scholarly journals A shotgun approach to identify mechanical nociception genes

2016 ◽  
Author(s):  
Melissa G. Christianson ◽  
Stephanie E. Mauthner ◽  
W. Daniel Tracey
Keyword(s):  
Drosophila Melanogaster ◽  
Sensory Neurons ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Single Gene ◽  
Behavioral Responses ◽  
Genetic Screen ◽  
Genetic Screens ◽  
Behavioral Testing ◽  
Shotgun Approach

AbstractThe molecular mechanisms of sensing noxious mechanical force by nociceptive sensory neurons remain poorly understood. Traditional methods for probing mechanical nociception behavioral responses are labor intensive and involve the testing of one animal at a time. This time consuming process of behavioral testing has largely precluded large scale analyses. Indeed, large scale genetic screens that have been performed thus far have been largely restricted to the investigation of ion channel genes [1]. Here we describe a new behavioral assay for mechanical nociception in which tens of animals can be stimulated simultaneously. In this assay, third instar larvae of the genetically tractable organism Drosophila melanogaster are mechanically stimulated with tungsten particles that are fired from a gun. We have used the new assay to carry out a genetic screen in which we investigated the function of 231 nociceptor enriched genes with tissue-specific RNA interference. Targeting of 21 genes resulted in mechanically insensitive phenotypes and targeting of a single gene resulted in a hypersensitive mechanical nociception phenotype. Six of the identified genes were previously uncharacterized and these were named after famed Roman gladiators (Spartacus (CG14186), Commodus (CG1311), Flamma (CG10914), Crixus(CG6685), Spiculus (CG10932), and Verus (CG31324)).

scholarly journals NETWORKS FROM GENE EXPRESSION TIME SERIES: CHARACTERIZATION OF CORRELATION PATTERNS

2007 ◽  
Vol 17 (07) ◽  
pp. 2477-2483 ◽  
Author(s):  
D. REMONDINI ◽  
N. NERETTI ◽  
C. FRANCESCHI ◽  
P. TIERI ◽  
J. M. SEDIVY ◽  
...  
Keyword(s):  
Gene Expression ◽  
Time Series ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Single Gene ◽  
Biological Information ◽  
Reconstruction Method ◽  
Gene Expression Time Series ◽  
Expression Time

We address the problem of finding large-scale functional and structural relationships between genes, given a time series of gene expression data, namely mRNA concentration values measured from genetically engineered rat fibroblasts cell lines responding to conditional cMyc proto-oncogene activation. We show how it is possible to retrieve suitable information about molecular mechanisms governing the cell response to conditional perturbations. This task is complex because typical high-throughput genomics experiments are performed with high number of probesets (103–104 genes) and a limited number of observations (< 102 time points). In this paper, we develop a deepest analysis of our previous work [Remondini et al., 2005] in which we characterized some of the main features of a gene-gene interaction network reconstructed from temporal correlation of gene expression time series. One first advancement is based on the comparison of the reconstructed network with networks obtained from randomly generated data, in order to characterize which features retrieve real biological information, and which are instead due to the characteristics of the network reconstruction method. The second and perhaps more relevant advancement is the characterization of the global change in co-expression pattern following cMyc activation as compared to a basal unperturbed state. We propose an analogy with a physical system in a critical state close to a phase transition (e.g. Potts ferromagnet), since the cell responds to the stimulus with high susceptibility, such that a single gene activation propagates to almost the entire genome. Our result is relative to temporal properties of gene network dynamics, and there are experimental evidence that this can be related to spatial properties regarding the global organization of chromatine structure [Knoepfler et al., 2006].

scholarly journals Genetic Screens to Analyze Pattern Formation of Egg and Embryo in Drosophila: A Personal History

2019 ◽  
Vol 53 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Trudi Schüpbach
Keyword(s):  
Pattern Formation ◽  
Large Scale ◽  
Genetic Screen ◽  
Personal History ◽  
Follicle Cells ◽  
Axis Formation ◽  
Molecular Pathways ◽  
Genetic Screens ◽  
Pattern Information ◽  
Anterior Posterior

In Drosophila development, the axes of the egg and future embryo are established during oogenesis. To learn about the underlying genetic and molecular pathways that lead to axis formation, I conducted a large-scale genetic screen at the beginning of my independent career. This led to the eventual understanding that both anterior-posterior and dorsal-ventral pattern information is transmitted from the oocyte to the surrounding follicle cells and in turn from the follicle cells back to the oocyte. How I came to conduct this screen and what further insights were gained by studying the mutants isolated in the screen are the topics of this autobiographical article.

