Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.613
Filtrar
1.
Proc Natl Acad Sci U S A ; 117(38): 23510-23518, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32907935

RESUMO

The coiled-coil domains of intermediate filament (IF) proteins are flanked by regions of low sequence complexity. Whereas IF coiled-coil domains assume dimeric and tetrameric conformations on their own, maturation of eight tetramers into cylindrical IFs is dependent on either "head" or "tail" domains of low sequence complexity. Here we confirm that the tail domain required for assembly of Drosophila Tm1-I/C IFs functions by forming labile cross-ß interactions. These interactions are seen in polymers made from the tail domain alone, as well as in assembled IFs formed by the intact Tm1-I/C protein. The ability to visualize such interactions in situ within the context of a discrete cellular assembly lends support to the concept that equivalent interactions may be used in organizing other dynamic aspects of cell morphology.


Assuntos
Proteínas de Filamentos Intermediários , Filamentos Intermediários , Animais , Drosophila/química , Drosophila/metabolismo , Proteínas de Filamentos Intermediários/química , Proteínas de Filamentos Intermediários/metabolismo , Proteínas de Filamentos Intermediários/ultraestrutura , Filamentos Intermediários/química , Filamentos Intermediários/metabolismo , Filamentos Intermediários/ultraestrutura , Ressonância Magnética Nuclear Biomolecular , Polimerização , Conformação Proteica
2.
Cell Prolif ; 53(10): e12899, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32896929

RESUMO

OBJECTIVES: Stem cell niche regulated the renewal and differentiation of germline stem cells (GSCs) in Drosophila. Previously, we and others identified a series of genes encoding ribosomal proteins that may contribute to the self-renewal and differentiation of GSCs. However, the mechanisms that maintain and differentiate GSCs in their niches were not well understood. MATERIALS AND METHODS: Flies were used to generate tissue-specific gene knockdown. Small interfering RNAs were used to knockdown genes in S2 cells. qRT-PCR was used to examine the relative mRNA expression level. TUNEL staining or flow cytometry assays were used to detect cell survival. Immunofluorescence was used to determine protein localization and expression pattern. RESULTS: Herein, using a genetic manipulation approach, we investigated the role of ribosomal protein S13 (RpS13) in testes and S2 cells. We reported that RpS13 was required for the self-renewal and differentiation of GSCs. We also demonstrated that RpS13 regulated cell proliferation and apoptosis. Mechanistically, we showed that RpS13 regulated the expression of ribosome subunits and could moderate the expression of the Rho1, DE-cad and Arm proteins. Notably, Rho1 imitated the phenotype of RpS13 in both Drosophila testes and S2 cells, and recruited cell adhesions, which was mediated by the DE-cad and Arm proteins. CONCLUSION: These findings uncover a novel mechanism of RpS13 that mediates Rho1 signals in the stem cell niche of the Drosophila testis.


Assuntos
Proteínas de Drosophila/metabolismo , Proteínas Ribossômicas/metabolismo , Transdução de Sinais , Testículo/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Animais , Apoptose , Adesão Celular , Diferenciação Celular , Proliferação de Células , Autorrenovação Celular , Drosophila/metabolismo , Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/genética , Células Germinativas/citologia , Masculino , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Proteínas Ribossômicas/antagonistas & inibidores , Proteínas Ribossômicas/genética , Nicho de Células-Tronco , Células-Tronco/citologia , Células-Tronco/metabolismo , Proteínas rho de Ligação ao GTP/antagonistas & inibidores , Proteínas rho de Ligação ao GTP/genética
3.
BMC Bioinformatics ; 21(Suppl 13): 385, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32938373

RESUMO

BACKGROUND: Network alignment is an efficient computational framework in the prediction of protein function and phylogenetic relationships in systems biology. However, most of existing alignment methods focus on aligning PPIs based on static network model, which are actually dynamic in real-world systems. The dynamic characteristic of PPI networks is essential for understanding the evolution and regulation mechanism at the molecular level and there is still much room to improve the alignment quality in dynamic networks. RESULTS: In this paper, we proposed a novel alignment algorithm, Twadn, to align dynamic PPI networks based on a strategy of time warping. We compare Twadn with the existing dynamic network alignment algorithm DynaMAGNA++ and DynaWAVE and use area under the receiver operating characteristic curve and area under the precision-recall curve as evaluation indicators. The experimental results show that Twadn is superior to DynaMAGNA++ and DynaWAVE. In addition, we use protein interaction network of Drosophila to compare Twadn and the static network alignment algorithm NetCoffee2 and experimental results show that Twadn is able to capture timing information compared to NetCoffee2. CONCLUSIONS: Twadn is a versatile and efficient alignment tool that can be applied to dynamic network. Hopefully, its application can benefit the research community in the fields of molecular function and evolution.


