance and show that Ddx5 is indispensable for male fertility. We demonstrate that DDX5 regulates appropriate splicing of key genes necessary for spermatogenesis. Moreover, DDX5 regulates expression of cell cycle genes in undifferentiated spermatogonia post-transcriptionally and is required for cell proliferation and survival. DDX5 can also act as a transcriptional co-activator and we demonstrate that DDX5 interacts with PLZF, a transcription factor required for germline maintenance, to co-regulate select target genes. Combined, our data reveal a critical multifunctional role for DDX5 in regulating gene expression programmes and activity of undifferentiated spermatogonia.


Assuntos
RNA Helicases DEAD-box/metabolismo , Proteína com Dedos de Zinco da Leucemia Promielocítica/metabolismo , Processamento de RNA/fisiologia , Espermatogênese/genética , Espermatogônias/metabolismo , Animais , Ciclo Celular/genética , Proliferação de Células/genética , Técnicas de Cocultura , RNA Helicases DEAD-box/genética , Embrião de Mamíferos , Fertilidade/genética , Fibroblastos , Regulação da Expressão Gênica/fisiologia , Masculino , Camundongos , Camundongos Knockout , Modelos Animais , Cultura Primária de Células , Testículo/citologia
5.
Indian J Ophthalmol ; 67(6): 755-762, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31124483

RESUMO

Intraocular medulloepithelioma is a nonhereditary neoplasm of childhood arising from primitive medullary epithelium. It most often involves the ciliary body. Most patients present between 2 and 10 years of age with loss of vision, pain, leucocoria, or conjunctival congestion. The mass appears as a grey-white ciliary body lesion with intratumoral cysts. Presence of a neoplastic cyclitic membrane with extension to retrolental region is characteristic. Secondary manifestations like cataract and neovascular glaucoma may be present in up to 50% and 60% patients, respectively. These could be the first signs for which, unfortunately, about 50% patients undergo surgery before recognition of the hidden tumor. Systemic correlation with pleuropulmonary blastoma (DICER1 gene) has been documented in 5% cases. Histopathology shows primitive neuroepithelial cells arranged as cords closely resembling the primitive retina. Histopathologically, the tumor is classified as teratoid (containing heteroplastic elements) and nonteratoid (containing medullary epithelial elements), each of which are further subclassified as benign or malignant. Retinoblastoma-like and sarcoma-like areas may be seen within the tissue. The treatment modality depends on tumor size and extent of invasion. For small localized tumors (≤3-4 clock hours), conservative treatments with cryotherapy, plaque radiotherapy, or partial lamellar sclerouvectomy (PLSU) have been used. Plaque brachytherapy is generally preferred for best tumor control. Advanced and extensive tumors require enucleation. Rare use of intra-arterial and intravitreal chemotherapy has been employed. Systemic prognosis is favorable, but those with extraocular extension and orbital involvement show risk for local recurrence and metastatic disease, which can lead to death.


Assuntos
RNA Helicases DEAD-box/genética , DNA de Neoplasias/genética , Gerenciamento Clínico , Neoplasias Oculares , Mutação , Tumores Neuroectodérmicos Primitivos , Ribonuclease III/genética , Terapia Combinada , Neoplasias Oculares/diagnóstico , Neoplasias Oculares/genética , Neoplasias Oculares/terapia , Humanos , Tumores Neuroectodérmicos Primitivos/diagnóstico , Tumores Neuroectodérmicos Primitivos/genética , Tumores Neuroectodérmicos Primitivos/terapia
6.
N Engl J Med ; 380(19): 1834-1842, 2019 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-31067372

RESUMO

Mesenchymal hamartoma of the liver (MHL) is a benign tumor affecting children that is characterized by a primitive myxoid stroma with cystically dilated bile ducts. Alterations involving chromosome 19q13 are a recurrent underlying cause of MHL; these alterations activate the chromosome 19 microRNA cluster (C19MC). Other cases remain unexplained. We describe two children with MHLs that harbored germline DICER1 pathogenic variants. Analysis of tumor tissue from one of the children revealed two DICER1 "hits." Mutations in DICER1 dysregulate microRNAs, mimicking the effect of the activation of C19MC. Our data suggest that MHL is a new phenotype of DICER1 syndrome. (Funded by the Canadian Institutes of Health Research and others.).


