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Insect Molecular Biology Jun 2024In this study, we identified and assembled a strain of American nodavirus (ANV) in the Phlebotomus papatasi-derived PP9ad cell line. This strain most closely resembles...
In this study, we identified and assembled a strain of American nodavirus (ANV) in the Phlebotomus papatasi-derived PP9ad cell line. This strain most closely resembles Flock House virus and ANV identified in the Drosophila melanogaster S2/S2R cell line. Through small RNA sequencing and analysis, we demonstrate that ANV replication in PP9ad cells is primarily targeted by the exogenous small interfering RNA (exo-siRNA) pathway, with minimal engagement from the PIWI-interacting RNA (piRNA) pathway. In mosquitoes such as Aedes and Culex, the PIWI pathway is expanded and specialised, which actively limits virus replication. This is unlike in Drosophila spp., where the piRNA pathway does not restrict viral replication. In Lutzomyia sandflies (family Psychodidae), close relatives of Phlebotomus species and Drosophila, there appears to be an absence of virus-derived piRNAs. To investigate whether this absence is due to a lack of PIWI pathway proteins, we analysed the piRNA and siRNA diversity and repertoire in PP9ad cells. Previous assemblies of P. papatasi genome (Ppap_1.0) have revealed a patchy repertoire of the siRNA and piRNA pathways. Our analysis of the updated P. papatasi genome (Ppap_2.1) has shown no PIWI protein expansion in sandflies. We found that both siRNA and piRNA pathways are transcriptionally active in PP9ad cells, with genomic mapping of small RNAs generating typical piRNA signatures. Our results suggest that the piRNA pathway may not respond to virus replication in these cells, but an antiviral response is mounted via the exo-siRNA pathway.
PubMed: 38847568
DOI: 10.1111/imb.12932 -
Cell Reports Jun 2024High TRABD expression is associated with tau pathology in patients with Alzheimer's disease; however, the function of TRABD is unknown. Human TRABD encodes a...
High TRABD expression is associated with tau pathology in patients with Alzheimer's disease; however, the function of TRABD is unknown. Human TRABD encodes a mitochondrial outer-membrane protein. The loss of TRABD resulted in mitochondrial fragmentation, and TRABD overexpression led to mitochondrial clustering and fusion. The C-terminal tail of the TRABD anchored to the mitochondrial outer membrane and the TraB domain could form homocomplexes. Additionally, TRABD forms complexes with MFN2, MIGA2, and PLD6 to facilitate mitochondrial fusion. Flies lacking dTRABD are viable and have normal lifespans. However, aging flies exhibit reduced climbing ability and abnormal mitochondrial morphology in their muscles. The expression of dTRABD is increased in aged flies. dTRABD overexpression leads to neurodegeneration and enhances tau toxicity in fly eyes. The overexpression of dTRABD also increased reactive oxygen species (ROS), ATP production, and protein turnover in the mitochondria. This study suggested that TRABD-induced mitochondrial malfunctions contribute to age-related neurodegeneration.
Topics: Animals; Mitochondria; Homeostasis; Humans; Reactive Oxygen Species; Drosophila melanogaster; tau Proteins; Drosophila Proteins; Mitochondrial Dynamics; Mitochondrial Proteins; Mitochondrial Membranes; Membrane Proteins; Aging; GTP Phosphohydrolases
PubMed: 38843396
DOI: 10.1016/j.celrep.2024.114304 -
ELife Jun 2024The atypical cadherins Fat and Dachsous (Ds) signal through the Hippo pathway to regulate growth of numerous organs, including the wing. Here, we find that Ds-Fat...
The atypical cadherins Fat and Dachsous (Ds) signal through the Hippo pathway to regulate growth of numerous organs, including the wing. Here, we find that Ds-Fat signaling tunes a unique feature of cell proliferation found to control the rate of wing growth during the third instar larval phase. The duration of the cell cycle increases in direct proportion to the size of the wing, leading to linear-like growth during the third instar. Ds-Fat signaling enhances the rate at which the cell cycle lengthens with wing size, thus diminishing the rate of wing growth. We show that this results in a complex but stereotyped relative scaling of wing growth with body growth in . Finally, we examine the dynamics of Fat and Ds protein distribution in the wing, observing graded distributions that change during growth. However, the significance of these dynamics is unclear since perturbations in expression have negligible impact on wing growth.
Topics: Animals; Wings, Animal; Drosophila Proteins; Cell Cycle; Signal Transduction; Drosophila melanogaster; Cadherins; Larva; Cell Proliferation; Cell Adhesion Molecules
PubMed: 38842917
DOI: 10.7554/eLife.91572 -
The Journal of Cell Biology Sep 2024Extracellular vesicles (EVs) are released by many cell types, including neurons, carrying cargoes involved in signaling and disease. It is unclear whether EVs promote...
