RESUMEN
In Drosophila, a dedicated olfactory channel senses a male pheromone, cis-vaccenyl acetate (cVA), promoting female courtship while repelling males. Here, we show that separate cVA-processing streams extract qualitative and positional information. cVA sensory neurons respond to concentration differences in a 5-mm range around a male. Second-order projection neurons encode the angular position of a male by detecting inter-antennal differences in cVA concentration, which are amplified through contralateral inhibition. At the third circuit layer, we identify 47 cell types with diverse input-output connectivity. One population responds tonically to male flies, a second is tuned to olfactory looming, while a third integrates cVA and taste to coincidentally promote female mating. The separation of olfactory features resembles the mammalian what and where visual streams; together with multisensory integration, this enables behavioral responses appropriate to specific ethological contexts.
Asunto(s)
Proteínas de Drosophila , Receptores Odorantes , Animales , Femenino , Masculino , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Conducta Sexual Animal/fisiología , Receptores Odorantes/metabolismo , Feromonas/metabolismo , Olfato/fisiología , Drosophila/metabolismo , Mamíferos/metabolismoRESUMEN
Asymmetric localization of oskar ribonucleoprotein (RNP) granules to the oocyte posterior is crucial for abdominal patterning and germline formation in the Drosophila embryo. We show that oskar RNP granules in the oocyte are condensates with solid-like physical properties. Using purified oskar RNA and scaffold proteins Bruno and Hrp48, we confirm in vitro that oskar granules undergo a liquid-to-solid phase transition. Whereas the liquid phase allows RNA incorporation, the solid phase precludes incorporation of additional RNA while allowing RNA-dependent partitioning of client proteins. Genetic modification of scaffold granule proteins or tethering the intrinsically disordered region of human fused in sarcoma (FUS) to oskar mRNA allowed modulation of granule material properties in vivo. The resulting liquid-like properties impaired oskar localization and translation with severe consequences on embryonic development. Our study reflects how physiological phase transitions shape RNA-protein condensates to regulate the localization and expression of a maternal RNA that instructs germline formation.
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Embrión no Mamífero/metabolismo , Animales , Gránulos de Ribonucleoproteínas Citoplasmáticas , Drosophila/embriología , Proteínas de Drosophila/genética , Desarrollo Embrionario , Oocitos/metabolismo , ARN/metabolismoRESUMEN
Predicting regulatory potential from primary DNA sequences or transcription factor binding patterns is not possible. However, the annotation of the genome by chromatin proteins, histone modifications, and differential compaction is largely sufficient to reveal the locations of genes and their differential activity states. The Polycomb Group (PcG) and Trithorax Group (TrxG) proteins are the central players in this cell type-specific chromatin organization. PcG function was originally viewed as being solely repressive and irreversible, as observed at the homeotic loci in flies and mammals. However, it is now clear that modular and reversible PcG function is essential at most developmental genes. Focusing mainly on recent advances, we review evidence for how PcG and TrxG patterns change dynamically during cell type transitions. The ability to implement cell type-specific transcriptional programming with exquisite fidelity is essential for normal development.
Asunto(s)
Proteínas Cromosómicas no Histona/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Regulación del Desarrollo de la Expresión Génica , Histonas/metabolismo , Proteínas del Grupo Polycomb/genética , Transcripción Genética , Animales , Cromatina/química , Cromatina/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Metilación de ADN , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citología , Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/metabolismo , Embrión de Mamíferos , Embrión no Mamífero , Sitios Genéticos , Histonas/genética , Ratones , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas del Grupo Polycomb/clasificación , Proteínas del Grupo Polycomb/metabolismo , Elementos de Respuesta , Especificidad de la Especie , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Before zygotic genome activation (ZGA), the quiescent genome undergoes reprogramming to transition into the transcriptionally active state. However, the mechanisms underlying euchromatin establishment during early embryogenesis remain poorly understood. Here, we show that histone H4 lysine 16 acetylation (H4K16ac) is maintained from oocytes to fertilized embryos in Drosophila and mammals. H4K16ac forms large domains that control nucleosome accessibility of promoters prior to ZGA in flies. Maternal depletion of MOF acetyltransferase leading to H4K16ac loss causes aberrant RNA Pol II recruitment, compromises the 3D organization of the active genomic compartments during ZGA, and causes downregulation of post-zygotically expressed genes. Germline depletion of histone deacetylases revealed that other acetyl marks cannot compensate for H4K16ac loss in the oocyte. Moreover, zygotic re-expression of MOF was neither able to restore embryonic viability nor onset of X chromosome dosage compensation. Thus, maternal H4K16ac provides an instructive function to the offspring, priming future gene activation.
