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1.
Biochem J ; 478(20): 3791-3805, 2021 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-34709374

RESUMO

Meiosis facilitates diversity across individuals and serves as a major driver of evolution. However, understanding how meiosis begins is complicated by fundamental differences that exist between sexes and species. Fundamental meiotic research is further hampered by a current lack of human meiotic cells lines. Consequently, much of what we know relies on data from model organisms. However, contextualising findings from yeast, worms, flies and mice can be challenging, due to marked differences in both nomenclature and the relative timing of meiosis. In this review, we set out to combine current knowledge of signalling and transcriptional pathways that control meiosis initiation across the sexes in a variety of organisms. Furthermore, we highlight the emerging links between meiosis initiation and oncogenesis, which might explain the frequent re-expression of normally silent meiotic genes in a variety of human cancers.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Meiose , Oogênese/genética , Espermatogênese/genética , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/genética , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/metabolismo , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinogênese/patologia , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Feminino , Humanos , Masculino , Camundongos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Fatores Sexuais , Transdução de Sinais , Fatores de Tempo , Xenopus laevis/genética , Xenopus laevis/crescimento & desenvolvimento , Xenopus laevis/metabolismo
2.
Int J Mol Sci ; 22(19)2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34638607

RESUMO

Asymmetric cell division (ACD) of neural stem cells and progenitors not only renews the stem cell population but also ensures the normal development of the nervous system, producing various types of neurons with different shapes and functions in the brain. One major mechanism to achieve ACD is the asymmetric localization and uneven segregation of intracellular proteins and organelles into sibling cells. Recent studies have demonstrated that liquid-liquid phase separation (LLPS) provides a potential mechanism for the formation of membrane-less biomolecular condensates that are asymmetrically distributed on limited membrane regions. Moreover, mechanical forces have emerged as pivotal regulators of asymmetric neural stem cell division by generating sibling cell size asymmetry. In this review, we will summarize recent discoveries of ACD mechanisms driven by LLPS and mechanical forces.


Assuntos
Divisão Celular Assimétrica/fisiologia , Células-Tronco Neurais/citologia , Células-Tronco Neurais/fisiologia , Animais , Fenômenos Biomecânicos , Divisão Celular/fisiologia , Polaridade Celular/fisiologia , Tamanho Celular , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/citologia , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/fisiologia , Modelos Neurológicos , Miosinas/fisiologia , Neurogênese/fisiologia , Organelas/fisiologia
3.
Elife ; 102021 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-34553686

RESUMO

The gut is the primary interface between an animal and food, but how it adapts to qualitative dietary variation is poorly defined. We find that the Drosophila midgut plastically resizes following changes in dietary composition. A panel of nutrients collectively promote gut growth, which sugar opposes. Diet influences absolute and relative levels of enterocyte loss and stem cell proliferation, which together determine cell numbers. Diet also influences enterocyte size. A high sugar diet inhibits translation and uncouples intestinal stem cell proliferation from expression of niche-derived signals, but, surprisingly, rescuing these effects genetically was not sufficient to modify diet's impact on midgut size. However, when stem cell proliferation was deficient, diet's impact on enterocyte size was enhanced, and reducing enterocyte-autonomous TOR signaling was sufficient to attenuate diet-dependent midgut resizing. These data clarify the complex relationships between nutrition, epithelial dynamics, and cell size, and reveal a new mode of plastic, diet-dependent organ resizing.


Assuntos
Dieta , Drosophila melanogaster/crescimento & desenvolvimento , Trato Gastrointestinal/crescimento & desenvolvimento , Animais , Animais Geneticamente Modificados , Proliferação de Células , Drosophila melanogaster/fisiologia , Enterócitos/citologia , Feminino , Trato Gastrointestinal/citologia , Trato Gastrointestinal/fisiologia , Masculino , Nicho de Células-Tronco
4.
Elife ; 102021 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-34590579

