The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Michael Bate - One of the best experts on this subject based on the ideXlab platform.
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Specific muscle identities are regulated by Krüppel during Drosophila Embryogenesis.
Development (Cambridge England), 1997Co-Authors: Mar Ruiz-gómez, Susana Romani, Christine Hartmann, Herbert Jäckle, Michael BateAbstract:During Drosophila Embryogenesis, mesodermal cells are recruited to form a complex pattern of larval muscles. The formation of the pattern is initiated by the segregation of a special class of founder myoblasts. Single founders fuse with neighbouring nonfounder myoblasts to form the precursors of individual muscles. Founders and the muscles that they give rise to have specific patterns of gene expression and it has been suggested that it is the expression of these founder cell genes that determines individual muscle attributes such as size, shape, insertion sites and innervation. We find that the segmentation gene Kruppel is expressed in a subset of founders and muscles, regulates specific patterns of gene expression in these cells and is required for the acquisition of proper muscle identity. We show that gain and loss of Kruppel expression in sibling founder cells is sufficient to switch these cells, and the muscles that they give rise to, between alternative cell fates.
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Muscle development is independent of innervation during Drosophila Embryogenesis.
Development (Cambridge England), 1993Co-Authors: Kendal Broadie, Michael BateAbstract:We have examined the role of innervation in directing embryonic myogenesis, using a mutant (prospero), which delays the pioneering of peripheral motor nerves of the Drosophila embryo. In the absence of motor nerves, myoblasts fuse normally to form syncytial myotubes, myotubes form normal attachments to the epidermis, and a larval musculature comparable to the wild-type pattern is generated and maintained. Likewise, the twist-expressing myoblasts that prefigure the adult musculature segregate normally in the absence of motor nerves, migrate to their final embryonic positions and continue to express twist until the end of embryonic development. In the absence of motor nerves, myotubes uncouple at the correct developmental stage to form single cells. Subsequently, uninnervated myotubes develop the mature electrical and contractile properties of larval muscles with a time course indistinguishable from normally innervated myotubes. We conclude that innervation plays no role in the patterning, morphogenesis, maintenance or physiological development of the somatic muscles in the Drosophila embryo.
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Activity-dependent development of the neuromuscular synapse during Drosophila Embryogenesis
Neuron, 1993Co-Authors: Kendal Broadie, Michael BateAbstract:Abstract In Drosophila, mutations in specific ion channel genes can increase or decrease the level of neural/synaptic activity. We have used these genetic tools, in combination with classical pharmacological agents; to modulate neural activity during Embryogenesis and examined effects on the differentiation of an identified neuromuscular junction. We find that electrical activity is required for the neural induction of transmitter receptor expression during synaptogenesis. Likewise, neural electrical activity is required to localize transmitter receptors to the synaptic site. In muscles with activity-blocked synapses, a low level of receptors is expressed homogeneously in the muscle membrane as in muscles developing without innervation. Thus, presynaptic electrical activity is required to mediate the neural induction of the transmitter receptor field in the postsynaptic membrane.
Michael B Eisen - One of the best experts on this subject based on the ideXlab platform.
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Drosophila Embryogenesis scales uniformly across temperature in developmentally diverse species
PLOS Genetics, 2014Co-Authors: Steven Gregory Kuntz, Michael B EisenAbstract:Temperature affects both the timing and outcome of animal development, but the detailed effects of temperature on the progress of early development have been poorly characterized. To determine the impact of temperature on the order and timing of events during Drosophila melanogaster Embryogenesis, we used time-lapse imaging to track the progress of embryos from shortly after egg laying through hatching at seven precisely maintained temperatures between 17.5°C and 32.5°C. We employed a combination of automated and manual annotation to determine when 36 milestones occurred in each embryo. D. melanogaster Embryogenesis takes 33 hours at 17.5°C, and accelerates with increasing temperature to a low of 16 hours at 27.5°C, above which Embryogenesis slows slightly. Remarkably, while the total time of Embryogenesis varies over two fold, the relative timing of events from cellularization through hatching is constant across temperatures. To further explore the relationship between temperature and Embryogenesis, we expanded our analysis to cover ten additional Drosophila species of varying climatic origins. Six of these species, like D. melanogaster, are of tropical origin, and Embryogenesis time at different temperatures was similar for them all. D. mojavensis, a sub-tropical fly, develops slower than the tropical species at lower temperatures, while D. virilis, a temperate fly, exhibits slower development at all temperatures. The alpine sister species D. persimilis and D. pseudoobscura develop as rapidly as tropical flies at cooler temperatures, but exhibit diminished acceleration above 22.5°C and have drastically slowed development by 30°C. Despite ranging from 13 hours for D. erecta at 30°C to 46 hours for D. virilis at 17.5°C, the relative timing of events from cellularization through hatching is constant across all species and temperatures examined here, suggesting the existence of a previously unrecognized timer controlling the progress of Embryogenesis that has been tuned by natural selection as each species diverges.