Asunto(s)
Histonas/metabolismo , Lisina/metabolismo , Activación Transcripcional/genética , Acetilación , Animales , Secuencia de Bases , Segregación Cromosómica/genética , Secuencia Conservada , Compensación de Dosificación (Genética) , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriología , Drosophila melanogaster/genética , Embrión no Mamífero/metabolismo , Evolución Molecular , Femenino , Genoma , Histona Acetiltransferasas/genética , Histona Acetiltransferasas/metabolismo , Masculino , Mamíferos/genética , Ratones , Mutación/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Nucleosomas/metabolismo , Oocitos/metabolismo , Regiones Promotoras Genéticas , ARN Polimerasa II/metabolismo , Cromosoma X/metabolismo , Cigoto/metabolismoRESUMEN
Metabolic reprogramming is a key feature of many cancers, but how and when it contributes to tumorigenesis remains unclear. Here we demonstrate that metabolic reprogramming induced by mitochondrial fusion can be rate-limiting for immortalization of tumor-initiating cells (TICs) and trigger their irreversible dedication to tumorigenesis. Using single-cell transcriptomics, we find that Drosophila brain tumors contain a rapidly dividing stem cell population defined by upregulation of oxidative phosphorylation (OxPhos). We combine targeted metabolomics and in vivo genetic screening to demonstrate that OxPhos is required for tumor cell immortalization but dispensable in neural stem cells (NSCs) giving rise to tumors. Employing an in vivo NADH/NAD+ sensor, we show that NSCs precisely increase OxPhos during immortalization. Blocking OxPhos or mitochondrial fusion stalls TICs in quiescence and prevents tumorigenesis through impaired NAD+ regeneration. Our work establishes a unique connection between cellular metabolism and immortalization of tumor-initiating cells.
Asunto(s)
Neoplasias Encefálicas/metabolismo , Carcinogénesis/metabolismo , Transformación Celular Neoplásica/metabolismo , Dinámicas Mitocondriales , NAD/metabolismo , Células Madre Neoplásicas/metabolismo , Células-Madre Neurales/metabolismo , Fosforilación Oxidativa , Animales , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/patología , Carcinogénesis/genética , Carcinogénesis/patología , Transformación Celular Neoplásica/patología , Ciclo del Ácido Cítrico/genética , Biología Computacional , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Drosophila , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Glucólisis/genética , Espectrometría de Masas , Metabolómica , Microscopía Electrónica de Transmisión , Familia de Multigenes , Células-Madre Neurales/patología , Consumo de Oxígeno/genética , Interferencia de ARN , Especies Reactivas de Oxígeno/metabolismo , Análisis de la Célula Individual , Transcriptoma/genéticaRESUMEN
In developing organisms, spatially prescribed cell identities are thought to be determined by the expression levels of multiple genes. Quantitative tests of this idea, however, require a theoretical framework capable of exposing the rules and precision of cell specification over developmental time. We use the gap gene network in the early fly embryo as an example to show how expression levels of the four gap genes can be jointly decoded into an optimal specification of position with 1% accuracy. The decoder correctly predicts, with no free parameters, the dynamics of pair-rule expression patterns at different developmental time points and in various mutant backgrounds. Precise cellular identities are thus available at the earliest stages of development, contrasting the prevailing view of positional information being slowly refined across successive layers of the patterning network. Our results suggest that developmental enhancers closely approximate a mathematically optimal decoding strategy.