RESUMO

Production of proliferative follicle cells (FCs) and quiescent escort cells (ECs) by follicle stem cells (FSCs) in adult Drosophila ovaries is regulated by niche signals from anterior (cap cells, ECs) and posterior (polar FCs) sources. Here we show that ECs, FSCs, and FCs develop from common pupal precursors, with different fates acquired by progressive separation of cells along the AP axis and a graded decline in anterior cell proliferation. ECs, FSCs, and most FCs derive from intermingled cell (IC) precursors interspersed with germline cells. Precursors also accumulate posterior to ICs before engulfing a naked germline cyst projected out of the germarium to form the first egg chamber and posterior polar FC signaling center. Thus, stem and niche cells develop in appropriate numbers and spatial organization through regulated proliferative expansion together with progressive establishment of spatial signaling cues that guide adult cell behavior, rather than through rigid early specification events.


Assuntos
Drosophila melanogaster/crescimento & desenvolvimento , Ovário/crescimento & desenvolvimento , Células-Tronco/metabolismo , Animais , Feminino , Pupa/crescimento & desenvolvimento
5.
Nat Commun ; 12(1): 5488, 2021 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-34531401

RESUMO

Specialised ribonucleoprotein (RNP) granules are a hallmark of polarized cells, like neurons and germ cells. Among their main functions is the spatial and temporal modulation of the activity of specific mRNA transcripts that allow specification of primary embryonic axes. While RNPs composition and role are well established, their regulation is poorly defined. Here, we demonstrate that Hecw, a newly identified Drosophila ubiquitin ligase, is a key modulator of RNPs in oogenesis and neurons. Hecw depletion leads to the formation of enlarged granules that transition from a liquid to a gel-like state. Loss of Hecw activity results in defective oogenesis, premature aging and climbing defects associated with neuronal loss. At the molecular level, reduced ubiquitination of the Fmrp impairs its translational repressor activity, resulting in altered Orb expression in nurse cells and Profilin in neurons.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Regulação da Expressão Gênica no Desenvolvimento , Neurogênese/genética , Oogênese/genética , Ribonucleoproteínas/genética , Ubiquitina-Proteína Ligases/genética , Animais , Grânulos Citoplasmáticos/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citologia , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Embrião não Mamífero , Proteína do X Frágil de Retardo Mental/genética , Proteína do X Frágil de Retardo Mental/metabolismo , Homeostase/genética , Longevidade/genética , Neurônios/citologia , Neurônios/metabolismo , Oócitos/citologia , Oócitos/metabolismo , Transição de Fase , Profilinas/genética , Profilinas/metabolismo , Biossíntese de Proteínas , Processamento de Proteína Pós-Traducional , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Ribonucleoproteínas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
8.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34544850

RESUMO

In order to respond to infection, hosts must distinguish pathogens from their own tissues. This allows for the precise targeting of immune responses against pathogens and also ensures self-tolerance, the ability of the host to protect self tissues from immune damage. One way to maintain self-tolerance is to evolve a self signal and suppress any immune response directed at tissues that carry this signal. Here, we characterize the Drosophila tuSz 1 mutant strain, which mounts an aberrant immune response against its own fat body. We demonstrate that this autoimmunity is the result of two mutations: 1) a mutation in the GCS1 gene that disrupts N-glycosylation of extracellular matrix proteins covering the fat body, and 2) a mutation in the Drosophila Janus Kinase ortholog that causes precocious activation of hemocytes. Our data indicate that N-glycans attached to extracellular matrix proteins serve as a self signal and that activated hemocytes attack tissues lacking this signal. The simplicity of this invertebrate self-recognition system and the ubiquity of its constituent parts suggests it may have functional homologs across animals.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/imunologia , Proteínas da Matriz Extracelular/metabolismo , Tolerância Imunológica/imunologia , Janus Quinases/metabolismo , Mutação , Tolerância a Antígenos Próprios , Animais , Proteínas de Drosophila/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Proteínas da Matriz Extracelular/genética , Glicosilação , Hemócitos , Janus Quinases/genética
9.
PLoS Biol ; 19(8): e3001367, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34379617

