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1.
Nat Commun ; 11(1): 4782, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32963223

RESUMO

Polycomb and Trithorax group proteins maintain stable epigenetic memory of gene expression states for some genes, but many targets show highly dynamic regulation. Here we combine experiment and theory to examine the mechanistic basis of these different modes of regulation. We present a mathematical model comprising a Polycomb/Trithorax response element (PRE/TRE) coupled to a promoter and including Drosophila developmental timing. The model accurately recapitulates published studies of PRE/TRE mediated epigenetic memory of both silencing and activation. With minimal parameter changes, the same model can also recapitulate experimental data for a different PRE/TRE that allows dynamic regulation of its target gene. The model predicts that both cell cycle length and PRE/TRE identity are critical for determining whether the system gives stable memory or dynamic regulation. Our work provides a simple unifying framework for a rich repertoire of PRE/TRE functions, and thus provides insights into  genome-wide Polycomb/Trithorax regulation.


Assuntos
Proteínas Cromossômicas não Histona/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Epigenômica , Regulação da Expressão Gênica no Desenvolvimento/genética , Modelos Teóricos , Complexo Repressor Polycomb 1/genética , Animais , Divisão Celular , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Epigênese Genética , Feminino , Inativação Gênica , Complexo Repressor Polycomb 1/metabolismo , Proteínas do Grupo Polycomb/metabolismo , Regiões Promotoras Genéticas , Elementos de Resposta
2.
Nat Commun ; 11(1): 4477, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901019

RESUMO

Individual cells detach from cohesive ensembles during development and can inappropriately separate in disease. Although much is known about how cells separate from epithelia, it remains unclear how cells disperse from clusters lacking apical-basal polarity, a hallmark of advanced epithelial cancers. Here, using live imaging of the developmental migration program of Drosophila primordial germ cells (PGCs), we show that cluster dispersal is accomplished by stabilizing and orienting migratory forces. PGCs utilize a G protein coupled receptor (GPCR), Tre1, to guide front-back migratory polarity radially from the cluster toward the endoderm. Posteriorly positioned myosin-dependent contractile forces pull on cell-cell contacts until cells release. Tre1 mutant cells migrate randomly with transient enrichment of the force machinery but fail to separate, indicating a temporal contractile force threshold for detachment. E-cadherin is retained on the cell surface during cell separation and augmenting cell-cell adhesion does not impede detachment. Notably, coordinated migration improves cluster dispersal efficiency by stabilizing cell-cell interfaces and facilitating symmetric pulling. We demonstrate that guidance of inherent migratory forces is sufficient to disperse cell clusters under physiological settings and present a paradigm for how such events could occur across development and disease.


Assuntos
Drosophila melanogaster/embriologia , Células Germinativas Embrionárias/fisiologia , Animais , Animais Geneticamente Modificados , Fenômenos Biomecânicos , Padronização Corporal/fisiologia , Caderinas/metabolismo , Adesão Celular/fisiologia , Movimento Celular/fisiologia , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citologia , Drosophila melanogaster/fisiologia , Células Germinativas Embrionárias/citologia , Microscopia de Fluorescência por Excitação Multifotônica , Miosina Tipo II/metabolismo , Transdução de Sinais , Análise de Célula Única , Proteínas rho de Ligação ao GTP/metabolismo
3.
Nat Commun ; 11(1): 4653, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32938923

RESUMO

Cancer cells demand excess nutrients to support their proliferation, but how tumours exploit extracellular amino acids during systemic metabolic perturbations remain incompletely understood. Here, we use a Drosophila model of high-sugar diet (HSD)-enhanced tumourigenesis to uncover a systemic host-tumour metabolic circuit that supports tumour growth. We demonstrate coordinate induction of systemic muscle wasting with tumour-autonomous Yorkie-mediated SLC36-family amino acid transporter expression as a proline-scavenging programme to drive tumourigenesis. We identify Indole-3-propionic acid as an optimal amino acid derivative to rationally target the proline-dependency of tumour growth. Insights from this whole-animal Drosophila model provide a powerful approach towards the identification and therapeutic exploitation of the amino acid vulnerabilities of tumourigenesis in the context of a perturbed systemic metabolic network.