Assuntos
Algoritmos , Biologia Computacional/métodos , Drosophila/metabolismo , Mapas de Interação de Proteínas/genética , Proteínas/metabolismo , Animais , Humanos
5.
PLoS Comput Biol ; 16(8): e1008105, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32817654

RESUMO

Epithelial sheets define organ architecture during development. Here, we employed an iterative multiscale computational modeling and quantitative experimental approach to decouple direct and indirect effects of actomyosin-generated forces, nuclear positioning, extracellular matrix, and cell-cell adhesion in shaping Drosophila wing imaginal discs. Basally generated actomyosin forces generate epithelial bending of the wing disc pouch. Surprisingly, acute pharmacological inhibition of ROCK-driven actomyosin contractility does not impact the maintenance of tissue height or curved shape. Computational simulations show that ECM tautness provides only a minor contribution to modulating tissue shape. Instead, passive ECM pre-strain serves to maintain the shape independent from actomyosin contractility. These results provide general insight into how the subcellular forces are generated and maintained within individual cells to induce tissue curvature. Thus, the results suggest an important design principle of separable contributions from ECM prestrain and actomyosin tension during epithelial organogenesis and homeostasis.


Assuntos
Actomiosina/metabolismo , Epitélio/anatomia & histologia , Matriz Extracelular/metabolismo , Animais , Drosophila/anatomia & histologia , Drosophila/embriologia , Drosophila/metabolismo , Epitélio/metabolismo , Fosforilação , Asas de Animais/anatomia & histologia , Asas de Animais/embriologia , Asas de Animais/metabolismo
6.
BMC Bioinformatics ; 21(1): 323, 2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32693790

RESUMO

BACKGROUND: Protein-protein interactions (PPIs) are central to many biological processes. Considering that the experimental methods for identifying PPIs are time-consuming and expensive, it is important to develop automated computational methods to better predict PPIs. Various machine learning methods have been proposed, including a deep learning technique which is sequence-based that has achieved promising results. However, it only focuses on sequence information while ignoring the structural information of PPI networks. Structural information of PPI networks such as their degree, position, and neighboring nodes in a graph has been proved to be informative in PPI prediction. RESULTS: Facing the challenge of representing graph information, we introduce an improved graph representation learning method. Our model can study PPI prediction based on both sequence information and graph structure. Moreover, our study takes advantage of a representation learning model and employs a graph-based deep learning method for PPI prediction, which shows superiority over existing sequence-based methods. Statistically, Our method achieves state-of-the-art accuracy of 99.15% on Human protein reference database (HPRD) dataset and also obtains best results on Database of Interacting Protein (DIP) Human, Drosophila, Escherichia coli (E. coli), and Caenorhabditis elegans (C. elegan) datasets. CONCLUSION: Here, we introduce signed variational graph auto-encoder (S-VGAE), an improved graph representation learning method, to automatically learn to encode graph structure into low-dimensional embeddings. Experimental results demonstrate that our method outperforms other existing sequence-based methods on several datasets. We also prove the robustness of our model for very sparse networks and the generalization for a new dataset that consists of four datasets: HPRD, E.coli, C.elegan, and Drosophila.