Assuntos
Cromossomos Humanos Par 19 , RNA Helicases DEAD-box/genética , Mutação em Linhagem Germinativa , Hamartoma/genética , Hepatopatias/genética , MicroRNAs/metabolismo , Síndromes Neoplásicas Hereditárias/genética , Ribonuclease III/genética , Pré-Escolar , Feminino , Predisposição Genética para Doença , Hamartoma/diagnóstico por imagem , Hamartoma/patologia , Humanos , Fígado/diagnóstico por imagem , Fígado/patologia , Hepatopatias/diagnóstico por imagem , Hepatopatias/patologia , Masculino , Mesoderma , Linhagem , Fenótipo
7.
Cell Physiol Biochem ; 52(5): 984-1002, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30977984

RESUMO

BACKGROUND/AIMS: The epithelial sodium channel (ENaC) expressed in alveolar epithelial cells plays a major role in lung liquid clearance at birth and lung edema resorption in adulthood. We showed previously that αENaC mRNA expression is downregulated in part via posttranscriptional regulation of mRNA stability. In the present work, the role of the αENaC 3' untranslated region (3'UTR) in the regulation of mRNA stability was studied further. METHODS: Quantitative reverse transcription PCR (qRT-PCR) was performed to investigate the expression of αENaC in alveolar epithelial cells. The role of the αENaC 3'UTR was evaluated through sequential deletions. RNA affinity chromatography and mass spectrometry were achieved to investigate the nature of the proteins that could bind this sequence. The function of these proteins was assessed through knockdown and overexpression in vitro. RESULTS: First, we found that αENaC mRNA half-life was much shorter than expected when using a transcriptionally controlled plasmid expression system compared to Actinomycin D treatment. Sequential deletions of the αENaC 3'UTR revealed that the αENaC 3'UTR plays an important role in the modulation of αENaC mRNA stability, and that there is a complex stabilizing and destabilizing interplay between different regions of the 3'UTR that modulate this process. Finally, we identified RNA-binding proteins that interact with the αENaC 3'UTR and showed that Dhx36 and Tial1 are involved in the decrease in αENaC mRNA stability via the proximal region of its 3'UTR. CONCLUSION: Taken together, these findings indicate that the αENaC 3'UTR plays an important role in modulating transcript levels, and Dhx36 and Tial1 seem to be involved in posttranscriptional regulation of αENaC expression in alveolar epithelial cells.


Assuntos
Regiões 3' não Traduzidas , Células Epiteliais/metabolismo , Canais Epiteliais de Sódio/biossíntese , Regulação da Expressão Gênica , Alvéolos Pulmonares/metabolismo , Estabilidade de RNA , Animais , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Células Epiteliais/citologia , Canais Epiteliais de Sódio/genética , Masculino , Alvéolos Pulmonares/citologia , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Ratos , Ratos Sprague-Dawley
8.
Nat Commun ; 10(1): 1855, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31015431

RESUMO

DHX36 is a DEAH-box helicase that resolves parallel G-quadruplex structures formed in DNA and RNA. The recent co-crystal structure of DHX36 bound G4-DNA revealed an intimate contact, but did not address the role of ATP hydrolysis in G4 resolving activity. Here, we demonstrate that unlike on G4-DNA, DHX36 displays ATP-independent unfolding of G4-RNA followed by ATP-dependent refolding, generating a highly asymmetric pattern of activity. Interestingly, DHX36 refolds G4-RNA in several steps, reflecting the discrete steps in forming the G4 structure. We show that the ATP-dependent activity of DHX36 arises from the RNA tail rather than the G4. Mutations that perturb G4 contact result in quick dissociation of the protein from RNA upon ATP hydrolysis, while mutations that interfere with binding the RNA tail induce dysregulated activity. We propose that the ATP-dependent activity of DHX36 may be useful for dynamically resolving various G4-RNA structures in cells.