Assuntos
Açúcares da Dieta/efeitos adversos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiopatologia , Neoplasias Experimentais/fisiopatologia , Prolina/metabolismo , Sistemas de Transporte de Aminoácidos/genética , Sistemas de Transporte de Aminoácidos/metabolismo , Animais , Animais Geneticamente Modificados , Carcinogênese , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Perfilação da Expressão Gênica , Hemolinfa/efeitos dos fármacos , Hemolinfa/metabolismo , Larva , Debilidade Muscular/induzido quimicamente , Debilidade Muscular/patologia , Atrofia Muscular/induzido quimicamente , Atrofia Muscular/patologia , Neoplasias Experimentais/etiologia , Proteínas Nucleares/genética , Receptores Proteína Tirosina Quinases/metabolismo , Transativadores/genética , Proteínas ras/genética
4.
Nat Commun ; 11(1): 4677, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32938929

RESUMO

The Integrated Stress Response (ISR) helps metazoan cells adapt to cellular stress by limiting the availability of initiator methionyl-tRNA for translation. Such limiting conditions paradoxically stimulate the translation of ATF4 mRNA through a regulatory 5' leader sequence with multiple upstream Open Reading Frames (uORFs), thereby activating stress-responsive gene expression. Here, we report the identification of two critical regulators of such ATF4 induction, the noncanonical initiation factors eIF2D and DENR. Loss of eIF2D and DENR in Drosophila results in increased vulnerability to amino acid deprivation, susceptibility to retinal degeneration caused by endoplasmic reticulum (ER) stress, and developmental defects similar to ATF4 mutants. eIF2D requires its RNA-binding motif for regulation of 5' leader-mediated ATF4 translation. Consistently, eIF2D and DENR deficient human cells show impaired ATF4 protein induction in response to ER stress. Altogether, our findings indicate that eIF2D and DENR are critical mediators of ATF4 translational induction and stress responses in vivo.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Estresse do Retículo Endoplasmático/genética , Fatores de Iniciação em Eucariotos/genética , Biossíntese de Proteínas , Fatores de Transcrição/genética , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Animais Geneticamente Modificados , Sítios de Ligação , Linhagem Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Fator de Iniciação 2 em Eucariotos/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , Humanos , Mutação , Fases de Leitura Aberta , Interferência de RNA , Degeneração Retiniana/genética , Fatores de Transcrição/metabolismo
5.
PLoS Biol ; 18(8): e3000548, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32745077

RESUMO

Sleep is vital for survival. Yet under environmentally challenging conditions, such as starvation, animals suppress their need for sleep. Interestingly, starvation-induced sleep loss does not evoke a subsequent sleep rebound. Little is known about how starvation-induced sleep deprivation differs from other types of sleep loss, or why some sleep functions become dispensable during starvation. Here, we demonstrate that down-regulation of the secreted cytokine unpaired 2 (upd2) in Drosophila flies may mimic a starved-like state. We used a genetic knockdown strategy to investigate the consequences of upd2 on visual attention and sleep in otherwise well-fed flies, thereby sidestepping the negative side effects of undernourishment. We find that knockdown of upd2 in the fat body (FB) is sufficient to suppress sleep and promote feeding-related behaviors while also improving selective visual attention. Furthermore, we show that this peripheral signal is integrated in the fly brain via insulin-expressing cells. Together, these findings identify a role for peripheral tissue-to-brain interactions in the simultaneous regulation of sleep quality and attention, to potentially promote adaptive behaviors necessary for survival in hungry animals.


Assuntos
Atenção/fisiologia , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Comportamento Alimentar/fisiologia , Inanição/genética , Percepção Visual/fisiologia , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Proteínas de Drosophila/deficiência , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Corpo Adiposo/metabolismo , Feminino , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Insulina/genética , Insulina/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Neuropeptídeos/genética , Neuropeptídeos/metabolismo , Transdução de Sinais , Sono/fisiologia , Privação do Sono/genética , Privação do Sono/metabolismo , Inanição/metabolismo
6.
PLoS Biol ; 18(8): e3000762, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32760088

RESUMO

Centrosomes, the main microtubule organizing centers (MTOCs) of metazoan cells, contain an older "mother" and a younger "daughter" centriole. Stem cells either inherit the mother or daughter-centriole-containing centrosome, providing a possible mechanism for biased delivery of cell fate determinants. However, the mechanisms regulating centrosome asymmetry and biased centrosome segregation are unclear. Using 3D-structured illumination microscopy (3D-SIM) and live-cell imaging, we show in fly neural stem cells (neuroblasts) that the mitotic kinase Polo and its centriolar protein substrate Centrobin (Cnb) accumulate on the daughter centriole during mitosis, thereby generating molecularly distinct mother and daughter centrioles before interphase. Cnb's asymmetric localization, potentially involving a direct relocalization mechanism, is regulated by Polo-mediated phosphorylation, whereas Polo's daughter centriole enrichment requires both Wdr62 and Cnb. Based on optogenetic protein mislocalization experiments, we propose that the establishment of centriole asymmetry in mitosis primes biased interphase MTOC activity, necessary for correct spindle orientation.