scholarly journals Redundant neural circuits regulate olfactory masking

2021 ◽  
Author(s):  
Wenxing Yang ◽  
Taihong Wu ◽  
Shasha Tu ◽  
Myung-Kyu Choi ◽  
Fengyun Duan ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Neural Circuits ◽  
Critical Role ◽  
Behavioral Responses ◽  
Isoamyl Alcohol ◽  
Structure And Function ◽  
Genetic Screen ◽  
Masking Effect ◽  
Forward Genetic Screen ◽  
And Function

Olfactory masking is a complex olfactory response found in humans. However, the mechanisms whereby the presence of one odorant masks the sensory and behavioral responses elicited by another odorant are poorly understood. Here, we report that Caenorhabditis elegans displays olfactory masking and that the presence of a repulsive odorant, 2-nonanone, that signals threat strongly masks the attraction of other odorants, such as isoamyl alcohol (IAA) or benzaldehyde that signals food. Using a forward genetic screen, we found that several genes, osm-5, osm-1, and dyf-7, known to regulate the structure and function of sensory neurons played a critical role in olfactory masking. Loss of these genes mildly reduces the response to 2-nonanone and disrupts the masking effect of 2-nonanone. Restoring the function of OSM-5 in either AWB or ASH, two sensory neurons known to mediate 2-nonanone-evoked avoidance, is sufficient to rescue olfactory masking. AWB is activated by the removal of 2-nonanone stimulation or the onset of IAA; however, the mixture of 2-nonanone and IAA stimulates AWB similarly as 2-nonanone alone, masking the cellular effect of IAA. The latency of the AWB response is critical for the masking effect. Thus, our results identify redundant neural circuits that regulate the robust masking effect of a repulsive odorant and uncover the neuronal and cellular basis for this complex olfactory task.

Genetic Modifier Screens in Drosophila Demonstrate a Role for Rho1 Signaling in Ecdysone-Triggered Imaginal Disc Morphogenesis

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1397-1415 ◽  
Author(s):  
Robert E Ward ◽  
Janelle Evans ◽  
Carl S Thummel
Keyword(s):  
Imaginal Disc ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Genetic Interaction ◽  
Genetic Modifier ◽  
Early Gene ◽  
Genetic Screens ◽  
Major Transitions ◽  
Candidate Mutation ◽  
Ideal Model System

Abstract Drosophila adult leg development provides an ideal model system for characterizing the molecular mechanisms of hormone-triggered morphogenesis. A pulse of the steroid hormone ecdysone at the onset of metamorphosis triggers the rapid transformation of a flat leg imaginal disc into an immature adult leg, largely through coordinated changes in cell shape. In an effort to identify links between the ecdysone signal and the cytoskeletal changes required for leg morphogenesis, we performed two large-scale genetic screens for dominant enhancers of the malformed leg phenotype associated with a mutation in the ecdysoneinducible broad early gene (br1). From a screen of &gt;750 independent deficiency and candidate mutation stocks, we identified 17 loci on the autosomes that interact strongly with br1. In a complementary screen of ∼112,000 F1 progeny of EMS-treated br1 animals, we recovered 26 mutations that enhance the br1 leg phenotype [E(br) mutations]. Rho1, stubbloid, blistered (DSRF), and cytoplasmic Tropomyosin were identified from these screens as br1-interacting genes. Our findings suggest that ecdysone exerts its effects on leg morphogenesis through a Rho1 signaling cascade, a proposal that is supported by genetic interaction studies between the E(br) mutations and mutations in the Rho1 signaling pathway. In addition, several E(br) mutations produce unexpected defects in midembryonic morphogenetic movements. Coupled with recent evidence implicating ecdysone signaling in these embryonic morphogenetic events, our results suggest that a common ecdysone-dependent, Rho1-mediated regulatory pathway controls morphogenesis during the two major transitions in the life cycle, embryogenesis and metamorphosis.

scholarly journals EGCG binds intrinsically disordered N-terminal domain of p53 and disrupts p53-MDM2 interaction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Zhao ◽  
Alan Blayney ◽  
Xiaorong Liu ◽  
Lauren Gandy ◽  
Weihua Jin ◽  
...  
Keyword(s):  
Large Scale ◽  
Molecular Mechanisms ◽  
Epigallocatechin Gallate ◽  
Cancer Drug ◽  
Dynamic Interactions ◽  
Cancer Drug Discovery ◽  
Intrinsically Disordered ◽  
Terminal Domain ◽  
Cancerous Cells