Assuntos
Trifosfato de Adenosina/metabolismo , RNA Helicases DEAD-box/metabolismo , Quadruplex G , Dobramento de RNA , RNA/metabolismo , RNA Helicases DEAD-box/genética , Transferência Ressonante de Energia de Fluorescência/métodos , Humanos , Microscopia de Fluorescência/métodos , Mutagênese Sítio-Dirigida , Mutação , Ligação Proteica/genética , RNA/química , Imagem Individual de Molécula/métodos
9.
Nucleic Acids Res ; 47(7): 3699-3710, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-30993346

RESUMO

DEAD-box helicases are involved in all steps of RNA metabolism. They are ATP-dependent RNA binding proteins and RNA-dependent ATPases. They can displace short duplexes, but they lack processivity. Their mechanism and functioning are not clearly understood; classical or bulk biochemical assays are not sufficient to answer these questions. Single-molecule techniques provide useful tools, but they are limited in cases where the proteins are nonprocessive and give weak signals. We present here a new, magnetic-tweezers-based, single-molecule assay that is simple and that can sensitively measure the displacement time of a small, hybridized, RNA oligonucleotide. Tens of molecules can be analyzed at the same time. Comparing the displacement times with and without a helicase gives insights into the enzymatic activity of the protein. We used this assay to study yeast Ded1, which is orthologous to human DDX3. Although Ded1 acts on a variety of substrates, we find that Ded1 requires an RNA substrate for its ATP-dependent unwinding activity and that ATP hydrolysis is needed to see this activity. Further, we find that only intramolecular single-stranded RNA extensions enhance this activity. We propose a model where ATP-bound Ded1 stabilizes partially unwound duplexes and where multiple binding events may be needed to see displacement.


Assuntos
RNA Helicases DEAD-box/química , RNA/química , Proteínas de Saccharomyces cerevisiae/química , Adenosina Trifosfatases/química , Adenosina Trifosfatases/genética , Trifosfato de Adenosina/química , Trifosfato de Adenosina/genética , Sequência de Aminoácidos/genética , RNA Helicases DEAD-box/genética , Humanos , Fenômenos Mecânicos , RNA/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
10.
RNA ; 25(6): 685-701, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30910870

RESUMO

Eukaryotic ribosome biogenesis is a highly orchestrated process involving numerous assembly factors including ATP-dependent RNA helicases. The DEAH helicase DHX37 (Dhr1 in yeast) is activated by the ribosome biogenesis factor UTP14A to facilitate maturation of the small ribosomal subunit. We report the crystal structure of DHX37 in complex with single-stranded RNA, revealing a canonical DEAH ATPase/helicase architecture complemented by a structurally unique carboxy-terminal domain (CTD). Structural comparisons of the nucleotide-free DHX37-RNA complex with DEAH helicases bound to RNA and ATP analogs reveal conformational changes resulting in a register shift in the bound RNA, suggesting a mechanism for ATP-dependent 3'-5' RNA translocation. We further show that a conserved sequence motif in UTP14A interacts with and activates DHX37 by stimulating its ATPase activity and enhancing RNA binding. In turn, the CTD of DHX37 is required, but not sufficient, for interaction with UTP14A in vitro and is essential for ribosome biogenesis in vivo. Together, these results shed light on the mechanism of DHX37 and the function of UTP14A in controlling its recruitment and activity during ribosome biogenesis.


Assuntos
Adenosina Trifosfatases/química , Trifosfato de Adenosina/análogos & derivados , RNA Helicases DEAD-box/química , Biogênese de Organelas , RNA Helicases/química , RNA/química , Ribonucleoproteínas Nucleolares Pequenas/química , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Sítios de Ligação , Clonagem Molecular , Cristalografia por Raios X , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Cinética , Camundongos , Modelos Moleculares , Ligação Proteica , Biossíntese de Proteínas , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , RNA/metabolismo , RNA Helicases/genética , RNA Helicases/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Ribonucleoproteínas Nucleolares Pequenas/genética , Ribonucleoproteínas Nucleolares Pequenas/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Especificidade por Substrato
11.
Proc Natl Acad Sci U S A ; 116(12): 5687-5692, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30842276