Assuntos
Proteínas de Ciclo Celular/genética , Centríolos/metabolismo , Centrossomo/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Mitose , Proteínas Serina-Treonina Quinases/genética , Animais , Animais Geneticamente Modificados , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Ciclo Celular/metabolismo , Centríolos/ultraestrutura , Centrossomo/ultraestrutura , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citologia , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Embrião não Mamífero , Regulação da Expressão Gênica no Desenvolvimento , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Interfase , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Optogenética/métodos , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais
7.
Nat Commun ; 11(1): 4263, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32848132

RESUMO

Eukaryotic DNA replication initiation relies on the origin recognition complex (ORC), a DNA-binding ATPase that loads the Mcm2-7 replicative helicase onto replication origins. Here, we report cryo-electron microscopy (cryo-EM) structures of DNA-bound Drosophila ORC with and without the co-loader Cdc6. These structures reveal that Orc1 and Orc4 constitute the primary DNA binding site in the ORC ring and cooperate with the winged-helix domains to stabilize DNA bending. A loop region near the catalytic Walker B motif of Orc1 directly contacts DNA, allosterically coupling DNA binding to ORC's ATPase site. Correlating structural and biochemical data show that DNA sequence modulates DNA binding and remodeling by ORC, and that DNA bending promotes Mcm2-7 loading in vitro. Together, these findings explain the distinct DNA sequence-dependencies of metazoan and S. cerevisiae initiators in origin recognition and support a model in which DNA geometry and bendability contribute to Mcm2-7 loading site selection in metazoans.


Assuntos
Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Proteínas de Drosophila/química , Proteínas de Drosophila/metabolismo , Complexo de Reconhecimento de Origem/química , Complexo de Reconhecimento de Origem/metabolismo , Origem de Replicação , Domínio AAA , Trifosfato de Adenosina/metabolismo , Animais , Proteínas de Ciclo Celular/genética , Microscopia Crioeletrônica , DNA/química , DNA/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Hidrólise , Proteínas de Manutenção de Minicromossomo/química , Proteínas de Manutenção de Minicromossomo/genética , Proteínas de Manutenção de Minicromossomo/metabolismo , Modelos Moleculares , Complexo de Reconhecimento de Origem/genética , Ligação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Origem de Replicação/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
8.
Nat Commun ; 11(1): 4067, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32792493

RESUMO

The brain is organized morphologically and functionally into a columnar structure. According to the radial unit hypothesis, neurons from the same lineage form a radial unit that contributes to column formation. However, the molecular mechanisms that link neuronal lineage and column formation remain elusive. Here, we show that neurons from the same lineage project to different columns under control of Down syndrome cell adhesion molecule (Dscam) in the fly brain. Dscam1 is temporally expressed in newly born neuroblasts and is inherited by their daughter neurons. The transient transcription of Dscam1 in neuroblasts enables the expression of the same Dscam1 splice isoform within cells of the same lineage, causing lineage-dependent repulsion. In the absence of Dscam1 function, neurons from the same lineage project to the same column. When the splice diversity of Dscam1 is reduced, column formation is significantly compromised. Thus, Dscam1 controls column formation through lineage-dependent repulsion.


