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Journal of Hazardous Materials Mar 2024The discernment and aversion of noxious gustatory stimuli profoundly influence homeostasis maintenance and survival of fauna. Cantharidin, a purported aphrodisiac, is a...
The discernment and aversion of noxious gustatory stimuli profoundly influence homeostasis maintenance and survival of fauna. Cantharidin, a purported aphrodisiac, is a monoterpenoid compound secreted by many species of blister beetle, particularly by the Spanish fly, Lytta vesicatoria. Although the various advantageous functions of cantharidin have been described, its taste analysis and toxic properties in animalshave been rarely explored. Our study using Drosophila melanogaster examines the taste properties of cantharidin along with its potential hazardous effect in the internal organs of animals. Here, we find that cantharidin activates bitter taste receptors. Our findings show that specific ionotropic receptors (IR7g, IR51b, and IR94f) in labellar bitter-sensing neurons, along with co-receptors IR25a and IR76b, are responsible for detecting cantharidin. By introducing the IR7g and IR51b in sweet and bitter neurons, naturally expressing IR76b and IR25a, we show that these genes are sufficient for cantharidin perception. Moreover, we witness the deleterious ramifications of cantharidin on survival and visceral integrities, shedding light on its hazardous effect.
Topics: Animals; Drosophila melanogaster; Drosophila Proteins; Cantharidin; Taste; Taste Perception
PubMed: 38278077
DOI: 10.1016/j.jhazmat.2024.133497 -
The Journal of Cell Biology Oct 2023PIWI-interacting RNAs (piRNAs), which protect genome from the attack by transposons, are produced and amplified in membraneless granules called nuage. In Drosophila,...
PIWI-interacting RNAs (piRNAs), which protect genome from the attack by transposons, are produced and amplified in membraneless granules called nuage. In Drosophila, PIWI family proteins, Tudor-domain-containing (Tdrd) proteins, and RNA helicases are assembled and form nuage to ensure piRNA production. However, the molecular functions of the Tdrd protein Tejas (Tej) in piRNA biogenesis remain unknown. Here, we conduct a detailed analysis of the subcellular localization of fluorescently tagged nuage proteins and behavior of piRNA precursors. Our results demonstrate that Tej functions as a core component that recruits Vasa (Vas) and Spindle-E (Spn-E) into nuage granules through distinct motifs, thereby assembling nuage and engaging precursors for further processing. Our study also reveals that the low-complexity region of Tej regulates the mobility of Vas. Based on these results, we propose that Tej plays a pivotal role in piRNA precursor processing by assembling Vas and Spn-E into nuage and modulating the mobility of nuage components.
Topics: Animals; Drosophila melanogaster; Drosophila Proteins; Piwi-Interacting RNA; DEAD-box RNA Helicases; Adenosine Triphosphatases
PubMed: 37555815
DOI: 10.1083/jcb.202303125 -
Developmental Cell Oct 2023The steroid hormone 20-hydroxy-ecdysone (20E) promotes proliferation in Drosophila wing precursors at low titer but triggers proliferation arrest at high doses....
The steroid hormone 20-hydroxy-ecdysone (20E) promotes proliferation in Drosophila wing precursors at low titer but triggers proliferation arrest at high doses. Remarkably, wing precursors proliferate normally in the complete absence of the 20E receptor, suggesting that low-level 20E promotes proliferation by overriding the default anti-proliferative activity of the receptor. By contrast, 20E needs its receptor to arrest proliferation. Dose-response RNA sequencing (RNA-seq) analysis of ex vivo cultured wing precursors identifies genes that are quantitatively activated by 20E across the physiological range, likely comprising positive modulators of proliferation and other genes that are only activated at high doses. We suggest that some of these "high-threshold" genes dominantly suppress the activity of the pro-proliferation genes. We then show mathematically and with synthetic reporters that combinations of basic regulatory elements can recapitulate the behavior of both types of target genes. Thus, a relatively simple genetic circuit can account for the bimodal activity of this hormone.