RESUMO

Damage in the nervous system induces a stereotypical response that is mediated by glial cells. Here, we use the eye disc of Drosophila melanogaster as a model to explore the mechanisms involved in promoting glial cell response after neuronal cell death induction. We demonstrate that these cells rapidly respond to neuronal apoptosis by increasing in number and undergoing morphological changes, which will ultimately grant them phagocytic abilities. We found that this glial response is controlled by the activity of Decapentaplegic (Dpp) and Hedgehog (Hh) signalling pathways. These pathways are activated after cell death induction, and their functions are necessary to induce glial cell proliferation and migration to the eye discs. The latter of these 2 processes depend on the function of the c-Jun N-terminal kinase (JNK) pathway, which is activated by Dpp signalling. We also present evidence that a similar mechanism controls glial response upon apoptosis induction in the leg discs, suggesting that our results uncover a mechanism that might be involved in controlling glial cells response to neuronal cell death in different regions of the peripheral nervous system (PNS).


Assuntos
Olho Composto de Artrópodes/crescimento & desenvolvimento , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/crescimento & desenvolvimento , Proteínas Hedgehog/fisiologia , Neuroglia/fisiologia , Animais , Apoptose , Movimento Celular , Olho Composto de Artrópodes/citologia , Drosophila melanogaster/citologia , Sistema de Sinalização das MAP Quinases
10.
PLoS Pathog ; 17(8): e1009326, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34339477

RESUMO

Metabolic pathways are now considered as intrinsic virulence attributes of pathogenic bacteria and thus represent potential targets for antibacterial strategies. Here we focused on the role of the pentose phosphate pathway (PPP) and its connections with other metabolic pathways in the pathophysiology of Francisella novicida. The involvement of the PPP in the intracellular life cycle of Francisella was first demonstrated by studying PPP inactivating mutants. Indeed, we observed that inactivation of the tktA, rpiA or rpe genes severely impaired intramacrophage multiplication during the first 24 hours. However, time-lapse video microscopy demonstrated that rpiA and rpe mutants were able to resume late intracellular multiplication. To better understand the links between PPP and other metabolic networks in the bacterium, we also performed an extensive proteo-metabolomic analysis of these mutants. We show that the PPP constitutes a major bacterial metabolic hub with multiple connections to glycolysis, the tricarboxylic acid cycle and other pathways, such as fatty acid degradation and sulfur metabolism. Altogether our study highlights how PPP plays a key role in the pathogenesis and growth of Francisella in its intracellular niche.


Assuntos
Proteínas de Bactérias/metabolismo , Drosophila melanogaster/metabolismo , Francisella/patogenicidade , Infecções por Bactérias Gram-Negativas/microbiologia , Metaboloma , Via de Pentose Fosfato , Proteoma , Animais , Proteínas de Bactérias/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/microbiologia , Francisella/metabolismo , Regulação Bacteriana da Expressão Gênica , Glicólise , Macrófagos/metabolismo , Macrófagos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mutação
11.
PLoS One ; 16(8): e0255066, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34351964

RESUMO

Natural background radiation is a permanent multicomponent factor. It has an influence on biological organisms, but effects of its deprivation still remain unclear. The aim of our work was to study for the first time responses of D. melanogaster to conditions of the Deep Underground Low-Background Laboratory DULB-4900 (BNO, INR, RAS, Russia) at the transcriptome level by RNA-seq profiling. Overall 77 transcripts demonstrated differential abundance between flies exposed to low and natural background radiation. Enriched biological process functional categories were established for all genes with differential expression. The results showed down-regulation of primary metabolic processes and up-regulation of both the immune system process and the response to stimuli. The comparative analysis of our data and publicly available transcriptome data on D. melanogaster exposed to low and high doses of ionizing radiation did not reveal common DEGs in them. We hypothesize that the observed changes in gene expression can be explained by the influence of the underground conditions in DULB-4900, in particular, by the lack of stimuli. Thus, our study challenges the validity of the LNT model for the region of background radiation doses below a certain level (~16.4 nGy h-1) and the presence of a dose threshold for D. melanogaster.