Asunto(s)
Proteínas Activadoras de GTPasa/genética , Regulación del Desarrollo de la Expresión Génica/genética , Redes Reguladoras de Genes/genética , Animales , Tipificación del Cuerpo/genética , Diferenciación Celular/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Embrión no Mamífero/metabolismo , Desarrollo Embrionario/genética , Proteínas Activadoras de GTPasa/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , Modelos Genéticos , Factores de Transcripción/metabolismoRESUMEN
The molecular events that direct nuclear pore complex (NPC) assembly toward nuclear envelopes have been conceptualized in two pathways that occur during mitosis or interphase, respectively. In gametes and embryonic cells, NPCs also occur within stacked cytoplasmic membrane sheets, termed annulate lamellae (AL), which serve as NPC storage for early development. The mechanism of NPC biogenesis at cytoplasmic membranes remains unknown. Here, we show that during Drosophila oogenesis, Nucleoporins condense into different precursor granules that interact and progress into NPCs. Nup358 is a key player that condenses into NPC assembly platforms while its mRNA localizes to their surface in a translation-dependent manner. In concert, Microtubule-dependent transport, the small GTPase Ran and nuclear transport receptors regulate NPC biogenesis in oocytes. We delineate a non-canonical NPC assembly mechanism that relies on Nucleoporin condensates and occurs away from the nucleus under conditions of cell cycle arrest.
Asunto(s)
Proteínas de Drosophila/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas de Complejo Poro Nuclear/metabolismo , Poro Nuclear/metabolismo , Oogénesis , Transporte Activo de Núcleo Celular , Animales , Proteínas de Drosophila/genética , Drosophila melanogaster , Femenino , Microtúbulos/metabolismo , Chaperonas Moleculares/genética , Proteínas de Complejo Poro Nuclear/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteína de Unión al GTP ran/genética , Proteína de Unión al GTP ran/metabolismoRESUMEN
Prion-like proteins can assume distinct conformational and physical states in the same cell. Sequence analysis suggests that prion-like proteins are prevalent in various species; however, it remains unclear what functional space they occupy in multicellular organisms. Here, we report the identification of a prion-like protein, Herzog (CG5830), through a multimodal screen in Drosophila melanogaster. Herzog functions as a membrane-associated phosphatase and controls embryonic patterning, likely being involved in TGF-ß/BMP and FGF/EGF signaling pathways. Remarkably, monomeric Herzog is enzymatically inactive and becomes active upon amyloid-like assembly. The prion-like domain of Herzog is necessary for both its assembly and membrane targeting. Removal of the prion-like domain impairs activity, while restoring assembly on the membrane using a heterologous prion-like domain and membrane-targeting motif can restore phosphatase activity. This study provides an example of a prion-like domain that allows an enzyme to gain essential functionality via amyloid-like assembly to control animal development.
Asunto(s)
Proteínas Amiloidogénicas/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriología , Desarrollo Embrionario , Fosfoproteínas Fosfatasas/metabolismo , Monoéster Fosfórico Hidrolasas/metabolismo , Proteínas Amiloidogénicas/química , Proteínas Amiloidogénicas/genética , Animales , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Fosfoproteínas Fosfatasas/química , Fosfoproteínas Fosfatasas/genética , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/genética , Priones/química , Dominios ProteicosRESUMEN
X chromosome regulation represents a prime example of an epigenetic phenomenon where coordinated regulation of a whole chromosome is required. In flies, this is achieved by transcriptional upregulation of X chromosomal genes in males to equalize the gene dosage differences in females. Chromatin-bound proteins and long noncoding RNAs (lncRNAs) constituting a ribonucleoprotein complex known as the male-specific lethal (MSL) complex or the dosage compensation complex mediate this process. MSL complex members decorate the male X chromosome, and their absence leads to male lethality. The male X chromosome is also enriched with histone H4 lysine 16 acetylation (H4K16ac), indicating that the chromatin compaction status of the X chromosome also plays an important role in transcriptional activation. How the X chromosome is specifically targeted and how dosage compensation is mechanistically achieved are central questions for the field. Here, we review recent advances, which reveal a complex interplay among lncRNAs, the chromatin landscape, transcription, and chromosome conformation that fine-tune X chromosome gene expression.