Topics: Animals; Drosophila; Drosophila Proteins; Ligands; Receptors, Steroid; Hormones; Cell Proliferation; Ecdysone
PubMed: 37769663
DOI: 10.1016/j.devcel.2023.08.032 -
Journal of Visualized Experiments : JoVE Oct 2023The microtubule network is an essential component of the nervous system. Mutations in many microtubules regulatory proteins are associated with neurodevelopmental...
The microtubule network is an essential component of the nervous system. Mutations in many microtubules regulatory proteins are associated with neurodevelopmental disorders and neurological diseases, such as microtubule-associated protein Tau to neurodegenerative diseases, microtubule severing protein Spastin and Katanin 60 cause hereditary spastic paraplegia and neurodevelopmental abnormalities, respectively. Detection of microtubule networks in neurons is advantageous for elucidating the pathogenesis of neurological disorders. However, the small size of neurons and the dense arrangement of axonal microtubule bundles make visualizing the microtubule networks challenging. In this study, we describe a method for dissection of the larval neuromuscular junction and muscle cells, as well as immunostaining of α-tubulin and microtubule-associated protein Futsch to visualize microtubule networks in Drosophila melanogaster. The neuromuscular junction permits us to observe both pre-and post-synaptic microtubules, and the large size of muscle cells in Drosophila larva allows for clear visualization of the microtubule network. Here, by mutating and overexpressing Katanin 60 in Drosophila melanogaster, and then examining the microtubule networks in the neuromuscular junction and muscle cells, we accurately reveal the regulatory role of Katanin 60 in neurodevelopment. Therefore, combined with the powerful genetic tools of Drosophila melanogaster, this protocol greatly facilitates genetic screening and microtubule dynamics analysis for the role of microtubule network regulatory proteins in the nervous system.
Topics: Animals; Drosophila; Drosophila melanogaster; Katanin; Larva; Drosophila Proteins; Microtubules; Neuromuscular Junction; Muscle Cells
PubMed: 37929978
DOI: 10.3791/65774 -
Proteins Jun 2024Understanding the emergence and structural characteristics of de novo and random proteins is crucial for unraveling protein evolution and designing novel enzymes....
Understanding the emergence and structural characteristics of de novo and random proteins is crucial for unraveling protein evolution and designing novel enzymes. However, experimental determination of their structures remains challenging. Recent advancements in protein structure prediction, particularly with AlphaFold2 (AF2), have expanded our knowledge of protein structures, but their applicability to de novo and random proteins is unclear. In this study, we investigate the structural predictions and confidence scores of AF2 and protein language model-based predictor ESMFold for de novo and conserved proteins from Drosophila and a dataset of comparable random proteins. We find that the structural predictions for de novo and random proteins differ significantly from conserved proteins. Interestingly, a positive correlation between disorder and confidence scores (pLDDT) is observed for de novo and random proteins, in contrast to the negative correlation observed for conserved proteins. Furthermore, the performance of structure predictors for de novo and random proteins is hampered by the lack of sequence identity. We also observe fluctuating median predicted disorder among different sequence length quartiles for random proteins, suggesting an influence of sequence length on disorder predictions. In conclusion, while structure predictors provide initial insights into the structural composition of de novo and random proteins, their accuracy and applicability to such proteins remain limited. Experimental determination of their structures is necessary for a comprehensive understanding. The positive correlation between disorder and pLDDT could imply a potential for conditional folding and transient binding interactions of de novo and random proteins.
Topics: Animals; Protein Folding; Conserved Sequence; Drosophila Proteins; Databases, Protein; Models, Molecular; Computational Biology; Proteins; Intrinsically Disordered Proteins; Protein Conformation; Amino Acid Sequence; Algorithms; Drosophila
PubMed: 38226524
DOI: 10.1002/prot.26652 -
Developmental Cell Nov 2023In multicellular lives, the differentiation of stem cells and progenitor cells is often accompanied by a transition from glycolysis to mitochondrial oxidative...