RESUMO

Melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) is a multifunctional cytokine displaying broad-spectrum anticancer activity in vitro or in vivo in preclinical animal cancer models and in a phase 1/2 clinical trial in patients with advanced cancers. mda-7/IL-24 targets specific miRNAs, including miR-221 and miR-320, for down-regulation in a cancer-selective manner. We demonstrate that mda-7/IL-24, administered through a replication incompetent type 5 adenovirus (Ad.mda-7) or with His-MDA-7/IL-24 protein, down-regulates DICER, a critical regulator in miRNA processing. This effect is specific for mature miR-221, as it does not affect Pri-miR-221 expression, and the DICER protein, as no changes occur in other miRNA processing cofactors, including DROSHA, PASHA, or Argonaute. DICER is unchanged by Ad.mda-7/IL-24 in normal immortal prostate cells, whereas Ad.mda-7 down-regulates DICER in multiple cancer cells including glioblastoma multiforme and prostate, breast, lung, and liver carcinoma cells. MDA-7/IL-24 protein down-regulates DICER expression through canonical IL-20/IL-22 receptors. Gain- and loss-of-function studies confirm that overexpression of DICER rescues deregulation of miRNAs by mda-7/IL-24, partially rescuing cancer cells from mda-7/IL-24-mediated cell death. Stable overexpression of DICER in cancer cells impedes Ad.mda-7 or His-MDA-7/IL-24 inhibition of cell growth, colony formation, PARP cleavage, and apoptosis. In addition, stable overexpression of DICER renders cancer cells more resistant to Ad.mda-7 inhibition of primary and secondary tumor growth. MDA-7/IL-24-mediated regulation of DICER is reactive oxygen species-dependent and mediated by melanogenesis-associated transcription factor. Our research uncovers a distinct role of mda-7/IL-24 in the regulation of miRNA biogenesis through alteration of the MITF-DICER pathway.


Assuntos
RNA Helicases DEAD-box/metabolismo , Interleucinas/metabolismo , MicroRNAs/metabolismo , Fator de Transcrição Associado à Microftalmia/metabolismo , Ribonuclease III/metabolismo , Animais , Apoptose/fisiologia , Diferenciação Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , RNA Helicases DEAD-box/biossíntese , RNA Helicases DEAD-box/genética , Regulação para Baixo , Genes Supressores de Tumor , Humanos , Interleucinas/genética , Masculino , Camundongos , Camundongos Nus , MicroRNAs/biossíntese , Fator de Transcrição Associado à Microftalmia/genética , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/parasitologia , Espécies Reativas de Oxigênio/metabolismo , Ribonuclease III/biossíntese , Ribonuclease III/genética , Transdução de Sinais , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
13.
Mol Genet Genomic Med ; 7(5): e639, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30924321

RESUMO

BACKGROUND: Warsaw Breakage Syndrome (WABS) is an ultra rare cohesinopathy caused by biallelic mutation of DDX11 gene. It is clinically characterized by pre and postnatal growth delay, microcephaly, hearing loss with cochlear hypoplasia, skin color abnormalities, and dysmorphisms. METHODS: Mutational screening and functional analyses (protein expression and 3D-modeling) were performed in order to investigate the presence and pathogenicity of DDX11 variant identified in our patients. RESULTS: We report the clinical history of two sisters affected by WABS with a pathological mytomicin C test carrying compound heterozygous mutations (c.2507T > C / c.907_920del) of the DDX11 gene. The pathogenicity of this variant was confirmed in the light of a bioinformatic study and protein three-dimensional modeling, as well as expression analysis. CONCLUSION: These findings further extend the clinical and molecular knowledge about the WABS showing a possible mild phenotype without major malformations or intellectual disability.


Assuntos
Anormalidades Múltiplas/genética , Manchas Café com Leite/genética , RNA Helicases DEAD-box/genética , DNA Helicases/genética , Perda Auditiva Neurossensorial/genética , Fenótipo , Anormalidades Múltiplas/patologia , Manchas Café com Leite/patologia , Linhagem Celular , Células Cultivadas , Criança , Pré-Escolar , Feminino , Perda Auditiva Neurossensorial/patologia , Humanos , Mutação , Síndrome
14.
Methods Mol Biol ; 1932: 261-283, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30701507

