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Genetics Mar 2021The evolutionarily conserved Roundabout (Robo) family of axon guidance receptors control midline crossing of axons in response to the midline repellant ligand Slit in...
The evolutionarily conserved Roundabout (Robo) family of axon guidance receptors control midline crossing of axons in response to the midline repellant ligand Slit in bilaterian animals including insects, nematodes, and vertebrates. Despite this strong evolutionary conservation, it is unclear whether the signaling mechanism(s) downstream of Robo receptors are similarly conserved. To directly compare midline repulsive signaling in Robo family members from different species, here we use a transgenic approach to express the Robo family receptor SAX-3 from the nematode Caenorhabditis elegans in neurons of the fruit fly, Drosophila melanogaster. We examine SAX-3's ability to repel Drosophila axons from the Slit-expressing midline in gain of function assays, and test SAX-3's ability to substitute for Drosophila Robo1 during fly embryonic development in genetic rescue experiments. We show that C. elegans SAX-3 is properly translated and localized to neuronal axons when expressed in the Drosophila embryonic CNS, and that SAX-3 can signal midline repulsion in Drosophila embryonic neurons, although not as efficiently as Drosophila Robo1. Using a series of Robo1/SAX-3 chimeras, we show that the SAX-3 cytoplasmic domain can signal midline repulsion to the same extent as Robo1 when combined with the Robo1 ectodomain. We show that SAX-3 is not subject to endosomal sorting by the negative regulator Commissureless (Comm) in Drosophila neurons in vivo, and that peri-membrane and ectodomain sequences are both required for Comm sorting of Drosophila Robo1.
Topics: Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Conserved Sequence; Drosophila Proteins; Drosophila melanogaster; Endosomes; Evolution, Molecular; Genetic Complementation Test; Membrane Proteins; Nerve Tissue Proteins; Neurons; Protein Transport; Receptors, Immunologic; Signal Transduction; Roundabout Proteins
PubMed: 33789352
DOI: 10.1093/genetics/iyab018 -
Aging Aug 2022Since interventions such as caloric restriction or fasting robustly promote lipid catabolism and improve aging-related phenotypical markers, we investigated the direct...
Since interventions such as caloric restriction or fasting robustly promote lipid catabolism and improve aging-related phenotypical markers, we investigated the direct effect of increased lipid catabolism via overexpression of (, FBgn0036449), the major triglyceride hydrolase in on lifespan and physiological fitness. Comprehensive characterization was carried out using RNA-seq, lipidomics and metabolomics analysis. Global overexpression of strongly promoted numerous markers of physiological fitness, including increased female fecundity, fertility maintenance, preserved locomotion activity, increased mitochondrial biogenesis and oxidative metabolism. Increased robustly upregulated the heat shock protein 70 (Hsp70) family of proteins, which equipped the flies with higher resistance to heat, cold, and ER stress via improved proteostasis. Despite improved physiological fitness, overexpression did not extend lifespan. Taken together, these data show that overexpression has broad beneficial effects on physiological fitness, but these effects did not impact lifespan.
Topics: Animals; Drosophila; Drosophila Proteins; Drosophila melanogaster; Female; Lipolysis; Longevity; Triglycerides
PubMed: 36044277
DOI: 10.18632/aging.204251 -
Current Opinion in Insect Science Apr 2022Germ plasm is a substance capable of driving naive cells toward the germ cell fate. Germ plasm has had multiple independent origins, and takes on diverse forms and... (Review)
Review
Germ plasm is a substance capable of driving naive cells toward the germ cell fate. Germ plasm has had multiple independent origins, and takes on diverse forms and functions throughout animals, including in insects. We describe here recent advances in the understanding of the evolution of germ plasm in insects. A major theme that has emerged is the complex and convoluted interactions of germ plasm with symbiotic bacteria within the germline, including at the very origin of oskar, the gene required for assembling germ plasm in insects. Major advancements have also been made in understanding the basic molecular arrangement of germ plasm in insects. These advances demonstrate that further analysis of insect germ plasm will be fruitful in illuminating diverse aspects of evolutionary and developmental biology.
Topics: Animals; Drosophila Proteins; Germ Cells; Insecta
PubMed: 35123121
DOI: 10.1016/j.cois.2022.100883 -
Current Topics in Developmental Biology 2023Actin networks are central to shaping and moving cells during animal development. Various spatial cues activate conserved signal transduction pathways to polarize actin... (Review)
Review
Actin networks are central to shaping and moving cells during animal development. Various spatial cues activate conserved signal transduction pathways to polarize actin network assembly at sub-cellular locations and to elicit specific physical changes. Actomyosin networks contract and Arp2/3 networks expand, and to affect whole cells and tissues they do so within higher-order systems. At the scale of tissues, actomyosin networks of epithelial cells can be coupled via adherens junctions to form supracellular networks. Arp2/3 networks typically integrate with distinct actin assemblies, forming expansive composites which act in conjunction with contractile actomyosin networks for whole-cell effects. This review explores these concepts using examples from Drosophila development. First, we discuss the polarized assembly of supracellular actomyosin cables which constrict and reshape epithelial tissues during embryonic wound healing, germ band extension, and mesoderm invagination, but which also form physical borders between tissue compartments at parasegment boundaries and during dorsal closure. Second, we review how locally induced Arp2/3 networks act in opposition to actomyosin structures during myoblast cell-cell fusion and cortical compartmentalization of the syncytial embryo, and how Arp2/3 and actomyosin networks also cooperate for the single cell migration of hemocytes and the collective migration of border cells. Overall, these examples show how the polarized deployment and higher-order interactions of actin networks organize developmental cell biology.