Assuntos
Mapeamento de Interação de Proteínas/métodos , Animais , Caenorhabditis elegans/metabolismo , Simulação por Computador , Bases de Dados de Proteínas , Drosophila/metabolismo , Escherichia coli/metabolismo , Humanos , Aprendizado de Máquina , Redes Neurais de Computação
7.
Nat Commun ; 11(1): 3631, 2020 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-32686670

RESUMO

Macrophages are a major immune cell type infiltrating tumors and promoting tumor growth and metastasis. To elucidate the mechanism of macrophage recruitment, we utilize an overgrowth tumor model ("undead" model) in larval Drosophila imaginal discs that are attached by numerous macrophages. Here we report that changes to the microenvironment of the overgrown tissue are important for recruiting macrophages. First, we describe a correlation between generation of reactive oxygen species (ROS) and damage of the basement membrane (BM) in all neoplastic, but not hyperplastic, models examined. ROS and the stress kinase JNK mediate the accumulation of matrix metalloproteinase 2 (Mmp2), damaging the BM, which recruits macrophages to the tissue. We propose a model where macrophage recruitment to and activation at overgrowing tissue is a multi-step process requiring ROS- and JNK-mediated Mmp2 upregulation and BM damage. These findings have implications for understanding the role of the tumor microenvironment for macrophage activation.


Assuntos
Membrana Basal/patologia , Ativação de Macrófagos/fisiologia , Metaloproteinase 2 da Matriz , Microambiente Tumoral/fisiologia , Animais , Membrana Basal/metabolismo , Proliferação de Células , Modelos Animais de Doenças , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Expressão Gênica , Discos Imaginais/imunologia , Discos Imaginais/metabolismo , Larva/metabolismo , MAP Quinase Quinase 4/metabolismo , Macrófagos/metabolismo , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 2 da Matriz/metabolismo , Espécies Reativas de Oxigênio/metabolismo
8.
PLoS One ; 15(6): e0234744, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32542037

RESUMO

Developmental processes require strict regulation of proliferation, differentiation and patterning for the generation of final organ size. Aberrations in these fundamental events are critically important in tumorigenesis and cancer progression. Salt inducible kinases (Siks) are evolutionarily conserved genes involved in diverse biological processes, including salt sensing, metabolism, muscle, cartilage and bone formation, but their role in development remains largely unknown. Recent findings implicate Siks in mitotic control, and in both tumor suppression and progression. Using a tumor model in the Drosophila eye, we show that perturbation of Sik function exacerbates tumor-like tissue overgrowth and metastasis. Furthermore, we show that both Drosophila Sik genes, Sik2 and Sik3, function in eye development processes. We propose that an important target of Siks may be the Notch signaling pathway, as we demonstrate genetic interaction between Siks and Notch pathway members. Finally, we investigate Sik expression in the developing retina and show that Sik2 is expressed in all photoreceptors, basal to cell junctions, while Sik3 appears to be expressed specifically in R3/R4 cells in the developing eye. Combined, our data suggest that Sik genes are important for eye tissue specification and growth, and that their dysregulation may contribute to tumor formation.


Assuntos
Drosophila/enzimologia , Drosophila/crescimento & desenvolvimento , Proteínas Serina-Treonina Quinases/metabolismo , Receptores Notch/metabolismo , Retina/crescimento & desenvolvimento , Animais , Drosophila/metabolismo , Ligação Proteica , Retina/metabolismo
9.
Nat Commun ; 11(1): 2943, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32523050

RESUMO

Aging is characterized by a chronic, low-grade inflammation, which is a major risk factor for cardiovascular diseases. It remains poorly understood whether pro-inflammatory factors released from non-cardiac tissues contribute to the non-autonomous regulation of age-related cardiac dysfunction. Here, we report that age-dependent induction of cytokine unpaired 3 (upd3) in Drosophila oenocytes (hepatocyte-like cells) is the primary non-autonomous mechanism for cardiac aging. We show that upd3 is significantly up-regulated in aged oenocytes. Oenocyte-specific knockdown of upd3 is sufficient to block aging-induced cardiac arrhythmia. We further show that the age-dependent induction of upd3 is triggered by impaired peroxisomal import and elevated JNK signaling in aged oenocytes. We term hormonal factors induced by peroxisome dysfunction as peroxikines. Intriguingly, oenocyte-specific overexpression of Pex5, the key peroxisomal import receptor, blocks age-related upd3 induction and alleviates cardiac arrhythmicity. Thus, our studies identify an important role of hepatocyte-specific peroxisomal import in mediating non-autonomous regulation of cardiac aging.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Peroxissomos/metabolismo , Animais , Transporte Proteico , Transdução de Sinais/fisiologia
10.
Nat Commun ; 11(1): 2228, 2020 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-32376880