Asunto(s)
Compensación de Dosificación (Genética) , Cromosoma X/genética , Animales , Cromatina/genética , Cromatina/metabolismo , Proteínas de Drosophila/química , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Epigénesis Genética , Femenino , Genes Ligados a X , Código de Histonas/genética , Humanos , Masculino , Modelos Genéticos , Modelos Moleculares , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Factores de Transcripción/química , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Cromosoma X/metabolismoRESUMEN
The diversity of cell types and regulatory states in the brain, and how these change during aging, remains largely unknown. We present a single-cell transcriptome atlas of the entire adult Drosophila melanogaster brain sampled across its lifespan. Cell clustering identified 87 initial cell clusters that are further subclustered and validated by targeted cell-sorting. Our data show high granularity and identify a wide range of cell types. Gene network analyses using SCENIC revealed regulatory heterogeneity linked to energy consumption. During aging, RNA content declines exponentially without affecting neuronal identity in old brains. This single-cell brain atlas covers nearly all cells in the normal brain and provides the tools to study cellular diversity alongside other Drosophila and mammalian single-cell datasets in our unique single-cell analysis platform: SCope (http://scope.aertslab.org). These results, together with SCope, allow comprehensive exploration of all transcriptional states of an entire aging brain.
Asunto(s)
Envejecimiento , Encéfalo/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Redes Reguladoras de Genes , Análisis de la Célula Individual/métodos , Transcriptoma , Animales , Drosophila melanogaster/fisiología , Femenino , Perfilación de la Expresión Génica , MasculinoRESUMEN
Color vision extracts spectral information by comparing signals from photoreceptors with different visual pigments. Such comparisons are encoded by color-opponent neurons that are excited at one wavelength and inhibited at another. Here, we examine the circuit implementation of color-opponent processing in the Drosophila visual system by combining two-photon calcium imaging with genetic dissection of visual circuits. We report that color-opponent processing of UVshort/blue and UVlong/green is already implemented in R7/R8 inner photoreceptor terminals of "pale" and "yellow" ommatidia, respectively. R7 and R8 photoreceptors of the same type of ommatidia mutually inhibit each other directly via HisCl1 histamine receptors and receive additional feedback inhibition that requires the second histamine receptor Ort. Color-opponent processing at the first visual synapse represents an unexpected commonality between Drosophila and vertebrates; however, the differences in the molecular and cellular implementation suggest that the same principles evolved independently.
Asunto(s)
Percepción de Color , Visión de Colores , Proteínas de Drosophila/metabolismo , Células Fotorreceptoras de Invertebrados/metabolismo , Receptores Histamínicos/metabolismo , Animales , Drosophila , Proteínas de Drosophila/genética , Retroalimentación Fisiológica , Células Fotorreceptoras de Invertebrados/fisiología , Receptores Histamínicos/genéticaRESUMEN
Neurons use two main schemes to encode information: rate coding (frequency of firing) and temporal coding (timing or pattern of firing). While the importance of rate coding is well established, it remains controversial whether temporal codes alone are sufficient for controlling behavior. Moreover, the molecular mechanisms underlying the generation of specific temporal codes are enigmatic. Here, we show in Drosophila clock neurons that distinct temporal spike patterns, dissociated from changes in firing rate, encode time-dependent arousal and regulate sleep. From a large-scale genetic screen, we identify the molecular pathways mediating the circadian-dependent changes in ionic flux and spike morphology that rhythmically modulate spike timing. Remarkably, the daytime spiking pattern alone is sufficient to drive plasticity in downstream arousal neurons, leading to increased firing of these cells. These findings demonstrate a causal role for temporal coding in behavior and define a form of synaptic plasticity triggered solely by temporal spike patterns.