In multicellular lives, the differentiation of stem cells and progenitor cells is often accompanied by a transition from glycolysis to mitochondrial oxidative phosphorylation (OXPHOS). However, the underlying mechanism of this metabolic transition remains largely unknown. In this study, we investigate the role of mechanical stress in activating OXPHOS during differentiation of the female germline cyst in Drosophila. We demonstrate that the surrounding somatic cells flatten the 16-cell differentiating cyst, resulting in an increase of the membrane tension of germ cells inside the cyst. This mechanical stress is necessary to maintain cytosolic Ca concentration in germ cells through a mechanically activated channel, transmembrane channel-like. The sustained cytosolic Ca triggers a CaMKI-Fray-JNK signaling relay, leading to the transcriptional activation of OXPHOS in differentiating cysts. Our findings demonstrate a molecular link between cell mechanics and mitochondrial energy metabolism, with implications for other developmentally orchestrated metabolic transitions in mammals.
Topics: Animals; Drosophila; Germ Cells; Energy Metabolism; Cell Differentiation; Drosophila Proteins; Mammals
PubMed: 37647895
DOI: 10.1016/j.devcel.2023.08.007 -
Current Biology : CB Dec 2023The mechanisms underlying the construction of an air-liquid interface in respiratory organs remain elusive. Here, we use live imaging and genetic analysis to describe...
The mechanisms underlying the construction of an air-liquid interface in respiratory organs remain elusive. Here, we use live imaging and genetic analysis to describe the morphogenetic events generating an extracellular lipid lining of the Drosophila airways required for their gas filing and animal survival. We show that sequential Rab39/Syx1A/Syt1-mediated secretion of lysosomal acid sphingomyelinase (Drosophila ASM [dASM]) and Rab11/35/Syx1A/Rop-dependent exosomal secretion provides distinct components for lipid film assembly. Tracheal inactivation of Rab11 or Rab35 or loss of Rop results in intracellular accumulation of exosomal, multi-vesicular body (MVB)-derived vesicles. On the other hand, loss of dASM or Rab39 causes luminal bubble-like accumulations of exosomal membranes and liquid retention in the airways. Inactivation of the exosomal secretion in dASM mutants counteracts this phenotype, arguing that the exosomal secretion provides the lipid vesicles and that secreted lysosomal dASM organizes them into a continuous film. Our results reveal the coordinated functions of extracellular vesicle and lysosomal secretions in generating a lipid layer crucial for airway gas filling and survival.
Topics: Animals; Drosophila; Surface-Active Agents; Endosomes; Trachea; Lipids; Nerve Tissue Proteins; Drosophila Proteins
PubMed: 37992718
DOI: 10.1016/j.cub.2023.10.058 -
Current Biology : CB Aug 2023Bilateral symmetry defines much of the animal kingdom and is crucial for numerous functions of bilaterian organisms. Genetic approaches have discovered highly conserved...
Bilateral symmetry defines much of the animal kingdom and is crucial for numerous functions of bilaterian organisms. Genetic approaches have discovered highly conserved patterning networks that establish bilateral symmetry in early embryos, but how this symmetry is maintained throughout subsequent morphogenetic events remains largely unknown. Here we show that the terminal patterning system-which relies on Ras/ERK signaling through activation of the Torso receptor by its ligand Trunk-is critical for preserving bilateral symmetry during Drosophila body axis elongation, a process driven by cell rearrangements in the two identical lateral regions of the embryo and specified by the dorsal-ventral and anterior-posterior patterning systems. We demonstrate that fluctuating asymmetries in this rapid convergent-extension process are attenuated in normal embryos over time, possibly through noise-dissipating forces from the posterior midgut invagination and movement. However, when Torso signaling is attenuated via mutation of Trunk or RNAi directed against downstream Ras/ERK pathway components, body axis elongation results in a characteristic corkscrew phenotype, which reflects dramatic reorganization of global tissue flow and is incompatible with viability. Our results reveal a new function downstream of the Drosophila terminal patterning system in potentially active control of bilateral symmetry and should motivate systematic search for similar symmetry-preserving regulatory mechanisms in other bilaterians.