Assuntos
Moléculas de Adesão Celular/metabolismo , Proteínas de Drosophila/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Isoformas de Proteínas/metabolismo , Animais , Axônios/metabolismo , Moléculas de Adesão Celular/genética , Células Cultivadas , Proteínas de Drosophila/genética , Drosophila melanogaster , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurogênese/genética , Neurogênese/fisiologia , Isoformas de Proteínas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
9.
PLoS Genet ; 16(8): e1008820, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32750048

RESUMO

The core planar polarity proteins are essential mediators of tissue morphogenesis, controlling both the polarised production of cellular structures and polarised tissue movements. During development the core proteins promote planar polarisation by becoming asymmetrically localised to opposite cell edges within epithelial tissues, forming intercellular protein complexes that coordinate polarity between adjacent cells. Here we describe a novel protein complex that regulates the asymmetric localisation of the core proteins in the Drosophila pupal wing. DAnkrd49 (an ankyrin repeat protein) and Bride of Doubletime (Bdbt, a non-canonical FK506 binding protein family member) physically interact, and regulate each other's levels in vivo. Loss of either protein results in a reduction in core protein asymmetry and disruption of the placement of trichomes at the distal edge of pupal wing cells. Post-translational modifications are thought to be important for the regulation of core protein behaviour and their sorting to opposite cell edges. Consistent with this, we find that loss of DAnkrd49 or Bdbt leads to reduced phosphorylation of the core protein Dishevelled and to decreased Dishevelled levels both at cell junctions and in the cytoplasm. Bdbt has previously been shown to regulate activity of the kinase Discs Overgrown (Dco, also known as Doubletime or Casein Kinase Iε), and Dco itself has been implicated in regulating planar polarity by phosphorylating Dsh as well as the core protein Strabismus. We demonstrate that DAnkrd49 and Bdbt act as dominant suppressors of Dco activity. These findings support a model whereby Bdbt and DAnkrd49 act together to modulate the activity of Dco during planar polarity establishment.


Assuntos
Caseína Quinase Iépsilon/metabolismo , Polaridade Celular , Proteínas de Drosophila/metabolismo , Morfogênese , Proteínas de Ligação a Tacrolimo/metabolismo , Animais , Caseína Quinase Iépsilon/genética , Proteínas Desgrenhadas/genética , Proteínas Desgrenhadas/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster , Mutação com Perda de Função , Ligação Proteica , Transporte Proteico , Proteínas de Ligação a Tacrolimo/genética , Asas de Animais/citologia , Asas de Animais/crescimento & desenvolvimento
10.
PLoS Genet ; 16(8): e1008989, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32810129

RESUMO

Drosophila Myc (dMyc), as a broad-spectrum transcription factor, can regulate the expression of a large number of genes to control diverse cellular processes, such as cell cycle progression, cell growth, proliferation and apoptosis. However, it remains largely unknown about whether dMyc can be involved in Drosophila innate immune response. Here, we have identified dMyc to be a negative regulator of Drosophila Imd pathway via the loss- and gain-of-function screening. We demonstrate that dMyc inhibits Drosophila Imd immune response via directly activating miR-277 transcription, which further inhibit the expression of imd and Tab2-Ra/b. Importantly, dMyc can improve the survival of flies upon infection, suggesting inhibiting Drosophila Imd pathway by dMyc is vital to restore immune homeostasis that is essential for survival. Taken together, our study not only reports a new dMyc-miR-277-imd/Tab2 axis involved in the negative regulation of Drosophila Imd pathway, and provides a new insight into the complex regulatory mechanism of Drosophila innate immune homeostasis maintenance.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/genética , Imunidade Inata/genética , MicroRNAs/genética , Fatores de Transcrição/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Divisão Celular/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Homeostase/genética , Humanos , Transdução de Sinais/genética , Fatores de Transcrição/metabolismo , Transcrição Genética/genética
11.
PLoS One ; 15(8): e0237662, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822370

RESUMO

The larvae of Drosophila melanogaster grow rapidly through use of a highly truncated cell cycle in which mitosis is entirely eliminated. The Drosophila homolog of the protooncogene transcription factor Myc plays a major role in promoting this endopolyploid (EP) growth. We have previously determined that the gene jim lovell (lov), which encodes a member of the BTB/POZ (Bric-a-brac, Tramtrack, Broad/Pox virus zinc finger) domain family of transcription factors, is also required for EP growth in one larval tissue, the trachea. Here we show that lov promotes EP growth in three further tissues indicating a fundamental role in this process. However, epistasis experiments revealed heterogeneity in lov's action in these tissues. Whereas in the tracheae and salivary glands lov acts downstream of Myc, in the fat body, reduced expression of lov does not impede the action of Myc, indicating an upstream action for the gene. We show here that lov's regulation of the gene uninflatable (uif) in the tracheae is a component of this difference. uif is required for tracheal EP growth downstream of Myc and lov but has no equivalent role in the fat body. Although Uif is a transmembrane component of the plasma membrane in the tracheae, its action downstream of Myc suggests an intracellular role for the protein in the tracheae. In addition to regulating uif expression in some tissues we also show that lov locates to the nucleolus, indicating it can function in both polymerase I and polymerase II transcriptional events. Our major finding is that tissue-specific mechanisms can interact with universal growth promotion by Myc to generate the individual endopolyploid organs of the larvae.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Fatores de Transcrição/metabolismo , Animais , Proteínas de Drosophila/análise , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Epistasia Genética , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Proteínas de Membrana/análise , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Poliploidia , Fatores de Transcrição/análise , Fatores de Transcrição/genética
12.
Nat Commun ; 11(1): 3962, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32770059