RESUMO

Cell competition is an emerging principle that eliminates suboptimal or potentially dangerous cells. For 'unfit' cells to be detected, their competitive status needs to be compared to the collective fitness of cells within a tissue. Here we report that the NMDA receptor controls cell competition of epithelial cells and Myc supercompetitors in the Drosophila wing disc. While clonal depletion of the NMDA receptor subunit NR2 results in their rapid elimination via the TNF/Eiger>JNK signalling pathway, local over-expression of NR2 causes NR2 cells to acquire supercompetitor-like behaviour that enables them to overtake the tissue through clonal expansion that causes, but also relies on, the killing of surrounding cells. Consistently, NR2 is utilised by Myc clones to provide them with supercompetitor status. Mechanistically, we find that the JNK>PDK signalling axis in 'loser' cells reprograms their metabolism, driving them to produce and transfer lactate to winners. Preventing lactate transfer from losers to winners abrogates NMDAR-mediated cell competition. Our findings demonstrate a functional repurposing of NMDAR in the surveillance of tissue fitness.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Células Epiteliais/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Fatores de Transcrição/metabolismo , Asas de Animais/metabolismo , Animais , Apoptose/genética , Drosophila/genética , Proteínas de Drosophila/genética , Ácido Láctico/metabolismo , Sistema de Sinalização das MAP Quinases/genética , Mitocôndrias/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Transdução de Sinais/genética , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Asas de Animais/crescimento & desenvolvimento
11.
Cell Mol Life Sci ; 77(22): 4523-4551, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32448994

RESUMO

Organisms adapt to changing environments by adjusting their development, metabolism, and behavior to improve their chances of survival and reproduction. To achieve such flexibility, organisms must be able to sense and respond to changes in external environmental conditions and their internal state. Metabolic adaptation in response to altered nutrient availability is key to maintaining energy homeostasis and sustaining developmental growth. Furthermore, environmental variables exert major influences on growth and final adult body size in animals. This developmental plasticity depends on adaptive responses to internal state and external cues that are essential for developmental processes. Genetic studies have shown that the fruit fly Drosophila, similarly to mammals, regulates its metabolism, growth, and behavior in response to the environment through several key hormones including insulin, peptides with glucagon-like function, and steroid hormones. Here we review emerging evidence showing that various environmental cues and internal conditions are sensed in different organs that, via inter-organ communication, relay information to neuroendocrine centers that control insulin and steroid signaling. This review focuses on endocrine regulation of development, metabolism, and behavior in Drosophila, highlighting recent advances in the role of the neuroendocrine system as a signaling hub that integrates environmental inputs and drives adaptive responses.


Assuntos
Adaptação Fisiológica/fisiologia , Drosophila/metabolismo , Drosophila/fisiologia , Animais , Proteínas de Drosophila/metabolismo , Homeostase/fisiologia , Humanos , Hormônios de Inseto/metabolismo , Transdução de Sinais/fisiologia
12.
Proc Natl Acad Sci U S A ; 117(24): 13757-13766, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32467161

RESUMO

Inhaled anesthetics are a chemically diverse collection of hydrophobic molecules that robustly activate TWIK-related K+ channels (TREK-1) and reversibly induce loss of consciousness. For 100 y, anesthetics were speculated to target cellular membranes, yet no plausible mechanism emerged to explain a membrane effect on ion channels. Here we show that inhaled anesthetics (chloroform and isoflurane) activate TREK-1 through disruption of phospholipase D2 (PLD2) localization to lipid rafts and subsequent production of signaling lipid phosphatidic acid (PA). Catalytically dead PLD2 robustly blocks anesthetic TREK-1 currents in whole-cell patch-clamp recordings. Localization of PLD2 renders the TRAAK channel sensitive, a channel that is otherwise anesthetic insensitive. General anesthetics, such as chloroform, isoflurane, diethyl ether, xenon, and propofol, disrupt lipid rafts and activate PLD2. In the whole brain of flies, anesthesia disrupts rafts and PLDnull flies resist anesthesia. Our results establish a membrane-mediated target of inhaled anesthesia and suggest PA helps set thresholds of anesthetic sensitivity in vivo.