Topics: Animals; Actins; Drosophila; Actomyosin; Drosophila Proteins; Muscle Contraction; Drosophila melanogaster
PubMed: 37100525
DOI: 10.1016/bs.ctdb.2023.02.005 -
ENeuro 2022Ten-eleven translocation (TET) proteins are crucial epigenetic regulators highly conserved in multicellular organisms. TETs' enzymatic function in demethylating 5-methyl...
Ten-eleven translocation (TET) proteins are crucial epigenetic regulators highly conserved in multicellular organisms. TETs' enzymatic function in demethylating 5-methyl cytosine in DNA is required for proper development and TETs are frequently mutated in cancer. Recently, Tet (dTet) was shown to be highly expressed in developing fly brains and discovered to play an important role in brain and muscle development as well as fly behavior. Furthermore, dTet was shown to have different substrate specificity compared with mammals. However, the exact role dTet plays in glial cells and how ectopic TET expression in glial cells contributes to tumorigenesis and glioma is still not clear. Here, we report a novel role for dTet specifically in glial cell organization and number. We show that loss of dTet affects the organization of a specific glia population in the optic lobe, the "optic chiasm" glia. Additionally, we find irregularities in axon patterns in the ventral nerve cord (VNC) both, in the midline and longitudinal axons. These morphologic glia and axonal defects were accompanied by locomotor defects in developing larvae escalating to immobility in adult flies. Furthermore, glia homeostasis was disturbed in dTet-deficient brains manifesting in gain of glial cell numbers and increased proliferation. Finally, we establish a model to understand the impact of human TET3 in glia and find that ectopic expression of hTET3 in dTet-expressing cells causes glia expansion in larval brains and affects sleep/rest behavior and the circadian clock in adult flies.
Topics: Animals; Brain; Drosophila; Drosophila Proteins; Drosophila melanogaster; Homeostasis; Larva; Mammals; Neuroglia
PubMed: 35396259
DOI: 10.1523/ENEURO.0418-21.2022 -
Science Signaling Jul 2023During cytokinesis, the cell membrane furrows inward along a cleavage plane. The positioning of the cleavage plane is critical to faithful cell division and is...
During cytokinesis, the cell membrane furrows inward along a cleavage plane. The positioning of the cleavage plane is critical to faithful cell division and is determined by the Rho guanine nucleotide exchange factor (RhoGEF)-mediated activation of the small guanosine triphosphatase RhoA and the conserved motor protein complex centralspindlin. Here, we explored whether and how centralspindlin mediates the positioning of RhoGEF. In dividing neuroblasts from , we observed that immediately before cleavage, first centralspindlin and then RhoGEF localized to the sites where cleavage subsequently initiated. Using in vitro assays with purified proteins and stabilized microtubules, we found that centralspindlin directly transported RhoGEF as cargo along single microtubules and sequestered it at microtubule plus-ends for prolonged periods of time. In addition, the binding of RhoGEF to centralspindlin appeared to stimulate centralspindlin motor activity. Thus, the motor activity and microtubule association of centralspindlin can translocate RhoGEF to areas where microtubule plus-ends are abundant, such as at overlapping astral microtubules, to locally activate RhoA and accurately position the cleavage plane during cell division.
Topics: Animals; Cytokinesis; Drosophila melanogaster; Microtubules; Drosophila Proteins; Rho Guanine Nucleotide Exchange Factors; Spindle Apparatus
PubMed: 37402224
DOI: 10.1126/scisignal.adh0601 -
BioEssays : News and Reviews in... Sep 2023Secreted signaling molecules act as morphogens to control patterning and growth in many developing tissues. Since locally produced morphogens spread to form a... (Review)
Review
Secreted signaling molecules act as morphogens to control patterning and growth in many developing tissues. Since locally produced morphogens spread to form a concentration gradient in the surrounding tissue, spreading is generally thought to be the key step in the non-autonomous actions. Here, we review recent advances in tool development to investigate morphogen function using the role of decapentaplegic (Dpp)/bone morphogenetic protein (BMP)-type ligand in the Drosophila wing disc as an example. By applying protein binder tools to distinguish between the roles of Dpp spreading and local Dpp signaling, we found that Dpp signaling in the source cells is important for wing patterning and growth but Dpp spreading from this source cells is not as strictly required as previously thought. Given recent studies showing unexpected requirements of long-range action of different morphogens, manipulating endogenous morphogen gradients by synthetic protein binder tools could shed more light on how morphogens act in developing tissues.