Asunto(s)
Plasticidad Neuronal , Sueño/fisiología , Potenciales de Acción , Animales , Relojes Circadianos/fisiología , Drosophila , Proteínas de Drosophila/antagonistas & inhibidores , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Modelos Neurológicos , Neuronas/metabolismo , Optogenética , Canales de Potasio/genética , Canales de Potasio/metabolismo , Canales de Potasio Calcio-Activados/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Transducción de Señal , ATPasa Intercambiadora de Sodio-Potasio/antagonistas & inhibidores , ATPasa Intercambiadora de Sodio-Potasio/genética , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Transmisión SinápticaRESUMEN
Embryonic cell fates are defined by transcription factors that are rapidly deployed, yet attempts to visualize these factors in vivo often fail because of slow fluorescent protein maturation. Here, we pioneer a protein tag, LlamaTag, which circumvents this maturation limit by binding mature fluorescent proteins, making it possible to visualize transcription factor concentration dynamics in live embryos. Implementing this approach in the fruit fly Drosophila melanogaster, we discovered stochastic bursts in the concentration of transcription factors that are correlated with bursts in transcription. We further used LlamaTags to show that the concentration of protein in a given nucleus heavily depends on transcription of that gene in neighboring nuclei; we speculate that this inter-nuclear signaling is an important mechanism for coordinating gene expression to delineate straight and sharp boundaries of gene expression. Thus, LlamaTags now make it possible to visualize the flow of information along the central dogma in live embryos.
Asunto(s)
Proteínas de Drosophila/genética , Drosophila melanogaster/metabolismo , Edición Génica/métodos , Factores de Transcripción/genética , Animales , Núcleo Celular/metabolismo , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crecimiento & desarrollo , Embrión no Mamífero/metabolismo , Embrión no Mamífero/patología , Regulación del Desarrollo de la Expresión Génica , Proteínas Fluorescentes Verdes/genética , Microscopía Confocal , Factores de Transcripción/metabolismoRESUMEN
Synapses are fundamental units of communication in the brain. The prototypical synapse-organizing complex neurexin-neuroligin mediates synapse development and function and is central to a shared genetic risk pathway in autism and schizophrenia. Neurexin's role in synapse development is thought to be mediated purely by its protein domains, but we reveal a requirement for a rare glycan modification. Mice lacking heparan sulfate (HS) on neurexin-1 show reduced survival, as well as structural and functional deficits at central synapses. HS directly binds postsynaptic partners neuroligins and LRRTMs, revealing a dual binding mode involving intrinsic glycan and protein domains for canonical synapse-organizing complexes. Neurexin HS chains also bind novel ligands, potentially expanding the neurexin interactome to hundreds of HS-binding proteins. Because HS structure is heterogeneous, our findings indicate an additional dimension to neurexin diversity, provide a molecular basis for fine-tuning synaptic function, and open therapeutic directions targeting glycan-binding motifs critical for brain development.
Asunto(s)
Heparitina Sulfato/metabolismo , Moléculas de Adhesión de Célula Nerviosa/metabolismo , Sinapsis/metabolismo , Secuencia de Aminoácidos , Animales , Proteínas de Unión al Calcio , Moléculas de Adhesión Celular Neuronal/antagonistas & inhibidores , Moléculas de Adhesión Celular Neuronal/genética , Moléculas de Adhesión Celular Neuronal/metabolismo , Drosophila , Proteínas de Drosophila/antagonistas & inhibidores , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Femenino , Glicopéptidos/análisis , Heparitina Sulfato/química , Humanos , Proteínas de la Membrana , Ratones , Ratones Endogámicos C57BL , Proteínas del Tejido Nervioso , Moléculas de Adhesión de Célula Nerviosa/antagonistas & inhibidores , Moléculas de Adhesión de Célula Nerviosa/genética , Neuronas/citología , Neuronas/metabolismo , Unión Proteica , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Ratas , Alineación de SecuenciaRESUMEN
Arc/Arg3.1 is required for synaptic plasticity and cognition, and mutations in this gene are linked to autism and schizophrenia. Arc bears a domain resembling retroviral/retrotransposon Gag-like proteins, which multimerize into a capsid that packages viral RNA. The significance of such a domain in a plasticity molecule is uncertain. Here, we report that the Drosophila Arc1 protein forms capsid-like structures that bind darc1 mRNA in neurons and is loaded into extracellular vesicles that are transferred from motorneurons to muscles. This loading and transfer depends on the darc1-mRNA 3' untranslated region, which contains retrotransposon-like sequences. Disrupting transfer blocks synaptic plasticity, suggesting that transfer of dArc1 complexed with its mRNA is required for this function. Notably, cultured cells also release extracellular vesicles containing the Gag region of the Copia retrotransposon complexed with its own mRNA. Taken together, our results point to a trans-synaptic mRNA transport mechanism involving retrovirus-like capsids and extracellular vesicles.