Assuntos
Anestésicos Inalatórios/administração & dosagem , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/genética , Membrana Celular/metabolismo , Clorofórmio/administração & dosagem , Drosophila/efeitos dos fármacos , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Isoflurano/administração & dosagem , Ácidos Fosfatídicos/metabolismo , Fosfolipase D/genética , Fosfolipase D/metabolismo , Canais de Potássio/genética , Canais de Potássio/metabolismo , Canais de Potássio de Domínios Poros em Tandem/genética , Canais de Potássio de Domínios Poros em Tandem/metabolismo
13.
PLoS Genet ; 16(5): e1008767, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32357156

RESUMO

Despite the importance of dendritic targeting in neural circuit assembly, the mechanisms by which it is controlled still remain incompletely understood. We previously showed that in the developing Drosophila antennal lobe, the Wnt5 protein forms a gradient that directs the ~45˚ rotation of a cluster of projection neuron (PN) dendrites, including the adjacent DA1 and VA1d dendrites. We report here that the Van Gogh (Vang) transmembrane planar cell polarity (PCP) protein is required for the rotation of the DA1/VA1d dendritic pair. Cell type-specific rescue and mosaic analyses showed that Vang functions in the olfactory receptor neurons (ORNs), suggesting a codependence of ORN axonal and PN dendritic targeting. Loss of Vang suppressed the repulsion of the VA1d dendrites by Wnt5, indicating that Wnt5 signals through Vang to direct the rotation of the DA1 and VA1d glomeruli. We observed that the Derailed (Drl)/Ryk atypical receptor tyrosine kinase is also required for the rotation of the DA1/VA1d dendritic pair. Antibody staining showed that Drl/Ryk is much more highly expressed by the DA1 dendrites than the adjacent VA1d dendrites. Mosaic and epistatic analyses showed that Drl/Ryk specifically functions in the DA1 dendrites in which it antagonizes the Wnt5-Vang repulsion and mediates the migration of the DA1 glomerulus towards Wnt5. Thus, the nascent DA1 and VA1d glomeruli appear to exhibit Drl/Ryk-dependent biphasic responses to Wnt5. Our work shows that the final patterning of the fly olfactory map is the result of an interplay between ORN axons and PN dendrites, wherein converging pre- and postsynaptic processes contribute key Wnt5 signaling components, allowing Wnt5 to orient the rotation of nascent synapses through a PCP mechanism.


Assuntos
Antenas de Artrópodes/crescimento & desenvolvimento , Dendritos/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/crescimento & desenvolvimento , Proteínas de Membrana/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Proteínas Wnt/metabolismo , Animais , Antenas de Artrópodes/metabolismo , Axônios/metabolismo , Padronização Corporal , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Membrana/genética , Neurônios Receptores Olfatórios/metabolismo , Proteínas Proto-Oncogênicas/genética , Receptores Proteína Tirosina Quinases/genética , Transdução de Sinais , Proteínas Wnt/genética
14.
Cell Mol Life Sci ; 77(21): 4289-4297, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32358623

RESUMO

Drosophila larvae need to adapt their metabolism to reach a critical body size to pupate. This process needs food resources and has to be tightly adjusted to control metamorphosis timing and adult size. Nutrients such as amino acids either directly present in the food or obtained via protein digestion play key regulatory roles in controlling metabolism and growth. Amino acids act especially on two organs, the fat body and the brain, to control larval growth, body size developmental timing and pupariation. The expression of specific amino acid transporters in fat body cells, and in the brain through specific neurons and glial cells is essential to activate downstream molecular signaling pathways in response to amino acid levels. In this review, we highlight some of these specific networks dependent on amino acid diet to control DILP levels, and by consequence larval metabolism and growth.