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Drosophila Embryogenesis scales uniformly across temperature and developmentally diverse species
bioRxiv, 2013Co-Authors: Steven Gregory Kuntz, Michael B EisenAbstract:Temperature affects both the timing and outcome of animal development, but the detailed effects of temperature on the progress of early development have been poorly characterized. To determine the impact of temperature on the order and timing of events during Drosophila melanogaster Embryogenesis, we used time-lapse imaging to track the progress of embryos from shortly after egg laying through hatching at seven precisely maintained temperatures between 17.5°C and 32.5°C. We employed a combination of automated and manual annotation to determine when 36 milestones occurred in each embryo. D. melanogaster Embryogenesis takes 33 hours at 17.5°C, and accelerates with increasing temperature to a low of 16 hours at 27.5°C, above which Embryogenesis slows slightly. Remarkably, while the total time of Embryogenesis varies over two fold, the relative timing of events from cellularization through hatching is constant across temperatures. To further explore the relationship between temperature and Embryogenesis, we expanded our analysis to cover ten additional Drosophila species of varying climatic origins. Six of these species, like D. melanogaster, are of tropical origin, and Embryogenesis time at different temperatures was similar for them all. D. mojavensis, a sub-tropical fly, develops slower than the tropical species at lower temperatures, while D. virilis, a temperate fly, exhibits slower development at all temperatures. The alpine sister species D. persimilis and D. pseudoobscura develop as rapidly as tropical flies at cooler temperatures, but exhibit diminished acceleration above 22.5°C and have drastically slowed development by 30°C. Despite ranging from 13 hours for D. erecta at 30°C to 46 hours for D. virilis at 17.5°C, the relative timing of events from cellularization through hatching is constant across all of the species and temperatures examined here, suggesting the existence of a previously unrecognized timer controlling the progress of Embryogenesis that has been tuned by natural selection in response to the thermal environment in which each species lives.
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Drosophila Embryogenesis scales uniformly across temperature in developmentally diverse species
arXiv: Populations and Evolution, 2013Co-Authors: Steven Gregory Kuntz, Michael B EisenAbstract:Temperature affects both the timing and outcome of animal development, but the detailed effects of temperature on the progress of early development have been poorly characterized. To determine the impact of temperature on the order and timing of events during Drosophila melanogaster Embryogenesis, we used time-lapse imaging to track the progress of embryos from shortly after egg laying through hatching at seven precisely maintained temperatures between 17.5C and 32.5C. We employed a combination of automated and manual annotation to determine when 36 milestones occurred in each embryo. D. melanogaster Embryogenesis takes ~33 hours at 17.5C, and accelerates with increasing temperature to 16 hours at 27.5C, above which Embryogenesis slows slightly. Remarkably, while the total time of Embryogenesis varies over two fold, the relative timing of events from cellularization through hatching is constant across temperatures. To further explore the relationship between temperature and Embryogenesis, we expanded our analysis to cover ten additional Drosophila species of varying climatic origins. Six of these species, like D. melanogaster, are of tropical origin, and Embryogenesis time at different temperatures was similar for them all. D. mojavensis, a sub-tropical fly, develops slower than the tropical species at lower temperatures, while D. virilis, a temperate fly, exhibits slower development at all temperatures. The alpine sister species D. persimilis and D. pseudoobscura develop as rapidly as tropical flies at cooler temperatures, but exhibit diminished acceleration above 22.5C and have drastically slowed development by 30C. Despite ranging from 13 hours for D. erecta at 30C to 46 hours for D. virilis at 17.5C, the relative timing of events from cellularization through hatching is constant across all species and temperatures, suggesting the existence of a timer controlling Embryogenesis.
Robert Delotto - One of the best experts on this subject based on the ideXlab platform.
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Ventralizing signal determined by protease activation in Drosophila Embryogenesis.
Nature, 1994Co-Authors: Cynthia L. Smith, Robert DelottoAbstract:Specification of dorsal-ventral cell fate during Drosophila Embryogenesis is mediated by a signal transduction pathway. Asymmetry of cell fates arises through the spatially restricted production of a ligand in an extracellular compartment called the perivitelline space. The snake and easter genes are required for the production of the ligand and they encode the proenzyme form of secreted extracellular serine proteases. We have examined the effect of producing a preactivated form of the snake protease on the generation of dorsal-ventral polarity. SP6 RNA microinjection experiments reveal that different cell fates acquired at cellular blastoderm can be specified by the amount and spatial distribution of activated snake protein. Our results support a protease cascade model in which localized activation of uniformly distributed protease proenzymes leads to the spatially restricted production of ligand in the perivitelline space on the ventral side of the embryo.
Haifan Lin - One of the best experts on this subject based on the ideXlab platform.
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The Role of Maternal HP1a in Early Drosophila Embryogenesis via Regulation of Maternal Transcript Production.