Extracellular vesicles (EVs) are released by many cell types, including neurons, carrying cargoes involved in signaling and disease. It is unclear whether EVs promote intercellular signaling or serve primarily to dispose of unwanted materials. We show that loss of multivesicular endosome-generating endosomal sorting complex required for transport (ESCRT) machinery disrupts release of EV cargoes from Drosophila motor neurons. Surprisingly, ESCRT depletion does not affect the signaling activities of the EV cargo Synaptotagmin-4 (Syt4) and disrupts only some signaling activities of the EV cargo evenness interrupted (Evi). Thus, these cargoes may not require intercellular transfer via EVs, and instead may be conventionally secreted or function cell-autonomously in the neuron. We find that EVs are phagocytosed by glia and muscles, and that ESCRT disruption causes compensatory autophagy in presynaptic neurons, suggesting that EVs are one of several redundant mechanisms to remove cargoes from synapses. Our results suggest that synaptic EV release serves primarily as a proteostatic mechanism for certain cargoes.
Topics: Animals; Endosomal Sorting Complexes Required for Transport; Extracellular Vesicles; Drosophila Proteins; Signal Transduction; Drosophila melanogaster; Synapses; Motor Neurons; Autophagy; Synaptotagmins; Neuroglia
PubMed: 38842573
DOI: 10.1083/jcb.202405025 -
Biology Open Jun 2024Bazooka/Par-3 (Baz) is an evolutionarily conserved scaffold protein that functions as a master regulator for the establishment and maintenance of cell polarity in many...
Bazooka/Par-3 (Baz) is an evolutionarily conserved scaffold protein that functions as a master regulator for the establishment and maintenance of cell polarity in many different cell types. In the vast majority of published research papers Baz has been reported to localize at the cell cortex and at intercellular junctions. However, there have also been several reports showing localization and function of Baz at additional subcellular sites, in particular the nuclear envelope and the neuromuscular junction. In this study we have re-assessed the localization of Baz to these subcellular sites in a systematic manner. We used antibodies raised in different host animals against different epitopes of Baz for confocal imaging of Drosophila tissues. We tested the specificity of these antisera by mosaic analysis with null mutant baz alleles and tissue-specific RNAi against baz. In addition, we used a GFP-tagged gene trap line for Baz and a bacterial artificial chromosome (BAC) expressing GFP-tagged Baz under control of its endogenous promoter in a baz mutant background to compare the subcellular localization of the GFP-Baz fusion proteins to the staining with anti-Baz antisera. Together, these experiments did not provide evidence for specific localization of Baz to the nucleus or the neuromuscular junction.
Topics: Animals; Cell Nucleus; Drosophila Proteins; Neuromuscular Junction; Protein Transport; Drosophila melanogaster
PubMed: 38841912
DOI: 10.1242/bio.060544 -
Nature Jun 2024Histone acetylation regulates gene expression, cell function and cell fate. Here we study the pattern of histone acetylation in the epithelial tissue of the Drosophila...
Histone acetylation regulates gene expression, cell function and cell fate. Here we study the pattern of histone acetylation in the epithelial tissue of the Drosophila wing disc. H3K18ac, H4K8ac and total lysine acetylation are increased in the outer rim of the disc. This acetylation pattern is controlled by nuclear position, whereby nuclei continuously move from apical to basal locations within the epithelium and exhibit high levels of H3K18ac when they are in proximity to the tissue surface. These surface nuclei have increased levels of acetyl-CoA synthase, which generates the acetyl-CoA for histone acetylation. The carbon source for histone acetylation in the rim is fatty acid β-oxidation, which is also increased in the rim. Inhibition of fatty acid β-oxidation causes H3K18ac levels to decrease in the genomic proximity of genes involved in disc development. In summary, there is a physical mark of the outer rim of the wing and other imaginal epithelia in Drosophila that affects gene expression.
Topics: Animals; Acetate-CoA Ligase; Acetyl Coenzyme A; Acetylation; Biological Transport; Cell Nucleus; Chromatin; Drosophila melanogaster; Drosophila Proteins; Fatty Acids; Gene Expression Regulation; Histones; Imaginal Discs; Lysine; Oxidation-Reduction; Wings, Animal
PubMed: 38839952
DOI: 10.1038/s41586-024-07471-4 -
Developmental and Comparative Immunology Sep 2024Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) that recognize invading pathogens and activate downstream signaling pathways. The number...
Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) that recognize invading pathogens and activate downstream signaling pathways. The number of 10 Tolls is found in Litopenaeus vannamei but have not yet been identified as the corresponding Toll homologue of model animal. In this study, we predicted the three-dimensional (3D) structures of 10 LvTolls (LvToll1-10) with AlphaFold2 program. The per-residue local distance difference test (pLDDT) scores of LvTolls showed the predicted structure of LvTolls had high accuracy (pLDDT>70). By structural analysis, 3D structures of LvToll2 and LvToll3 had high similarity with Drosophila melanogaster Toll and Toll7, respectively. 3D structure of LvToll7 and LvToll10 were not similar to that of other LvTolls. Moreover, we also predicted that LvSpätzle4 had high structural similarity to DmSpätzle. There were 9 potential hydrogen bonds in LvToll2-LvSpätzle4 complex. Importantly, co-immunoprecipitation assay showed that LvToll2 could bind with LvSpätzle4. Collectively, this study provides new insight for researching invertebrate immunity by identifying the protein of model animal homologue.
Topics: Animals; Penaeidae; Toll-Like Receptors; Drosophila melanogaster; Insect Proteins; Models, Molecular; Amino Acid Sequence; Immunity, Innate; Protein Binding; Phylogeny; Signal Transduction; Drosophila Proteins; Protein Conformation
PubMed: 38838948
DOI: 10.1016/j.dci.2024.105209 -
Proceedings of the National Academy of... Jun 2024Cytoplasmic mislocalization and aggregation of TDP-43 protein are hallmarks of amyotrophic lateral sclerosis (ALS) and are observed in the vast majority of both familial...
Cytoplasmic mislocalization and aggregation of TDP-43 protein are hallmarks of amyotrophic lateral sclerosis (ALS) and are observed in the vast majority of both familial and sporadic cases. How these two interconnected processes are regulated on a molecular level, however, remains enigmatic. Genome-wide screens for modifiers of the ALS-associated genes and have identified the phospholipase D (Pld) pathway as a key regulator of ALS-related phenotypes in the fruit fly [M. W. Kankel , Genetics , 747-766 (2020)]. Here, we report the results of our search for downstream targets of the enzymatic product of Pld, phosphatidic acid. We identify two conserved negative regulators of the cAMP/PKA signaling pathway, the phosphodiesterase and the inhibitory subunit , as modifiers of pathogenic phenotypes resulting from overexpression of the ortholog . We show that knockdown of either of these genes results in a mitigation of both TBPH aggregation and mislocalization in larval motor neuron cell bodies, as well as an amelioration of adult-onset motor defects and shortened lifespan induced by TBPH. We determine that PKA kinase activity is downstream of both TBPH and Pld and that overexpression of the PKA target CrebA can rescue TBPH mislocalization. These findings suggest a model whereby increasing cAMP/PKA signaling can ameliorate the molecular and functional effects of pathological TDP-43.
Topics: Animals; Cyclic AMP; Drosophila melanogaster; Cyclic AMP-Dependent Protein Kinases; Drosophila Proteins; Signal Transduction; DNA-Binding Proteins; Amyotrophic Lateral Sclerosis; Humans; Motor Neurons
PubMed: 38838021
DOI: 10.1073/pnas.2400732121 -
Lab Animal Jun 2024
Topics: Animals; Iron; Drosophila Proteins; Drosophila melanogaster; Drosophila
PubMed: 38834807
DOI: 10.1038/s41684-024-01386-3 -
Development (Cambridge, England) Jun 2024Germline maintenance relies on adult stem cells to continually replenish lost gametes over a lifetime and respond to external cues altering the demands on the tissue....
Germline maintenance relies on adult stem cells to continually replenish lost gametes over a lifetime and respond to external cues altering the demands on the tissue. Mating worsens germline homeostasis over time, yet a negative impact on stem cell behavior has not been explored. Using extended live imaging of the Drosophila testis stem cell niche, we find that short periods of mating in young males disrupts cytokinesis in germline stem cells (GSCs). This defect leads to failure of abscission, preventing release of differentiating cells from the niche. We find that GSC abscission failure is caused by increased Ecdysone hormone signaling induced upon mating, which leads to disrupted somatic encystment of the germline. Abscission failure is rescued by isolating males from females, but recurs with resumption of mating. Importantly, reiterative mating also leads to increased GSC loss, requiring increased restoration of stem cells via symmetric renewal and de-differentiation. Together, these results suggest a model whereby acute mating results in hormonal changes that negatively impact GSC cytokinesis but preserves the stem cell population.
Topics: Animals; Cytokinesis; Male; Ecdysone; Testis; Female; Drosophila melanogaster; Germ Cells; Stem Cell Niche; Stem Cells; Cell Differentiation; Signal Transduction; Drosophila Proteins
PubMed: 38832826
DOI: 10.1242/dev.202542