Asunto(s)
Proteínas del Citoesqueleto/metabolismo , Productos del Gen gag/genética , Cuerpos Multivesiculares/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Terminales Presinápticos/metabolismo , ARN Mensajero/metabolismo , Animales , Transporte Biológico , Células Cultivadas , Proteínas del Citoesqueleto/química , Proteínas del Citoesqueleto/genética , Drosophila , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Productos del Gen gag/química , Proteínas del Tejido Nervioso/química , Proteínas del Tejido Nervioso/genética , Unión Neuromuscular/metabolismo , Plasticidad Neuronal , Péptido Hidrolasas/genética , Péptido Hidrolasas/metabolismo , Terminales Presinápticos/fisiología , Unión Proteica , Dominios Proteicos , Retroelementos/genéticaRESUMEN
Transcription factors regulate the molecular, morphological, and physiological characteristics of neurons and generate their impressive cell-type diversity. To gain insight into the general principles that govern how transcription factors regulate cell-type diversity, we used large-scale single-cell RNA sequencing to characterize the extensive cellular diversity in the Drosophila optic lobes. We sequenced 55,000 single cells and assigned them to 52 clusters. We validated and annotated many clusters using RNA sequencing of FACS-sorted single-cell types and cluster-specific genes. To identify transcription factors responsible for inducing specific terminal differentiation features, we generated a "random forest" model, and we showed that the transcription factors Apterous and Traffic-jam are required in many but not all cholinergic and glutamatergic neurons, respectively. In fact, the same terminal characters often can be regulated by different transcription factors in different cell types, arguing for extensive phenotypic convergence. Our data provide a deep understanding of the developmental and functional specification of a complex brain structure.
Asunto(s)
Drosophila melanogaster/embriología , Regulación del Desarrollo de la Expresión Génica/fisiología , Neurogénesis/fisiología , Animales , Diferenciación Celular , Neuronas Colinérgicas/fisiología , Análisis por Conglomerados , Simulación por Computador , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Perfilación de la Expresión Génica/métodos , Proteínas de Homeodominio , Proteínas con Homeodominio LIM/metabolismo , Factores de Transcripción Maf de Gran Tamaño/metabolismo , Neuroglía/fisiología , Neuronas/fisiología , Neurotransmisores/genética , Neurotransmisores/fisiología , Lóbulo Óptico de Animales no Mamíferos/fisiología , Fenotipo , Proteínas Proto-Oncogénicas/metabolismo , Análisis de Secuencia de ARN/métodos , Análisis de la Célula Individual/métodos , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/fisiologíaRESUMEN
Perceptual decisions require the accumulation of sensory information to a response criterion. Most accounts of how the brain performs this process of temporal integration have focused on evolving patterns of spiking activity. We report that subthreshold changes in membrane voltage can represent accumulating evidence before a choice. αß core Kenyon cells (αßc KCs) in the mushroom bodies of fruit flies integrate odor-evoked synaptic inputs to action potential threshold at timescales matching the speed of olfactory discrimination. The forkhead box P transcription factor (FoxP) sets neuronal integration and behavioral decision times by controlling the abundance of the voltage-gated potassium channel Shal (KV4) in αßc KC dendrites. αßc KCs thus tailor, through a particular constellation of biophysical properties, the generic process of synaptic integration to the demands of sequential sampling.
Asunto(s)
Dendritas/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/fisiología , Potenciales de Acción/efectos de los fármacos , Animales , Bario/farmacología , Conducta Animal/efectos de los fármacos , Encéfalo/metabolismo , Encéfalo/patología , Ciclohexanoles/farmacología , Proteínas de Drosophila/genética , Femenino , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Masculino , Neuronas/citología , Neuronas/metabolismo , Técnicas de Placa-Clamp , Receptores Odorantes/metabolismo , Canales de Potasio Shal/genética , Canales de Potasio Shal/metabolismo , Olfato , Sinapsis/metabolismoRESUMEN
Myriad experiences produce transient memory, yet, contingent on the internal state of the organism and the saliency of the experience, only some memories persist over time. How experience and internal state influence the duration of memory at the molecular level remains unknown. A self-assembled aggregated state of Drosophila Orb2A protein is required specifically for long-lasting memory. We report that in the adult fly brain the mRNA encoding Orb2A protein exists in an unspliced non-protein-coding form. The convergence of experience and internal drive transiently increases the spliced protein-coding Orb2A mRNA. A screen identified pasilla, the fly ortholog of mammalian Nova-1/2, as a mediator of Orb2A mRNA processing. A single-nucleotide substitution in the intronic region that reduces Pasilla binding and intron removal selectively impairs long-term memory. We posit that pasilla-mediated processing of unspliced Orb2A mRNA integrates experience and internal state to control Orb2A protein abundance and long-term memory formation.