RESUMO

MicroRNAs (miRNA) are small RNAs of 20-22 nt that regulate diverse biological pathways through the modulation of gene expression. miRNAs recognize target RNAs by base complementarity and guide them to degradation or translational arrest. They are transcribed as longer precursors with extensive secondary structures. In plants, these precursors are processed by a complex harboring DICER-LIKE1 (DCL1), which cuts on the precursor stem region to release the mature miRNA together with the miRNA*. In both plants and animals, the miRNA precursors contain spatial clues that determine the position of the miRNA along their sequences. DCL1 is assisted by several proteins, such as the double-stranded RNA binding protein, HYPONASTIC LEAVES1 (HYL1), and the zinc finger protein SERRATE (SE). The precise biogenesis of miRNAs is of utter importance since it determines the exact nucleotide sequence of the mature small RNAs and therefore the identity of the target genes. miRNA processing itself can be regulated and therefore can determine the final small RNA levels and activity. Here, we describe methods to analyze miRNA processing intermediates in plants. These approaches can be used in wild-type or mutant plants, as well as in plants grown under different conditions, allowing a molecular characterization of the miRNA biogenesis from the RNA precursor perspective.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , MicroRNAs/genética , RNA de Plantas/genética , RNA Helicases DEAD-box/genética , Precursores de RNA/genética , Proteínas de Ligação a RNA/genética , Proteínas Serrate-Jagged/genética
15.
Crit Rev Biotechnol ; 39(3): 395-407, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30714414

RESUMO

Diverse abiotic stresses constitute one of the major factors which adversely affect the normal plant growth and development which results worldwide in decreased agricultural productivity. At present, utilization of new molecular tools to achieve improved stress tolerance and increased crop productivity is highly desirable. Abiotic stress in plants induces expression of a wide range of genes like transcription factors, defense related genes and so on, and the products of these genes are important in combating stress conditions. Helicases are one such category of proteins that play a key role in maintaining the genomic integrity of the cell by participating in nucleic acid mediated processes such as recombination, replication, and repair of DNA as well as the unwinding of misfolded RNA structures that are formed during stress conditions. The DEAD box helicases are a subgroup of helicases which contain the amino acids Asp-Glu-Ala-Asp (DEAD) and are involved in the above molecular functions that mediate adaptation to stress. Overexpression of DEAD box helicases is known to provide stress tolerance in various plants and thus their use in developing stress tolerant plants is gaining importance. The plausible physiological mechanisms of helicases in bestowing abiotic stress tolerance of plants include ROS scavenging, enhanced photosynthesis, ion homeostasis and regulation of various stress responsive genes. In this review, the characteristics of plant DEAD box helicases and the stress conditions under which they express are discussed. We have provided a detailed description on the transgenic plants overexpressing DEAD box helicases with an emphasis on their stress tolerance abilities.


Assuntos
Adaptação Fisiológica/genética , RNA Helicases DEAD-box/genética , Plantas Geneticamente Modificadas/genética , Estresse Fisiológico/genética , RNA Helicases DEAD-box/química , Regulação da Expressão Gênica de Plantas/genética , Fotossíntese/genética , Plantas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Salinidade
16.
BMJ Case Rep ; 12(1)2019 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-30665929

RESUMO

Pleuropulmonary blastomas (PPB) are rare aggressive paediatric lung malignancies associated with DICER1 variants. We present two cases, a 2-year-old girl with upper respiratory tract symptoms as well as a 6-month-old girl sibling undergoing screening due to family history of malignancy. Imaging of the 2-year-old girl revealed a large mass filling the right hemithorax which was determined to be a type II PPB after pathological examination. Imaging of the 6-month-old sibling demonstrated a small cystic lesion in the posterior basal segment of the right lower lobe which was determined to be a type 1r PPB after pathological examination. The 2-year-old girl received adjuvant chemotherapy while the baby sister underwent resection alone and both are alive and well at 12 months and 7 months, respectively. Sequence analysis in both cases confirmed the same DICER1 variation, c.2437-2A>G (likely pathogenic), which has not been previously described in the literature.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , RNA Helicases DEAD-box/genética , Mutação Puntual , Blastoma Pulmonar/terapia , Procedimentos Cirúrgicos Pulmonares/métodos , Ribonuclease III/genética , Quimioterapia Adjuvante , Pré-Escolar , Diagnóstico Diferencial , Feminino , Humanos , Lactente , Íntrons , Blastoma Pulmonar/diagnóstico por imagem , Blastoma Pulmonar/genética , Análise de Sequência de DNA , Irmãos , Resultado do Tratamento
17.
Mol Genet Genomic Med ; 7(3): e555, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30672147