Assuntos
Sistemas de Transporte de Aminoácidos/metabolismo , Aminoácidos/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/crescimento & desenvolvimento , Animais , Drosophila/metabolismo , Hormônios/metabolismo , Larva/crescimento & desenvolvimento , Larva/metabolismo , Transdução de Sinais
15.
Proc Natl Acad Sci U S A ; 117(24): 13541-13551, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32467168

RESUMO

Within developing embryos, tissues flow and reorganize dramatically on timescales as short as minutes. This includes epithelial tissues, which often narrow and elongate in convergent extension movements due to anisotropies in external forces or in internal cell-generated forces. However, the mechanisms that allow or prevent tissue reorganization, especially in the presence of strongly anisotropic forces, remain unclear. We study this question in the converging and extending Drosophila germband epithelium, which displays planar-polarized myosin II and experiences anisotropic forces from neighboring tissues. We show that, in contrast to isotropic tissues, cell shape alone is not sufficient to predict the onset of rapid cell rearrangement. From theoretical considerations and vertex model simulations, we predict that in anisotropic tissues, two experimentally accessible metrics of cell patterns-the cell shape index and a cell alignment index-are required to determine whether an anisotropic tissue is in a solid-like or fluid-like state. We show that changes in cell shape and alignment over time in the Drosophila germband predict the onset of rapid cell rearrangement in both wild-type and snail twist mutant embryos, where our theoretical prediction is further improved when we also account for cell packing disorder. These findings suggest that convergent extension is associated with a transition to more fluid-like tissue behavior, which may help accommodate tissue-shape changes during rapid developmental events.


Assuntos
Forma Celular , Drosophila/crescimento & desenvolvimento , Animais , Anisotropia , Drosophila/citologia , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Epitélio/metabolismo , Miosina Tipo II/genética , Miosina Tipo II/metabolismo
16.
PLoS Genet ; 16(5): e1008815, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32453722

RESUMO

Trimethylguanosine synthase 1 (TGS1) is a conserved enzyme that mediates formation of the trimethylguanosine cap on several RNAs, including snRNAs and telomerase RNA. Previous studies have shown that TGS1 binds the Survival Motor Neuron (SMN) protein, whose deficiency causes spinal muscular atrophy (SMA). Here, we analyzed the roles of the Drosophila orthologs of the human TGS1 and SMN genes. We show that the Drosophila TGS1 protein (dTgs1) physically interacts with all subunits of the Drosophila Smn complex (Smn, Gem2, Gem3, Gem4 and Gem5), and that a human TGS1 transgene rescues the mutant phenotype caused by dTgs1 loss. We demonstrate that both dTgs1 and Smn are required for viability of retinal progenitor cells and that downregulation of these genes leads to a reduced eye size. Importantly, overexpression of dTgs1 partially rescues the eye defects caused by Smn depletion, and vice versa. These results suggest that the Drosophila eye model can be exploited for screens aimed at the identification of genes and drugs that modify the phenotypes elicited by Tgs1 and Smn deficiency. These modifiers could help to understand the molecular mechanisms underlying SMA pathogenesis and devise new therapies for this genetic disease.


Assuntos
Proteínas de Drosophila/genética , Drosophila/crescimento & desenvolvimento , Proteínas de Ligação a RNA/genética , Proteínas do Complexo SMN/genética , Animais , Regulação para Baixo , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Olho/crescimento & desenvolvimento , Olho/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Genes Letais , Tamanho do Órgão , Proteínas de Ligação a RNA/metabolismo , Proteínas do Complexo SMN/metabolismo
17.
Arch Insect Biochem Physiol ; 104(2): e21675, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32285519

RESUMO

The Drosophila inner photoreceptors R7 and R8 are responsible for color vision and their differentiation starts at the third instar larval stage. Only a handful of genes with R7 or R8-cell-specific expression are known. We performed an enhancer-trap screen using a novel piggyBac transposable element, pBGay, carrying a Gal4 sequence under the control of the P promoter to identify novel genes expressed specifically in R7 or R8 cells. From this screen, three lines were analyzed in detail: piggyBacAC109 and piggyBacAC783 are expressed in R8 cells and piggyBacAC887 is expressed in R7 cells at the third instar larval stage and pupal stages. Molecular analysis showed that the piggyBac elements were inserted into the first intron of CG14160 and CG7985 genes and the second intron of unzipped. We show the expression pattern in the developing eye imaginal disc, pupal retina as well as the adult retina. The photoreceptor-specific expression of these genes is reported for the first time and we propose that these lines are useful tools for studying the development of the visual system.