Asunto(s)
Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Intrones , Memoria a Largo Plazo , Ribonucleoproteínas/metabolismo , Factores de Transcripción/genética , Factores de Escisión y Poliadenilación de ARNm/genética , Animales , Secuencia de Bases , Conducta Animal , Encéfalo/metabolismo , Condicionamiento Psicológico , Proteínas de Drosophila/química , Drosophila melanogaster/genética , Aprendizaje , Modelos Animales , Motivación , Mutación , Isoformas de Proteínas/metabolismo , Empalme del ARN , Factores de Transcripción/química , Factores de Transcripción/metabolismo , Factores de Escisión y Poliadenilación de ARNm/química , Factores de Escisión y Poliadenilación de ARNm/metabolismoRESUMEN
Whether and how histone post-translational modifications and the proteins that bind them drive 3D genome organization remains unanswered. Here, we evaluate the contribution of H3K9-methylated constitutive heterochromatin to 3D genome organization in Drosophila tissues. We find that the predominant organizational feature of wild-type tissues is the segregation of euchromatic chromosome arms from heterochromatic pericentromeres. Reciprocal perturbation of HP1aâ H3K9me binding, using a point mutation in the HP1a chromodomain or replacement of the replication-dependent histone H3 with H3K9R mutant histones, revealed that HP1a binding to methylated H3K9 in constitutive heterochromatin is required to limit contact frequency between pericentromeres and chromosome arms and regulate the distance between arm and pericentromeric regions. Surprisingly, the self-association of pericentromeric regions is largely preserved despite the loss of H3K9 methylation and HP1a occupancy. Thus, the HP1aâ H3K9 interaction contributes to but does not solely drive the segregation of euchromatin and heterochromatin inside the nucleus.
Asunto(s)
Homólogo de la Proteína Chromobox 5 , Proteínas Cromosómicas no Histona , Proteínas de Drosophila , Drosophila melanogaster , Heterocromatina , Histonas , Heterocromatina/metabolismo , Heterocromatina/genética , Animales , Histonas/metabolismo , Histonas/genética , Proteínas Cromosómicas no Histona/metabolismo , Proteínas Cromosómicas no Histona/genética , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Metilación , Eucromatina/metabolismo , Eucromatina/genética , Centrómero/metabolismo , Centrómero/genética , Unión Proteica , Genoma de los Insectos , Segregación Cromosómica , Procesamiento Proteico-PostraduccionalRESUMEN
INTS11 and CPSF73 are metal-dependent endonucleases for Integrator and pre-mRNA 3'-end processing, respectively. Here, we show that the INTS11 binding partner BRAT1/CG7044, a factor important for neuronal fitness, stabilizes INTS11 in the cytoplasm and is required for Integrator function in the nucleus. Loss of BRAT1 in neural organoids leads to transcriptomic disruption and precocious expression of neurogenesis-driving transcription factors. The structures of the human INTS9-INTS11-BRAT1 and Drosophila dIntS11-CG7044 complexes reveal that the conserved C terminus of BRAT1/CG7044 is captured in the active site of INTS11, with a cysteine residue directly coordinating the metal ions. Inspired by these observations, we find that UBE3D is a binding partner for CPSF73, and UBE3D likely also uses a conserved cysteine residue to directly coordinate the active site metal ions. Our studies have revealed binding partners for INTS11 and CPSF73 that behave like cytoplasmic chaperones with a conserved impact on the nuclear functions of these enzymes.