RESUMO

BACKGROUND: The DICER1 syndrome is an autosomal dominant tumor-predisposition disorder associated with pleuropulmonary blastoma, a rare pediatric lung cancer. Somatic missense variation in "hotspot" codons in the RNaseIIIb domain (E1705, D1709, G1809, D1810, E1813) is observed in DICER1-associated tumors. Previously, we found the prevalence of germline pathogenic DICER1 variation in the general population is 1:10,600. In this study, we investigated the prevalence of pathogenic DICER1 germline variation in The Cancer Genome Atlas (TCGA; 32 adult cancer types; 9,173 exomes) and the Therapeutically Applicable Research to Generate Effective Treatment (TARGET; two pediatric cancer types; 175 exomes) cohorts. METHODS: All datasets were annotated and binned into four categories: pathogenic, likely pathogenic, variant of unknown significance, or likely benign. RESULTS: The prevalence of DICER1 pathogenic variants was 1:4,600 in TCGA. A single participant with a uterine corpus endometrial carcinoma harbored two pathogenic germline DICER1 (hotspot and splice-donor) variants, and a single participant with a rectal adenocarcinoma harbored a germline DICER1 stop-gained variant. In the smaller TARGET dataset, we observed no pathogenic germline variants. CONCLUSION: This is the largest comprehensive analysis of DICER1 pathogenic variation in adult and pediatric cancer populations using publicly available data. The observation of germline DICER1 variation with uterine corpus endometrial carcinoma merits additional investigation.


Assuntos
RNA Helicases DEAD-box/genética , Mutação em Linhagem Germinativa , Neoplasias/genética , Polimorfismo Genético , Ribonuclease III/genética , Conjuntos de Dados como Assunto , Humanos
18.
J Reprod Dev ; 65(2): 121-128, 2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-30613052

RESUMO

About 10% of male infertile patients show abnormalities in spermatogenesis. The microdeletion of azoospermia factor a (AZFa) region of the Y chromosome is thought to be a cause of spermatogenic failure. However, candidate gene responsible for the spermatogenic failure in AZFa deleted patients has not been elucidated yet. Using mice, we explored the function of Ddx3y, a strong candidate gene in the Azfa region, and Ddx3x, a Ddx3y paralog on the X chromosome, in spermatogenesis. We first generated Ddx3y KO male mice using CRISPR/Cas9 and found that the Ddx3y KO male mice show normal spermatogenesis, produce morphologically normal spermatozoa, and sire healthy offspring. Because Ddx3x KO males were embryonic lethal, we next generated chimeric mice, which contain Ddx3x and Ddx3y double KO (dKO) germ cells, and found that the dKO germ cells can differentiate into spermatozoa and transmit their mutant alleles to offspring by normal mating. We conclude that Ddx3x and Ddx3y are dispensable for spermatogenesis at least in mice. Unlike human, mice have an additional Ddx3y paralog D1pas1, that has been reported to be essential for spermatogenesis. These findings suggest that human and mouse DDX3 related proteins have distinct differences in their functions.


Assuntos
Azoospermia/genética , RNA Helicases DEAD-box/genética , Fertilidade/genética , Células Germinativas/metabolismo , Antígenos de Histocompatibilidade Menor/genética , RNA Helicases/genética , Animais , RNA Helicases DEAD-box/metabolismo , Desenvolvimento Embrionário/genética , Feminino , Fertilização In Vitro , Infertilidade Masculina/genética , Infertilidade Masculina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Antígenos de Histocompatibilidade Menor/metabolismo , RNA Helicases/metabolismo , Homologia de Sequência , Espermatogênese/genética , Espermatozoides/metabolismo
19.
Oncogene ; 38(18): 3446-3457, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30643190