RESUMO

Social context can dampen or amplify the perception of touch, and touch in turn conveys nuanced social information. However, the neural mechanism behind social regulation of mechanosensation is largely elusive. Here we report that fruit flies exhibit a strong defensive response to mechanical stimuli to their wings. In contrast, virgin female flies being courted by a male show a compromised defensive response to the stimuli, but following mating the response is enhanced. This state-dependent switch is mediated by a functional reconfiguration of a neural circuit labelled with the Tmc-L gene in the ventral nerve cord. The circuit receives excitatory inputs from peripheral mechanoreceptors and coordinates the defensive response. While male cues suppress it via a doublesex (dsx) neuronal pathway, mating sensitizes it by stimulating a group of uterine neurons and consequently activating a leucokinin-dependent pathway. Such a modulation is crucial for the balance between defense against body contacts and sexual receptivity.


Assuntos
Drosophila melanogaster/fisiologia , Vias Neurais/fisiologia , Comportamento Sexual Animal/fisiologia , Alelos , Animais , Corte , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Feminino , Neurônios GABAérgicos/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Masculino , Mecanorreceptores/metabolismo , Mutação/genética , Neuropeptídeos/metabolismo , Útero/inervação , Asas de Animais/inervação
13.
Nature ; 585(7823): 85-90, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32699409

RESUMO

A relatively small number of proteins have been suggested to act as morphogens-signalling molecules that spread within tissues to organize tissue repair and the specification of cell fate during development. Among them are Wnt proteins, which carry a palmitoleate moiety that is essential for signalling activity1-3. How a hydrophobic lipoprotein can spread in the aqueous extracellular space is unknown. Several mechanisms, such as those involving lipoprotein particles, exosomes or a specific chaperone, have been proposed to overcome this so-called Wnt solubility problem4-6. Here we provide evidence against these models and show that the Wnt lipid is shielded by the core domain of a subclass of glypicans defined by the Dally-like protein (Dlp). Structural analysis shows that, in the presence of palmitoleoylated peptides, these glypicans change conformation to create a hydrophobic space. Thus, glypicans of the Dlp family protect the lipid of Wnt proteins from the aqueous environment and serve as a reservoir from which Wnt proteins can be handed over to signalling receptors.


Assuntos
Glipicanas/química , Glipicanas/metabolismo , Lipídeos , Transdução de Sinais , Proteínas Wnt/química , Proteínas Wnt/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Proteínas de Drosophila/química , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Ácidos Graxos Monoinsaturados/química , Ácidos Graxos Monoinsaturados/metabolismo , Feminino , Glipicanas/classificação , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lipídeos/química , Masculino , Modelos Moleculares , Mutação , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Ligação Proteica/genética , Domínios Proteicos , Transporte Proteico , Solubilidade , Proteína Wnt1/química , Proteína Wnt1/metabolismo
14.
Nature ; 584(7821): 415-419, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641829

RESUMO

Sexual dimorphism arises from genetic differences between male and female cells, and from systemic hormonal differences1-3. How sex hormones affect non-reproductive organs is poorly understood, yet highly relevant to health given the sex-biased incidence of many diseases4. Here we report that steroid signalling in Drosophila from the ovaries to the gut promotes growth of the intestine specifically in mated females, and enhances their reproductive output. The active ovaries of the fly produce the steroid hormone ecdysone, which stimulates the division and expansion of intestinal stem cells in two distinct proliferative phases via the steroid receptors EcR and Usp and their downstream targets Broad, Eip75B and Hr3. Although ecdysone-dependent growth of the female gut augments fecundity, the more active and more numerous intestinal stem cells also increase female susceptibility to age-dependent gut dysplasia and tumorigenesis, thus potentially reducing lifespan. This work highlights the trade-offs in fitness traits that occur when inter-organ signalling alters stem-cell behaviour to optimize organ size.