Assuntos
Radiação de Fundo , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/genética , Perfilação da Expressão Gênica , Laboratórios , Animais , Regulação da Expressão Gênica no Desenvolvimento , Ontologia Genética , RNA-Seq , Federação Russa
12.
PLoS Comput Biol ; 17(8): e1009245, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34343167

RESUMO

Morphogen gradients are crucial for the development of organisms. The biochemical properties of many morphogens prevent their extracellular free diffusion, indicating the need of an active mechanism for transport. The involvement of filopodial structures (cytonemes) has been proposed for morphogen signaling. Here, we describe an in silico model based on the main general features of cytoneme-meditated gradient formation and its implementation into Cytomorph, an open software tool. We have tested the spatial and temporal adaptability of our model quantifying Hedgehog (Hh) gradient formation in two Drosophila tissues. Cytomorph is able to reproduce the gradient and explain the different scaling between the two epithelia. After experimental validation, we studied the predicted impact of a range of features such as length, size, density, dynamics and contact behavior of cytonemes on Hh morphogen distribution. Our results illustrate Cytomorph as an adaptive tool to test different morphogen gradients and to generate hypotheses that are difficult to study experimentally.


Assuntos
Modelos Biológicos , Morfogênese/fisiologia , Animais , Animais Geneticamente Modificados , Padronização Corporal/fisiologia , Biologia Computacional , Simulação por Computador , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Proteínas Hedgehog/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Pseudópodes/metabolismo , Transdução de Sinais , Software , Asas de Animais/crescimento & desenvolvimento , Asas de Animais/metabolismo
13.
Sci Rep ; 11(1): 16434, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34385533

RESUMO

In holometabolous insects like Drosophila melanogaster, critical size is an important time point during larval life, for irreversible commitment to metamorphosis. Here, we studied the impact of restricted growth duration in terms of selection for faster pre-adult development in Drosophila melanogaster populations which resulted in the evolution of reduced critical size on adult life history traits. Selection for faster pre-adult development resulted in biochemical adaptation in larval physiology with no compromise in major biomolecules at critical size time point. The flies from the selected populations seem to not only commit to metamorphosis on the attainment of critical size but also seem to channelize resources to reproduction as indicated by similar life-time fecundity of CS and NS flies from selected populations, while the Control CS flies significantly lower life-time fecundity compared to Control NS flies. The flies from selected populations seem to achieve longevity comparable to control flies despite being significantly smaller in size-thus resource constrained due to faster pre-adult development.


Assuntos
Adaptação Fisiológica , Drosophila melanogaster/fisiologia , Longevidade , Animais , Drosophila melanogaster/crescimento & desenvolvimento , Feminino , Fertilidade , Larva/crescimento & desenvolvimento , Masculino , Metamorfose Biológica
14.
PLoS Pathog ; 17(8): e1009859, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34383852

RESUMO

Wolbachia is a group of intracellular symbiotic bacteria that widely infect arthropods and nematodes. Wolbachia infection can regulate host reproduction with the most common phenotype in insects being cytoplasmic incompatibility (CI), which results in embryonic lethality when uninfected eggs fertilized with sperms from infected males. This suggests that CI-induced defects are mainly in paternal side. However, whether Wolbachia-induced metabolic changes play a role in the mechanism of paternal-linked defects in embryonic development is not known. In the current study, we first use untargeted metabolomics method with LC-MS to explore how Wolbachia infection influences the metabolite profiling of the insect hosts. The untargeted metabolomics revealed 414 potential differential metabolites between Wolbachia-infected and uninfected 1-day-old (1d) male flies. Most of the differential metabolites were significantly up-regulated due to Wolbachia infection. Thirty-four metabolic pathways such as carbohydrate, lipid and amino acid, and vitamin and cofactor metabolism were affected by Wolbachia infection. Then, we applied targeted metabolomics analysis with GC-MS and showed that Wolbachia infection resulted in an increased energy expenditure of the host by regulating glycometabolism and fatty acid catabolism, which was compensated by increased food uptake. Furthermore, overexpressing two acyl-CoA catabolism related genes, Dbi (coding for diazepam-binding inhibitor) or Mcad (coding for medium-chain acyl-CoA dehydrogenase), ubiquitously or specially in testes caused significantly decreased paternal-effect egg hatch rate. Oxidative stress and abnormal mitochondria induced by Wolbachia infection disrupted the formation of sperm nebenkern. These findings provide new insights into mechanisms of Wolbachia-induced paternal defects from metabolic phenotypes.