RESUMO

Hepatocellular carcinoma (HCC) is generally accompanied by high mortality and low cure rate. CCAAT enhancer-binding proteins (CEBPs) are transcriptional regulators that play a key role in maintaining liver function. Altered expression of C/EBPα and C/EBPß occurs in many tumours including HCC. saRNAs are small double-stranded RNAs that enhance target gene expression at the transcriptional level. In this report, we activate CEPBA with saRNAs and suppress CEBPB with siRNAs in cells that represent three different degrees of HCC. We performed functional assays to investigate the effects of enhancing C/EBPα and its downstream targets, p21 and albumin across these lines. We also used Mass-spectrometry (MS) subsequent to a ChIP pull-down assay to characterise the components of the protein complex involved in regulating saRNA function. Putative saRNA interacting protein candidates that were identified by MS were knocked-down with siRNAs to investigate its impact on saRNA activity. We confirmed CEBPA-saRNA decreased proliferation and migration in the differentiated lines (HepG3/Hep3B). The undifferentiated line (PLCPRF5) showed saRNA-induced increase in CEBPA but with no loss in proliferation. This effect was reversed when CEBPB was suppressed with CEBPB-siRNA. When interrogating saRNA mode of action; three saRNA interacting proteins, CTR9, HnRNPA2/B1 and DDX5 were identified by MS. Targeted knock-down of these two proteins (by siRNA) abrogated saRNA activity. This study provides insight into how different HCC lines are affected by CEBPA-saRNAs and that endogenous abundance of CEBPB and saRNA accessory proteins may dictate efficacy of CEBPA-saRNA when used in a therapeutic context.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/genética , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , RNA Interferente Pequeno/genética , Diferenciação Celular/genética , Linhagem Celular Tumoral , RNA Helicases DEAD-box/genética , Regulação da Expressão Gênica/genética , Células Hep G2 , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/genética , Humanos , Proteínas Nucleares/genética
20.
J Exp Clin Cancer Res ; 38(1): 9, 2019 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-30621721

RESUMO

BACKGROUND: RNA binding proteins (RBPs) have been reported to interact with RNAs to regulate gene expression. Circular RNAs (circRNAs) are a type of endogenous non-coding RNAs, which involved in the angiogenesis of tumor. The purpose of this study is to elucidate the potential roles and molecular mechanisms of MOV10 and circ-DICER1 in regulating the angiogenesis of glioma-exposed endothelial cells (GECs). METHODS: The expressions of circ-DICER1, miR-103a-3p and miR-382-5p were detected by real-time PCR. The expressions of MOV10, ZIC4, Hsp90 and PI3K/Akt were detected by real-time PCR or western blot. The binding ability of circ-SHKBP1 and miR-544a / miR-379, ZIC4 and miR-544a / miR-379 were analyzed with Dual-Luciferase Reporter System or RIP experiment. The direct effects of ZIC4 on the Hsp90ß promoter were analyzed by the ChIP experiment. The cell viability, migration and tube formation in vitro were detected by CCK-8, Transwell assay and Matrigel tube formation assay. The angiogenesis in vivo was evaluated by Matrigel plug assay. Student's t-test (two tailed) was used for comparisons between two groups. One-way analysis of variance (ANOVA) was used for multi-group comparisons followed by Bonferroni post-hoc analysis. RESULTS: The expressions of RNA binding proteins MOV10, circ-DICER1, ZIC4, and Hsp90ß were up-regulated in GECs, while miR103a-3p/miR-382-5p were down-regulated. MOV10 binding circ-DICER1 regulated the cell viability, migration, and tube formation of GECs. And the effects of both MOV10 and circ-DICER1 silencing were better than the effects of MOV10 or circ-DICER1 alone silencing. In addition, circ-DICER1 acts as a molecular sponge to adsorb miR-103a-3p / miR-382-5p and impair the negative regulation of miR-103a-3p / miR-382-5p on ZIC4 in GECs. Furthermore, ZIC4 up-regulates the expression of its downstream target Hsp90ß, and Hsp90 promotes the cell viability, migration, and tube formation of GECs by activating PI3K/Akt signaling pathway. CONCLUSIONS: MOV10 / circ-DICER1 / miR-103a-3p (miR-382-5p) / ZIC4 pathway plays a vital role in regulating the angiogenesis of glioma. Our findings not only provides novel mechanisms for the angiogenesis of glioma, but also provide potential targets for anti-angiogenesis therapies of glioma.


Assuntos
RNA Helicases DEAD-box/genética , Glioma/genética , MicroRNAs/metabolismo , Proteínas do Tecido Nervoso/metabolismo , RNA Helicases/genética , RNA Helicases/metabolismo , Ribonuclease III/genética , Fatores de Transcrição/metabolismo , Animais , Neoplasias Encefálicas/irrigação sanguínea , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Proliferação de Células/fisiologia , Córtex Cerebral/irrigação sanguínea , Glioma/irrigação sanguínea , Glioma/metabolismo , Glioma/patologia , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/genética , Neovascularização Patológica , Transfecção , Regulação para Cima
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