Topics: Animals; Body Patterning; Morphogenesis; Drosophila; Drosophila Proteins; Gastrulation; Gene Expression Regulation, Developmental; Embryo, Nonmammalian
PubMed: 37562404
DOI: 10.1016/j.cub.2023.07.050 -
Results and Problems in Cell... 2024The Drosophila trachea is an interconnected network of epithelial tubes, which delivers gases throughout the entire organism. It is the premier model to study the... (Review)
Review
The Drosophila trachea is an interconnected network of epithelial tubes, which delivers gases throughout the entire organism. It is the premier model to study the development of tubular organs, such as the human lung, kidney, and blood vessels. The Drosophila embryonic trachea derives from a series of segmentally repeated clusters. The tracheal precursor cells in each cluster migrate out in a stereotyped pattern to form primary branches. Thereafter, the neighboring branches need to fuse to form an interconnected tubular network. The connection between neighboring branches is orchestrated by specialized cells, called fusion cells. These cells fuse with their counterparts to form a tube with a contiguous lumen. Branch fusion is a multi-step process that includes cell migration, cell adhesion, cytoskeleton track formation, vesicle trafficking, membrane fusion, and lumen formation. This review summarizes the current knowledge on fusion process in the Drosophila trachea. These mechanisms will greatly contribute to our understanding of branch fusion in mammalian systems.
Topics: Animals; Cytoskeleton; Drosophila; Drosophila melanogaster; Drosophila Proteins; Mammals; Microtubules; Morphogenesis; Trachea
PubMed: 37996674
DOI: 10.1007/978-3-031-37936-9_5 -
Biological Research Sep 2023The endoplasmic reticulum (ER) contacts endosomes in all parts of a motor neuron, including the axon and presynaptic terminal, to move structural proteins, proteins that...
BACKGROUND
The endoplasmic reticulum (ER) contacts endosomes in all parts of a motor neuron, including the axon and presynaptic terminal, to move structural proteins, proteins that send signals, and lipids over long distances. Atlastin (Atl), a large GTPase, is required for membrane fusion and the structural dynamics of the ER tubules. Atl mutations are the second most common cause of Hereditary Spastic Paraplegia (HSP), which causes spasticity in both sexes' lower extremities. Through an unknown mechanism, Atl mutations stimulate the BMP (bone morphogenetic protein) pathway in vertebrates and Drosophila. Synaptic defects are caused by atl mutations, which affect the abundance and distribution of synaptic vesicles (SV) in the bouton. We hypothesize that BMP signaling, does not cause Atl-dependent SV abnormalities in Drosophila.
RESULTS
We show that atl knockdown in motor neurons (Atl-KD) increases synaptic and satellite boutons in the same way that constitutively activating the BMP-receptor Tkv (thick veins) (Tkv-CA) increases the bouton number. The SV proteins Cysteine string protein (CSP) and glutamate vesicular transporter are reduced in Atl-KD and Tkv-CA larvae. Reducing the activity of the BMP receptor Wishful thinking (wit) can rescue both phenotypes. Unlike Tkv-CA larvae, Atl-KD larvae display altered activity-dependent distributions of CSP staining. Furthermore, Atl-KD larvae display an increased FM 1-43 unload than Control and Tkv-CA larvae. As decreasing wit function does not reduce the phenotype, our hypothesis that BMP signaling is not involved is supported. We also found that Rab11/CSP colocalization increased in Atl-KD larvae, which supports the concept that late recycling endosomes regulate SV movements.
CONCLUSIONS
Our findings reveal that Atl modulates neurotransmitter release in motor neurons via SV distribution independently of BMP signaling, which could explain the observed SV accumulation and synaptic dysfunction. Our data suggest that Atl is involved in membrane traffic as well as formation and/or recycling of the late endosome.
Topics: Animals; Female; Male; Biological Transport; Drosophila; Drosophila Proteins; Receptors, Cell Surface; Synaptic Transmission; Synaptic Vesicles
PubMed: 37710314
DOI: 10.1186/s40659-023-00462-1