AbstractEpigallocatechin gallate (EGCG) from green tea can induce apoptosis in cancerous cells, but the underlying molecular mechanisms remain poorly understood. Using SPR and NMR, here we report a direct, μM interaction between EGCG and the tumor suppressor p53 (KD = 1.6 ± 1.4 μM), with the disordered N-terminal domain (NTD) identified as the major binding site (KD = 4 ± 2 μM). Large scale atomistic simulations (>100 μs), SAXS and AUC demonstrate that EGCG-NTD interaction is dynamic and EGCG causes the emergence of a subpopulation of compact bound conformations. The EGCG-p53 interaction disrupts p53 interaction with its regulatory E3 ligase MDM2 and inhibits ubiquitination of p53 by MDM2 in an in vitro ubiquitination assay, likely stabilizing p53 for anti-tumor activity. Our work provides insights into the mechanisms for EGCG’s anticancer activity and identifies p53 NTD as a target for cancer drug discovery through dynamic interactions with small molecules.

scholarly journals Genetic Screens for Factors Involved in the Notum Bristle Loss of Interspecific Hybrids Between Drosophila melanogaster and D. simulans

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 269-282
Author(s):  
Toshiyuki Takano-Shimizu
Keyword(s):  
Drosophila Melanogaster ◽  
Interspecific Cross ◽  
Species Variation ◽  
Genetic Screens ◽  
Pure Species ◽  
Epistatic Interactions ◽  
X Chromosomes ◽  
Powerful Means ◽  
Different Populations ◽  
Deficiency Screening

Abstract Interspecific cross is a powerful means to uncover hidden within- and between-species variation in populations. One example is a bristle loss phenotype of hybrids between Drosophila melanogaster and D. simulans, although both the pure species have exactly the same pattern of bristle formation on the notum. There exists a large amount of genetic variability in the simulans populations with respect to the number of missing bristles in hybrids, and the variation is largely attributable to simulans X chromosomes. Using nine molecular markers, I screened the simulans X chromosome for genetic factors that were responsible for the differences between a pair of simulans lines with high (H) and low (L) missing bristle numbers. Together with duplication-rescue experiments, a single major quantitative locus was mapped to a 13F–14F region. Importantly, this region accounted for most of the differences between H and L lines in three other independent pairs, suggesting segregation of H and L alleles at the single locus in different populations. Moreover, a deficiency screening uncovered several regions with factors that potentially cause the hybrid bristle loss due to epistatic interactions with the other factors.

scholarly journals A closed-loop optogenetic screen for neurons controlling feeding in Drosophila

2021 ◽  
Author(s):  
Celia K S Lau ◽  
Meghan Jelen ◽  
Michael D Gordon
Keyword(s):  
Drosophila Melanogaster ◽  
Expression Pattern ◽  
Sensory Neurons ◽  
Closed Loop ◽  
Higher Order ◽  
Taste Detection ◽  
Proof Of Principle ◽  
Feeding Circuits

Abstract Feeding is an essential part of animal life that is greatly impacted by the sense of taste. Although the characterization of taste-detection at the periphery has been extensive, higher order taste and feeding circuits are still being elucidated. Here, we use an automated closed-loop optogenetic activation screen to detect novel taste and feeding neurons in Drosophila melanogaster. Out of 122 Janelia FlyLight Project GAL4 lines preselected based on expression pattern, we identify six lines that acutely promote feeding and 35 lines that inhibit it. As proof of principle, we follow up on R70C07-GAL4, which labels neurons that strongly inhibit feeding. Using split-GAL4 lines to isolate subsets of the R70C07-GAL4 population, we find both appetitive and aversive neurons. Furthermore, we show that R70C07-GAL4 labels putative second-order taste interneurons that contact both sweet and bitter sensory neurons. These results serve as a resource for further functional dissection of fly feeding circuits.

scholarly journals INTRACISTRONIC MAPPING OF ELECTROPHORETIC SITES IN DROSOPHILA MELANOGASTER: FIDELITY OF INFORMATION TRANSFER BY GENE CONVERSION

Genetics ◽  
1974 ◽  
Vol 76 (2) ◽  
pp. 289-299
Author(s):  
Margaret McCarron ◽  
William Gelbart ◽  
Arthur Chovnick
Keyword(s):  
Drosophila Melanogaster ◽  
Information Transfer ◽  
Large Scale ◽  
Genetic Basis ◽  
Xanthine Dehydrogenase ◽  
Specific Protein ◽  
Wild Type ◽  
Electrophoretic Variation ◽  
The Stability ◽  
Recombination Experiments