Assuntos
Drosophila melanogaster/metabolismo , Fertilidade/fisiologia , Intestinos/crescimento & desenvolvimento , Longevidade/fisiologia , Tamanho do Órgão/fisiologia , Ovário/metabolismo , Esteroides/metabolismo , Envelhecimento , Animais , Carcinogênese , Proliferação de Células , Copulação/fisiologia , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/anatomia & histologia , Drosophila melanogaster/citologia , Drosophila melanogaster/fisiologia , Ecdisona/metabolismo , Feminino , Mucosa Intestinal/anatomia & histologia , Mucosa Intestinal/citologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Intestinos/anatomia & histologia , Intestinos/citologia , Intestinos/patologia , Masculino , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores de Esteroides/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Fatores de Transcrição/metabolismo
15.
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
16.
Proc Natl Acad Sci U S A ; 117(28): 16606-16615, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32601210

RESUMO

Neural network function requires an appropriate balance of excitation and inhibition to be maintained by homeostatic plasticity. However, little is known about homeostatic mechanisms in the intact central brain in vivo. Here, we study homeostatic plasticity in the Drosophila mushroom body, where Kenyon cells receive feedforward excitation from olfactory projection neurons and feedback inhibition from the anterior paired lateral neuron (APL). We show that prolonged (4-d) artificial activation of the inhibitory APL causes increased Kenyon cell odor responses after the artificial inhibition is removed, suggesting that the mushroom body compensates for excess inhibition. In contrast, there is little compensation for lack of inhibition (blockade of APL). The compensation occurs through a combination of increased excitation of Kenyon cells and decreased activation of APL, with differing relative contributions for different Kenyon cell subtypes. Our findings establish the fly mushroom body as a model for homeostatic plasticity in vivo.


Assuntos
Drosophila/fisiologia , Corpos Pedunculados/fisiologia , Animais , Drosophila/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Homeostase , Neurônios/fisiologia , Odorantes/análise , Olfato
17.
PLoS One ; 15(7): e0232137, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614896

RESUMO

In sarcomeres, α-actinin crosslinks thin filaments and anchors them at the Z-disc. Drosophila melanogaster Zasp52 also localizes at Z-discs and interacts with α-actinin via its extended PDZ domain, thereby contributing to myofibril assembly and maintenance, yet the detailed mechanism of Zasp52 function is unknown. Here we show a strong genetic interaction between actin and Zasp52 during indirect flight muscle assembly, indicating that this interaction plays a critical role during myofibril assembly. Our results suggest that Zasp52 contains an actin-binding site, which includes the extended PDZ domain and the ZM region. Zasp52 binds with micromolar affinity to monomeric actin. A co-sedimentation assay indicates that Zasp52 can also bind to F-actin. Finally, we use in vivo rescue assays of myofibril assembly to show that the α-actinin-binding domain of Zasp52 is not sufficient for a full rescue of Zasp52 mutants suggesting additional contributions of Zasp52 actin-binding to myofibril assembly.


Assuntos
Actinas/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Drosophila/metabolismo , Miofibrilas/metabolismo , Animais , Proteínas de Transporte/química , Proteínas de Transporte/genética , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Drosophila melanogaster/metabolismo , Domínios PDZ , Ligação Proteica
18.
Nat Commun ; 11(1): 3568, 2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32678085

RESUMO

Dissemination of transformed cells is a key process in metastasis. Despite its importance, how transformed cells disseminate from an intact tissue and enter the circulation is poorly understood. Here, we use a fully developed tissue, Drosophila midgut, and describe the morphologically distinct steps and the cellular events occurring over the course of RasV12-transformed cell dissemination. Notably, RasV12-transformed cells formed the Actin- and Cortactin-rich invasive protrusions that were important for breaching the extracellular matrix (ECM) and visceral muscle. Furthermore, we uncovered the essential roles of the mechanosensory channel Piezo in orchestrating dissemination of RasV12-transformed cells. Collectively, our study establishes an in vivo model for studying how transformed cells migrate out from a complex tissue and provides unique insights into the roles of Piezo in invasive cell behavior.