Assuntos
Infecções Bacterianas/complicações , Drosophila melanogaster/metabolismo , Infertilidade Masculina/patologia , Metaboloma , Fenótipo , Reprodução , Wolbachia/fisiologia , Animais , Infecções Bacterianas/metabolismo , Infecções Bacterianas/microbiologia , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/microbiologia , Feminino , Infertilidade Masculina/etiologia , Infertilidade Masculina/metabolismo , Masculino
15.
Nat Commun ; 12(1): 5178, 2021 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-34462441

RESUMO

Animals maintain metabolic homeostasis by modulating the activity of specialized organs that adjust internal metabolism to external conditions. However, the hormonal signals coordinating these functions are incompletely characterized. Here we show that six neurosecretory cells in the Drosophila central nervous system respond to circulating nutrient levels by releasing Capa hormones, homologs of mammalian neuromedin U, which activate the Capa receptor (CapaR) in peripheral tissues to control energy homeostasis. Loss of Capa/CapaR signaling causes intestinal hypomotility and impaired nutrient absorption, which gradually deplete internal nutrient stores and reduce organismal lifespan. Conversely, increased Capa/CapaR activity increases fluid and waste excretion. Furthermore, Capa/CapaR inhibits the release of glucagon-like adipokinetic hormone from the corpora cardiaca, which restricts energy mobilization from adipose tissue to avoid harmful hyperglycemia. Our results suggest that the Capa/CapaR circuit occupies a central node in a homeostatic program that facilitates the digestion and absorption of nutrients and regulates systemic energy balance.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Neuropeptídeos/metabolismo , Nutrientes/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Metabolismo Energético , Feminino , Homeostase , Hormônios de Inseto/metabolismo , Longevidade , Masculino , Neuropeptídeos/genética , Oligopeptídeos/metabolismo , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/metabolismo , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais
16.
J Insect Physiol ; 134: 104294, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34389412

RESUMO

In insects, some sterols are essential not only for cell membrane homeostasis, but for biosynthesis of the steroid hormone ecdysone. Dietary sterols are required for insect development because insects cannot synthesize sterols de novo. Therefore, sterol-like compounds that can compete with essential sterols are good candidates for insect growth regulators. In this study, we investigated the effects of the plant-derived triterpenoids, cucurbitacin B and E (CucB and CucE) on the development of the fruit fly, Drosophila melanogaster. To reduce the effects of supply with an excess of sterols contained in food, we reared D. melanogaster larvae on low sterol food (LSF) with or without cucurbitacins. Most larvae raised on LSF without supplementation or with CucE died at the second or third larval instar (L2 or L3) stages, whereas CucB-administered larvae mostly died without molting. The developmental arrest caused by CucB was partially rescued by ecdysone supplementation. Furthermore, we examined the effects of CucB on larval-prepupal transition by transferring larvae from LSF supplemented with cholesterol to that with CucB just after the L2/L3 molt. L3 larvae raised on LSF with CucB failed to pupariate, with a remarkable developmental delay. Ecdysone supplementation rescued the developmental delay but did not rescue the pupariation defect. Furthermore, we cultured the steroidogenic organ, the prothoracic gland (PG) of the silkworm Bombyx mori, with or without cucurbitacin. Ecdysone production in the PG was reduced by incubation with CucB, but not with CucE. These results suggest that CucB acts not only as an antagonist of the ecdysone receptor as previously reported, but also acts as an inhibitor of ecdysone biosynthesis.