Topics: Animals; Body Patterning; Drosophila; Drosophila melanogaster; Drosophila Proteins; Gene Expression Regulation, Developmental
PubMed: 37452394
DOI: 10.1002/bies.202200218 -
Neural Development Oct 2022The paths axons travel to reach their targets and the subsequent synaptic connections they form are highly stereotyped. How cell surface proteins (CSPs) mediate these...
The paths axons travel to reach their targets and the subsequent synaptic connections they form are highly stereotyped. How cell surface proteins (CSPs) mediate these processes is not completely understood. The Drosophila neuromuscular junction (NMJ) is an ideal system to study how pathfinding and target specificity are accomplished, as the axon trajectories and innervation patterns are known and easily visualized. Dpr10 is a CSP required for synaptic partner choice in the neuromuscular and visual circuits and for axon pathfinding in olfactory neuron organization. In this study, we show that Dpr10 is also required for motor axon pathfinding. To uncover how Dpr10 mediates this process, we used immunoprecipitation followed by mass spectrometry to identify Dpr10 associated proteins. One of these, Nocte, is an unstructured, intracellular protein implicated in circadian rhythm entrainment. We mapped nocte expression in larvae and found it widely expressed in neurons, muscles, and glia. Cell-specific knockdown suggests nocte is required presynaptically to mediate motor axon pathfinding. Additionally, we found that nocte and dpr10 genetically interact to control NMJ assembly, suggesting that they function in the same molecular pathway. Overall, these data reveal novel roles for Dpr10 and its newly identified interactor, Nocte, in motor axon pathfinding and provide insight into how CSPs regulate circuit assembly.
Topics: Animals; Drosophila; Axon Guidance; Motor Neurons; Axons; Drosophila Proteins; Membrane Proteins
PubMed: 36271407
DOI: 10.1186/s13064-022-00165-5 -
Molecular Biology and Evolution Aug 2019Understanding the molecular basis of hybrid incompatibilities is a fundamental pursuit in evolutionary genetics. In crosses between Drosophila melanogaster females and...
Understanding the molecular basis of hybrid incompatibilities is a fundamental pursuit in evolutionary genetics. In crosses between Drosophila melanogaster females and Drosophila simulans males, an interaction between at least three genes is necessary for hybrid male lethality: Hmr mel, Lhr sim, and gfzf sim. Although HMR and LHR physically bind each other and function together in a single complex, the connection between gfzf and either of these proteins remains mysterious. Here, we show that GFZF localizes to many regions of the genome in both D. melanogaster and D. simulans, including at telomeric retrotransposon repeats. We find that GFZF localization at telomeres is significantly different between these two species, reflecting the rapid evolution of telomeric retrotransposon copy number composition between the two species. Next, we show that GFZF and HMR normally do not colocalize in D. melanogaster. In interspecies hybrids, however, HMR shows extensive mis-localization to GFZF sites, thus uncovering a new molecular interaction between these hybrid incompatibility factors. We find that spreading of HMR to GFZF sites requires gfzf sim but not Lhr sim, suggesting distinct roles for these factors in the hybrid incompatibility. Finally, we find that overexpression of HMR and LHR within species is sufficient to mis-localize HMR to GFZF binding sites, indicating that HMR has a natural low affinity for GFZF sites. Together, these studies provide the first insights into the different properties of gfzf between D. melanogaster and D. simulans, and uncover a molecular interaction between gfzf and Hmr in the form of altered protein localization.
Topics: Animals; Carrier Proteins; Drosophila; Drosophila Proteins; Female; Hybridization, Genetic; Male; Reproductive Isolation
PubMed: 31038678
DOI: 10.1093/molbev/msz105 -
Epigenetics Nov 2020Ten-eleven Translocation (TET) proteins have emerged as a family of epigenetic regulators that are important during development and have been implicated in various types... (Review)
Review
Ten-eleven Translocation (TET) proteins have emerged as a family of epigenetic regulators that are important during development and have been implicated in various types of cancers. TET is a highly conserved protein that has orthologues in almost all multicellular organisms. Here, we review recent literature on the novel substrate specificity of this family of DNA 5-methylcytosine demethylases on DNA 6-methyladenine and RNA 5-methylcytosine that were first identified in the invertebrate model . We focus on the biological role of these novel epigenetic marks in the fruit fly and mammals and highlight TET proteins' critical function during development specifically in brain development.
Topics: Animals; DNA Methylation; Drosophila; Drosophila Proteins; Epigenesis, Genetic; Gene Expression Regulation, Developmental; Mixed Function Oxygenases
PubMed: 32419604
DOI: 10.1080/15592294.2020.1767323