ABSTRACT A convenient method is described for the intracistronic mapping of genetic sites responsible for electrophoretic variation of a specific protein in Drosophila melanogaster. A number of wild-type isoalleles of the rosy locus have been isolated which are associated with the production of electrophoretically distinguishable xanthine dehydrogenases. Large-scale recombination experiments were carried out involving null enzyme mutants induced on electrophoretically distinct wild-type isoalleles, the genetic basis for which is followed as a nonselective marker in the cross. Additionally, a large-scale recombination experiment was carried out involving null enzyme rosy mutants induced on the same wild-type isoallele. Examination of the electrophoretic character of crossover and convertant products recovered from the latter experiment revealed that all exhibited the same parental electrophoretic character. In addition to documenting the stability of the xanthine dehydrogenase electrophoretic character, this observation argues against a special mutagenesis hypothesis to explain conversions resulting from allele recombination studies.

scholarly journals Integrative cBioPortal Analysis Revealed Molecular Mechanisms That Regulate EGFR-PI3K-AKT-mTOR Pathway in Diffuse Gliomas of the Brain

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3247
Author(s):  
Petar Brlek ◽  
Anja Kafka ◽  
Anja Bukovac ◽  
Nives Pećina-Šlaus
Keyword(s):  
Large Scale ◽  
Molecular Mechanisms ◽  
In Silico Analysis ◽  
Total Sample ◽  
Mtor Signaling ◽  
Biological Behavior ◽  
Mrna Transcription ◽  
Diffuse Gliomas ◽  
New Treatment ◽  
Using Data

Diffuse gliomas are a heterogeneous group of tumors with aggressive biological behavior and a lack of effective treatment methods. Despite new molecular findings, the differences between pathohistological types still require better understanding. In this in silico analysis, we investigated AKT1, AKT2, AKT3, CHUK, GSK3β, EGFR, PTEN, and PIK3AP1 as participants of EGFR-PI3K-AKT-mTOR signaling using data from the publicly available cBioPortal platform. Integrative large-scale analyses investigated changes in copy number aberrations (CNA), methylation, mRNA transcription and protein expression within 751 samples of diffuse astrocytomas, anaplastic astrocytomas and glioblastomas. The study showed a significant percentage of CNA in PTEN (76%), PIK3AP1 and CHUK (75% each), EGFR (74%), AKT2 (39%), AKT1 (32%), AKT3 (19%) and GSK3β (18%) in the total sample. Comprehensive statistical analyses show how genomics and epigenomics affect the expression of examined genes differently across various pathohistological types and grades, suggesting that genes AKT3, CHUK and PTEN behave like tumor suppressors, while AKT1, AKT2, EGFR, and PIK3AP1 show oncogenic behavior and are involved in enhanced activity of the EGFR-PI3K-AKT-mTOR signaling pathway. Our findings contribute to the knowledge of the molecular differences between pathohistological types and ultimately offer the possibility of new treatment targets and personalized therapies in patients with diffuse gliomas.

scholarly journals Polymodal Functionality of C. elegans OLL Neurons in Mechanosensation and Thermosensation

2021 ◽  
Author(s):  
Yuedan Fan ◽  
Wenjuan Zou ◽  
Jia Liu ◽  
Umar Al-Sheikh ◽  
Hankui Cheng ◽  
...  
Keyword(s):  
Glutamate Receptor ◽  
Sensory Neurons ◽  
Molecular Mechanisms ◽  
Temperature Sensitive ◽  
Cold Sensation ◽  
Cold Response ◽  
C Elegans ◽  
Sensory Modalities ◽  
A Cell ◽  
Bona Fide

AbstractSensory modalities are important for survival but the molecular mechanisms remain challenging due to the polymodal functionality of sensory neurons. Here, we report the C. elegans outer labial lateral (OLL) sensilla sensory neurons respond to touch and cold. Mechanosensation of OLL neurons resulted in cell-autonomous mechanically-evoked Ca2+ transients and rapidly-adapting mechanoreceptor currents with a very short latency. Mechanotransduction of OLL neurons might be carried by a novel Na+ conductance channel, which is insensitive to amiloride. The bona fide mechano-gated Na+-selective degenerin/epithelial Na+ channels, TRP-4, TMC, and Piezo proteins are not involved in this mechanosensation. Interestingly, OLL neurons also mediated cold but not warm responses in a cell-autonomous manner. We further showed that the cold response of OLL neurons is not mediated by the cold receptor TRPA-1 or the temperature-sensitive glutamate receptor GLR-3. Thus, we propose the polymodal functionality of OLL neurons in mechanosensation and cold sensation.

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