Genetics, 2018Co-Authors: Ah Rume Park, Na Liu, Nils Neuenkirchen, Qiaozhi Guo, Haifan LinAbstract:Heterochromatin protein 1a (HP1a) is a highly conserved and versatile epigenetic factor that can both silence and activate transcription. However, the function of HP1a in development has been underinvestigated. Here, we report the role of maternal HP1a in producing maternal transcripts that drive early Drosophila Embryogenesis. Maternal HP1a upregulates genes involved in translation, mRNA splicing, and cell division, but downregulates genes involved in neurogenesis, organogenesis, and germline development, which all occur later in development. Our study reveals the earliest contribution of HP1a during oogenesis in regulating the production of maternal transcripts that drive early Drosophila Embryogenesis.
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PIWI proteins are essential for early Drosophila Embryogenesis.
Developmental Biology, 2014Co-Authors: Sneha Ramesh Mani, Heather B. Megosh, Haifan LinAbstract:PIWI proteins, a subfamily of the ARGONAUTE/PIWI protein family, have been implicated in transcriptional and posttranscriptional gene regulation and transposon silencing mediated by small non-coding RNAs, especially piRNAs. Although these proteins are known to be required for germline development, their somatic function remains elusive. Here, we examine the maternal function of all three PIWI proteins in Drosophila; Piwi, Aubergine (Aub) and Argonaute3 (Ago3) during early Embryogenesis. In syncytial embryos, Piwi displays an embryonic stage-dependent localization pattern. Piwi is localized in the cytoplasm during mitotic cycles 1–10. Between cycles 11 and 14, Piwi remains in the cytoplasm during mitosis but moves into the somatic nucleus during interphase. Beyond cycle 14, it stays in the nucleus. Aub and Ago3 are diffusely cytoplasmic from cycle 1 to 14. Embryos maternally depleted of any one of the three PIWI proteins display severe mitotic defects, including abnormal chromosome and nuclear morphology, cell cycle arrest, asynchronous nuclear division and aberrant nuclear migration. Furthermore, all three PIWI proteins are required for the assembly of mitotic machinery and progression through mitosis. Embryos depleted of maternal PIWI proteins also exhibit chromatin organization abnormalities. These observations indicate that maternal Piwi, Aub and Ago3 play a critical role in the maintenance of chromatin structure and cell cycle progression during early Embryogenesis, with compromised chromatin integrity as a possible cause of the observed mitotic defects. Our study demonstrates the essential function of PIWI proteins in the first phase of somatic development.
Eileen E. M. Furlong - One of the best experts on this subject based on the ideXlab platform.
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Lineage-Resolved Enhancer and Promoter Usage during a Time Course of Embryogenesis.
Developmental cell, 2020Co-Authors: James P. Reddington, Rebecca Rodríguez Viales, David A. Garfield, Olga M. Sigalova, Aslihan Karabacak Calviello, Raquel Marco-ferreres, Charles Girardot, Jacob F. Degner, Uwe Ohler, Eileen E. M. FurlongAbstract:Summary Enhancers are essential drivers of cell states, yet the relationship between accessibility, regulatory activity, and in vivo lineage commitment during Embryogenesis remains poorly understood. Here, we measure chromatin accessibility in isolated neural and mesodermal lineages across a time course of Drosophila Embryogenesis. Promoters, including tissue-specific genes, are often constitutively open, even in contexts where the gene is not expressed. In contrast, the majority of distal elements have dynamic, tissue-specific accessibility. Enhancer priming appears rarely within a lineage, perhaps reflecting the speed of Drosophila Embryogenesis. However, many tissue-specific enhancers are accessible in other lineages early on and become progressively closed as Embryogenesis proceeds. We demonstrate the usefulness of this tissue- and time-resolved resource to definitively identify single-cell clusters, to uncover predictive motifs, and to identify many regulators of tissue development. For one such predicted neural regulator, l(3)neo38, we generate a loss-of-function mutant and uncover an essential role for neuromuscular junction and brain development.
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Non-coding RNA Expression, Function, and Variation during Drosophila Embryogenesis.
Current biology : CB, 2018Co-Authors: Ignacio E. Schor, Giovanni Bussotti, Matilda Males, Mattia Forneris, Rebecca Rodríguez Viales, Anton J. Enright, Eileen E. M. FurlongAbstract:Summary Long non-coding RNAs (lncRNAs) can often function in the regulation of gene expression during development; however, their generality as essential regulators in developmental processes and organismal phenotypes remains unclear. Here, we performed a tailored investigation of lncRNA expression and function during Drosophila Embryogenesis, interrogating multiple stages, tissue specificity, nuclear localization, and genetic backgrounds. Our results almost double the number of annotated lncRNAs expressed at these embryonic stages. lncRNA levels are generally positively correlated with those of their neighboring genes, with little evidence of transcriptional interference. Using fluorescent in situ hybridization, we report the spatiotemporal expression of 15 new lncRNAs, revealing very dynamic tissue-specific patterns. Despite this, deletion of selected lncRNA genes had no obvious developmental defects or effects on viability under standard and stressed conditions. However, two lncRNA deletions resulted in modest expression changes of a small number of genes, suggesting that they fine-tune expression of non-essential genes. Several lncRNAs have strain-specific expression, indicating that they are not fixed within the population. This intra-species variation across genetic backgrounds may thereby be a useful tool to distinguish rapidly evolving lncRNAs with as yet non-essential roles.