Assuntos
Proteínas de Drosophila/metabolismo , Canais Iônicos/metabolismo , Mecanotransdução Celular , Invasividade Neoplásica/patologia , Proteínas ras/metabolismo , Animais , Membrana Basal/metabolismo , Membrana Basal/patologia , Transformação Celular Neoplásica , Modelos Animais de Doenças , Drosophila , Proteínas de Drosophila/genética , Vesículas Extracelulares/metabolismo , Trato Gastrointestinal/patologia , Genes ras , Canais Iônicos/genética , Metástase Neoplásica/patologia , Podossomos/metabolismo , Proteínas ras/genética
19.
Nucleic Acids Res ; 48(13): 7483-7501, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32510132

RESUMO

The MLE DExH helicase and the roX lncRNAs are essential components of the chromatin modifying Dosage Compensation Complex (DCC) in Drosophila. To explore the mechanism of ribonucleoprotein complex assembly, we developed vitRIP, an unbiased, transcriptome-wide in vitro assay that reveals RNA binding specificity. We found that MLE has intrinsic specificity for U-/A-rich sequences and tandem stem-loop structures and binds many RNAs beyond roX in vitro. The selectivity of the helicase for physiological substrates is further enhanced by the core DCC. Unwinding of roX2 by MLE induces a highly selective RNA binding surface in the unstructured C-terminus of the MSL2 subunit and triggers-specific association of MLE and roX2 with the core DCC. The exquisite selectivity of roX2 incorporation into the DCC thus originates from intimate cooperation between the helicase and the core DCC involving two distinct RNA selection principles and their mutual refinement.


Assuntos
Montagem e Desmontagem da Cromatina , RNA Longo não Codificante/metabolismo , Transcriptoma , Animais , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Clonagem Molecular/métodos , DNA Helicases/genética , DNA Helicases/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Ligação Proteica , RNA Longo não Codificante/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
20.
PLoS Genet ; 16(6): e1008861, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32525870

RESUMO

In metazoan germlines, the piRNA pathway acts as a genomic immune system, employing small RNA-mediated silencing to defend host DNA from the harmful effects of transposable elements (TEs). Expression of genomic TEs is proposed to initiate self regulation by increasing the production of repressive piRNAs, thereby "adapting" piRNA-mediated control to the most active TE families. Surprisingly, however, piRNA pathway proteins, which execute piRNA biogenesis and enforce silencing of targeted sequences, evolve rapidly and adaptively in animals. If TE silencing is ensured through piRNA biogenesis, what necessitates changes in piRNA pathway proteins? Here we used interspecific complementation to test for functional differences between Drosophila melanogaster and D. simulans alleles of three adaptively evolving piRNA pathway proteins: Armitage, Aubergine and Spindle-E. In contrast to piRNA-mediated transcriptional regulators examined in previous studies, these three proteins have cytoplasmic functions in piRNA maturation and post-transcriptional silencing. Across all three proteins we observed interspecific divergence in the regulation of only a handful of TE families, which were more robustly silenced by the heterospecific piRNA pathway protein. This unexpected result suggests that unlike transcriptional regulators, positive selection has not acted on cytoplasmic piRNA effector proteins to enhance their function in TE repression. Rather, TEs may evolve to "escape" silencing by host proteins. We further discovered that D. simulans alleles of aub and armi exhibit enhanced off-target effects on host transcripts in a D. melanogaster background, as well as modest reductions in the efficiency of piRNA biogenesis, suggesting that promiscuous binding of D. simulans Aub and Armi proteins to host transcripts reduces their participation in piRNA production. Avoidance of genomic auto-immunity may therefore be a critical target of selection. Our observations suggest that piRNA effector proteins are subject to an evolutionary trade-off between defending the host genome from the harmful effect of TEs while also minimizing collateral damage to host genes.


Assuntos
Autoimunidade/genética , Elementos de DNA Transponíveis/imunologia , Drosophila simulans/genética , Evolução Molecular , Genoma de Inseto/imunologia , RNA Interferente Pequeno/biossíntese , Alelos , Animais , Animais Geneticamente Modificados , Citoplasma/genética , Citoplasma/metabolismo , Elementos de DNA Transponíveis/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/imunologia , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/imunologia , Drosophila melanogaster/metabolismo , Drosophila simulans/metabolismo , Feminino , Regulação da Expressão Gênica/imunologia , Genoma de Inseto/genética , Masculino , Mutação , Interferência de RNA/imunologia
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