Assuntos
Drosophila melanogaster , Ecdisona , Triterpenos/farmacologia , Animais , Bombyx/efeitos dos fármacos , Bombyx/metabolismo , Proteínas de Drosophila/efeitos dos fármacos , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Ecdisona/antagonistas & inibidores , Ecdisona/biossíntese , Regulação da Expressão Gênica no Desenvolvimento , Hormônios Juvenis/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/metabolismo , Metamorfose Biológica/efeitos dos fármacos , Muda/efeitos dos fármacos , Técnicas de Cultura de Órgãos , Extratos Vegetais/farmacologia , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Pupa/metabolismo
17.
Am J Hum Genet ; 108(9): 1669-1691, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34314705

RESUMO

Transportin-2 (TNPO2) mediates multiple pathways including non-classical nucleocytoplasmic shuttling of >60 cargoes, such as developmental and neuronal proteins. We identified 15 individuals carrying de novo coding variants in TNPO2 who presented with global developmental delay (GDD), dysmorphic features, ophthalmologic abnormalities, and neurological features. To assess the nature of these variants, functional studies were performed in Drosophila. We found that fly dTnpo (orthologous to TNPO2) is expressed in a subset of neurons. dTnpo is critical for neuronal maintenance and function as downregulating dTnpo in mature neurons using RNAi disrupts neuronal activity and survival. Altering the activity and expression of dTnpo using mutant alleles or RNAi causes developmental defects, including eye and wing deformities and lethality. These effects are dosage dependent as more severe phenotypes are associated with stronger dTnpo loss. Interestingly, similar phenotypes are observed with dTnpo upregulation and ectopic expression of TNPO2, showing that loss and gain of Transportin activity causes developmental defects. Further, proband-associated variants can cause more or less severe developmental abnormalities compared to wild-type TNPO2 when ectopically expressed. The impact of the variants tested seems to correlate with their position within the protein. Specifically, those that fall within the RAN binding domain cause more severe toxicity and those in the acidic loop are less toxic. Variants within the cargo binding domain show tissue-dependent effects. In summary, dTnpo is an essential gene in flies during development and in neurons. Further, proband-associated de novo variants within TNPO2 disrupt the function of the encoded protein. Hence, TNPO2 variants are causative for neurodevelopmental abnormalities.


Assuntos
Deficiências do Desenvolvimento/genética , Proteínas de Drosophila/genética , Oftalmopatias Hereditárias/genética , Deficiência Intelectual/genética , Carioferinas/genética , Anormalidades Musculoesqueléticas/genética , beta Carioferinas/genética , Proteína ran de Ligação ao GTP/genética , Alelos , Sequência de Aminoácidos , Animais , Deficiências do Desenvolvimento/metabolismo , Deficiências do Desenvolvimento/patologia , Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Oftalmopatias Hereditárias/metabolismo , Oftalmopatias Hereditárias/patologia , Feminino , Dosagem de Genes , Regulação da Expressão Gênica no Desenvolvimento , Genoma Humano , Humanos , Lactente , Recém-Nascido , Deficiência Intelectual/metabolismo , Deficiência Intelectual/patologia , Carioferinas/antagonistas & inibidores , Carioferinas/metabolismo , Masculino , Anormalidades Musculoesqueléticas/metabolismo , Anormalidades Musculoesqueléticas/patologia , Mutação , Neurônios/metabolismo , Neurônios/patologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Sequenciamento Completo do Genoma , beta Carioferinas/metabolismo , Proteína ran de Ligação ao GTP/metabolismo
18.
Dev Cell ; 56(14): 2043-2058.e7, 2021 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-34216545

RESUMO

Aneuploidy, an unbalanced number of chromosomes, is highly deleterious at the cellular level and leads to senescence, a stress-induced response characterized by permanent cell-cycle arrest and a well-defined associated secretory phenotype. Here, we use a Drosophila epithelial model to delineate the pathway that leads to the induction of senescence as a consequence of the acquisition of an aneuploid karyotype. Whereas aneuploidy induces, as a result of gene dosage imbalance, proteotoxic stress and activation of the major protein quality control mechanisms, near-saturation functioning of autophagy leads to compromised mitophagy, accumulation of dysfunctional mitochondria, and the production of radical oxygen species (ROS). We uncovered a role of c-Jun N-terminal kinase (JNK) in driving senescence as a consequence of dysfunctional mitochondria and ROS. We show that activation of the major protein quality control mechanisms and mitophagy dampens the deleterious effects of aneuploidy, and we identify a role of senescence in proteostasis and compensatory proliferation for tissue repair.


Assuntos
Aneuploidia , Senescência Celular , Drosophila melanogaster/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Mitocôndrias/patologia , Mitofagia , Proteostase , Animais , Autofagia , Instabilidade Cromossômica , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Feminino , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Masculino , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio
19.
Nucleic Acids Res ; 49(15): 8866-8885, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34329466

RESUMO

A key regulatory process during Drosophila development is the localized suppression of the hunchback mRNA translation at the posterior, which gives rise to a hunchback gradient governing the formation of the anterior-posterior body axis. This suppression is achieved by a concerted action of Brain Tumour (Brat), Pumilio (Pum) and Nanos. Each protein is necessary for proper Drosophila development. The RNA contacts have been elucidated for the proteins individually in several atomic-resolution structures. However, the interplay of all three proteins during RNA suppression remains a long-standing open question. Here, we characterize the quaternary complex of the RNA-binding domains of Brat, Pum and Nanos with hunchback mRNA by combining NMR spectroscopy, SANS/SAXS, XL/MS with MD simulations and ITC assays. The quaternary hunchback mRNA suppression complex comprising the RNA binding domains is flexible with unoccupied nucleotides functioning as a flexible linker between the Brat and Pum-Nanos moieties of the complex. Moreover, the presence of the Pum-HD/Nanos-ZnF complex has no effect on the equilibrium RNA binding affinity of the Brat RNA binding domain. This is in accordance with previous studies, which showed that Brat can suppress mRNA independently and is distributed uniformly throughout the embryo.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/genética , Desenvolvimento Embrionário/genética , Proteínas de Ligação a RNA/genética , Fatores de Transcrição/genética , Animais , Padronização Corporal/genética , Proteínas de Ligação a DNA/ultraestrutura , Proteínas de Drosophila/ultraestrutura , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Complexos Multiproteicos/genética , Complexos Multiproteicos/ultraestrutura , Ressonância Magnética Nuclear Biomolecular , Estrutura Quaternária de Proteína , Proteínas com Motivo de Reconhecimento de RNA/genética , Proteínas com Motivo de Reconhecimento de RNA/ultraestrutura , Proteínas de Ligação a RNA/ultraestrutura , Espalhamento a Baixo Ângulo , Fatores de Transcrição/ultraestrutura , Difração de Raios X
20.
Development ; 148(16)2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34322714

RESUMO

Dendrite shape impacts functional connectivity and is mediated by organization and dynamics of cytoskeletal fibers. Identifying the molecular factors that regulate dendritic cytoskeletal architecture is therefore important in understanding the mechanistic links between cytoskeletal organization and neuronal function. We identified Formin 3 (Form3) as an essential regulator of cytoskeletal architecture in nociceptive sensory neurons in Drosophila larvae. Time course analyses reveal that Form3 is cell-autonomously required to promote dendritic arbor complexity. We show that form3 is required for the maintenance of a population of stable dendritic microtubules (MTs), and mutants exhibit defects in the localization of dendritic mitochondria, satellite Golgi, and the TRPA channel Painless. Form3 directly interacts with MTs via FH1-FH2 domains. Mutations in human inverted formin 2 (INF2; ortholog of form3) have been causally linked to Charcot-Marie-Tooth (CMT) disease. CMT sensory neuropathies lead to impaired peripheral sensitivity. Defects in form3 function in nociceptive neurons result in severe impairment of noxious heat-evoked behaviors. Expression of the INF2 FH1-FH2 domains partially recovers form3 defects in MTs and nocifensive behavior, suggesting conserved functions, thereby providing putative mechanistic insights into potential etiologies of CMT sensory neuropathies.


Assuntos
Dendritos/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Forminas/metabolismo , Microtúbulos/metabolismo , Plasticidade Neuronal/genética , Nociceptividade , Actinas/metabolismo , Animais , Animais Geneticamente Modificados , Comportamento Animal , Citoesqueleto/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Forminas/genética , Humanos , Mutação , Nociceptores/metabolismo , Transgenes
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