Assuntos
Elementos de DNA Transponíveis/genética , Proteínas de Drosophila/genética , Drosophila/genética , Células Fotorreceptoras de Invertebrados/metabolismo , Fatores de Transcrição/genética , Animais , Diferenciação Celular/genética , Drosophila/crescimento & desenvolvimento , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Fatores de Transcrição/metabolismo
18.
Sci Adv ; 6(13): eaaz3152, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32232161

RESUMO

In mammals, a C2H2 zinc finger (C2H2) protein, CTCF, acts as the master regulator of chromosomal architecture and of the expression of Hox gene clusters. Like mammalian CTCF, the Drosophila homolog, dCTCF, localizes to boundaries in the bithorax complex (BX-C). Here, we have determined the minimal requirements for the assembly of a functional boundary by dCTCF and two other C2H2 zinc finger proteins, Pita and Su(Hw). Although binding sites for these proteins are essential for the insulator activity of BX-C boundaries, these binding sites alone are insufficient to create a functional boundary. dCTCF cannot effectively bind to a single recognition sequence in chromatin or generate a functional insulator without the help of additional proteins. In addition, for boundary elements in BX-C at least four binding sites for dCTCF or the presence of additional DNA binding factors is required to generate a functional insulator.


Assuntos
Fator de Ligação a CCCTC/genética , Dedos de Zinco CYS2-HIS2/genética , Proteínas de Drosophila/genética , Drosophila/genética , Drosophila/metabolismo , Elementos Isolantes , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Fenótipo
19.
Mol Cell ; 78(4): 785-793.e8, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32229306

RESUMO

RNA polymerase II (RNAPII) transcription is governed by the pre-initiation complex (PIC), which contains TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIH, RNAPII, and Mediator. After initiation, RNAPII enzymes pause after transcribing less than 100 bases; precisely how RNAPII pausing is enforced and regulated remains unclear. To address specific mechanistic questions, we reconstituted human RNAPII promoter-proximal pausing in vitro, entirely with purified factors (no extracts). As expected, NELF and DSIF increased pausing, and P-TEFb promoted pause release. Unexpectedly, the PIC alone was sufficient to reconstitute pausing, suggesting RNAPII pausing is an inherent PIC function. In agreement, pausing was lost upon replacement of the TFIID complex with TATA-binding protein (TBP), and PRO-seq experiments revealed widespread disruption of RNAPII pausing upon acute depletion (t = 60 min) of TFIID subunits in human or Drosophila cells. These results establish a TFIID requirement for RNAPII pausing and suggest pause regulatory factors may function directly or indirectly through TFIID.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Regiões Promotoras Genéticas , RNA Polimerase II/genética , Fator de Transcrição TFIID/metabolismo , Transcrição Genética , Animais , Drosophila/genética , Proteínas de Drosophila/genética , Células HCT116 , Humanos , Ligação Proteica , RNA Polimerase II/metabolismo , Fator de Transcrição TFIID/genética
20.
Nat Commun ; 11(1): 1921, 2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32317641

RESUMO

Actomyosin supracellular networks emerge during development and tissue repair. These cytoskeletal structures are able to generate large scale forces that can extensively remodel epithelia driving tissue buckling, closure and extension. How supracellular networks emerge, are controlled and mechanically work still remain elusive. During Drosophila oogenesis, the egg chamber elongates along the anterior-posterior axis. Here we show that a dorsal-ventral polarized supracellular F-actin network, running around the egg chamber on the basal side of follicle cells, emerges from polarized intercellular filopodia that radiate from basal stress fibers and extend penetrating neighboring cell cortexes. Filopodia can be mechanosensitive and function as cell-cell anchoring sites. The small GTPase Cdc42 governs the formation and distribution of intercellular filopodia and stress fibers in follicle cells. Finally, our study shows that a Cdc42-dependent supracellular cytoskeletal network provides a scaffold integrating local oscillatory actomyosin contractions at the tissue scale to drive global polarized forces and tissue elongation.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Oogênese , Actinas/metabolismo , Actomiosina/metabolismo , Animais , Anisotropia , Adesão Celular , Polaridade Celular , Citoesqueleto/metabolismo , Epitélio/metabolismo , Feminino , Glutationa Transferase/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Miosina Tipo II/metabolismo , Optogenética , Pseudópodes/metabolismo , Interferência de RNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA