Transmembrane channel-like (tmc) gene regulates Drosophila larval locomotion

Drosophila larval locomotion, which entails rhythmic body contractions, is controlled by sensory feedback from proprioceptors. The molecular mechanisms mediating this feedback are little understood. By using genetic knock-in and immunostaining, we found that the Drosophila melanogaster transmembrane channel-like (tmc) gene is expressed in the larval class I and class II dendritic arborization (da) neurons and bipolar dendrite (bd) neurons, both of which are known to provide sensory feedback for larval locomotion. Larvae with knockdown or loss of tmc function displayed reduced crawling speeds, increased head cast frequencies, and enhanced backward locomotion. Expressing Drosophila TMC or mammalian TMC1 and/or TMC2 in the tmc-positive neurons rescued these mutant phenotypes. Bending of the larval body activated the tmc-positive neurons, and in tmc mutants this bending response was impaired. This implicates TMC’s roles in Drosophila proprioception and the sensory control of larval locomotion. It also provides evidence for a functional conservation between Drosophila and mammalian TMCs.

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Targeted Expression of the Class II Phosphoinositide 3-Kinase in Drosophila melanogaster Reveals Lipid Kinase-Dependent Effects on Patterning and Interactions with Receptor Signaling Pathways

Molecular and Cellular Biology ◽

10.1128/mcb.24.2.796-808.2004 ◽

2004 ◽

Vol 24 (2) ◽

pp. 796-808 ◽

Cited By ~ 22

Author(s):

Lindsay K. MacDougall ◽

Mary Elizabeth Gagou ◽

Sally J. Leevers ◽

Ernst Hafen ◽

Michael D. Waterfield

Keyword(s):

Drosophila Melanogaster ◽

Signaling Pathways ◽

Egf Receptor ◽

Adaptor Protein ◽

Class Ii ◽

Notch Receptor ◽

Mitogen Activated Protein Kinase ◽

Class I ◽

Wing Venation ◽

Receptor Signaling

ABSTRACT Phosphoinositide 3-kinases (PI3Ks) can be divided into three distinct classes (I, II, and III) on the basis of their domain structures and the lipid signals that they generate. Functions have been assigned to the class I and class III enzymes but have not been established for the class II PI3Ks. We have obtained the first evidence for a biological function for a class II PI3K by expressing this enzyme during Drosophila melanogaster development and by using deficiencies that remove the endogenous gene. Wild-type and catalytically inactive PI3K_68D transgenes have opposite effects on the number of sensory bristles and on wing venation phenotypes induced by modified epidermal growth factor (EGF) receptor signaling. These results indicate that the endogenous PI3K_68D may act antagonistically to the EGF receptor-stimulated Ras-mitogen-activated protein kinase pathway and downstream of, or parallel to, the Notch receptor. A class II polyproline motif in PI3K_68D can bind the Drk adaptor protein in vitro, primarily via the N-terminal SH3 domain of Drk. Drk may thus be important for the localization of PI3K_68D, allowing it to modify signaling pathways downstream of cell surface receptors. The phenotypes obtained are markedly distinct from those generated by expression of the Drosophila class I PI3K, which affects growth but not pattern formation.

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Gαq and Phospholipase Cβ signaling regulate nociceptor sensitivity in Drosophila melanogaster larvae

PeerJ ◽

10.7717/peerj.5632 ◽

2018 ◽

Vol 6 ◽

pp. e5632 ◽

Cited By ~ 2

Author(s):

Joshua A. Herman ◽

Adam B. Willits ◽

Andrew Bellemer

Keyword(s):

Drosophila Melanogaster ◽

Body Wall ◽

Molecular Mechanisms ◽

Genetic Manipulation ◽

Sensory Function ◽

Mechanical Stimuli ◽

Larval Body ◽

Future Studies ◽

Signaling Mechanisms ◽

Polymodal Nociceptor

Drosophila melanogaster larvae detect noxious thermal and mechanical stimuli in their environment using polymodal nociceptor neurons whose dendrites tile the larval body wall. Activation of these nociceptors by potentially tissue-damaging stimuli elicits a stereotyped escape locomotion response. The cellular and molecular mechanisms that regulate nociceptor function are increasingly well understood, but gaps remain in our knowledge of the broad mechanisms that control nociceptor sensitivity. In this study, we use cell-specific knockdown and overexpression to show that nociceptor sensitivity to noxious thermal and mechanical stimuli is correlated with levels of Gαq and phospholipase Cβ signaling. Genetic manipulation of these signaling mechanisms does not result in changes in nociceptor morphology, suggesting that changes in nociceptor function do not arise from changes in nociceptor development, but instead from changes in nociceptor activity. These results demonstrate roles for Gαq and phospholipase Cβ signaling in facilitating the basal sensitivity of the larval nociceptors to noxious thermal and mechanical stimuli and suggest future studies to investigate how these signaling mechanisms may participate in neuromodulation of sensory function.

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Transcriptome and DNA Methylation Analyses of the Molecular Mechanisms Underlying with Longissimus dorsi Muscles at Different Stages of Development in the Polled Yak

Genes ◽

10.3390/genes10120970 ◽

2019 ◽

Vol 10 (12) ◽

pp. 970 ◽

Cited By ~ 1

Author(s):

Ma ◽

Jia ◽

Chu ◽

Fu ◽

Lei ◽

...

Keyword(s):

Dna Methylation ◽

Molecular Mechanisms ◽

Expression Patterns ◽

Methylation Status ◽

Muscle Growth ◽

Class Ii ◽

Epigenetic Mechanism ◽

Class I ◽

Longissimus Dorsi ◽

Growth Stages

DNA methylation modifications are implicated in many biological processes. As the most common epigenetic mechanism DNA methylation also affects muscle growth and development. The majority of previous studies have focused on different varieties of yak, but little is known about the epigenetic regulation mechanisms in different age groups of animals. The development of muscles in the different stages of yak growth remains unclear. In this study, we selected the longissimus dorsi muscle tissue at three different growth stages of the yak, namely, 90-day-old fetuses (group E), six months old (group M), and three years old (group A). Using RNA-Seq transcriptome sequencing and methyl-RAD whole-genome methylation sequencing technology, changes in gene expression levels and DNA methylation status throughout the genome were investigated during the stages of yak development. Each group was represented by three biological replicates. The intersections of expression patterns of 7694 differentially expressed genes (DEGs) were identified (padj < 0.01, |log2FC| > 1.2) at each of the three developmental periods. Time-series expression profile clustering analysis indicated that the DEGs were significantly arranged into eight clusters which could be divided into two classes (padj < 0.05), class I profiles that were downregulated and class II profiles that were upregulated. Based on this cluster analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that DEGs from class I profiles were significantly (padj < 0.05) enriched in 21 pathways, the most enriched pathway being the Axon guidance signaling pathway. DEGs from the class II profile were significantly enriched in 58 pathways, the pathway most strongly enriched being Metabolic pathway. After establishing the methylation profiles of the whole genomes, and using two groups of comparisons, the three combinations of groups (M-vs.-E, M-vs.-A, A-vs.-E) were found to have 1344, 822, and 420 genes, respectively, that were differentially methylated at CCGG sites and 2282, 3056, and 537 genes, respectively, at CCWGG sites. The two sets of data were integrated and the negative correlations between DEGs and differentially methylated promoters (DMPs) analyzed, which confirmed that TMEM8C, IGF2, CACNA1S and MUSTN1 were methylated in the promoter region and that expression of the modified genes was negatively correlated. Interestingly, these four genes, from what was mentioned above, perform vital roles in yak muscle growth and represent a reference for future genomic and epigenomic studies in muscle development, in addition to enabling marker-assisted selection of growth traits.

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Gain of cis-regulatory activities underlies novel domains of wingless gene expression in Drosophila

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1509022112 ◽

2015 ◽

Vol 112 (24) ◽

pp. 7524-7529 ◽

Cited By ~ 58

Author(s):

Shigeyuki Koshikawa ◽

Matt W. Giorgianni ◽

Kathy Vaccaro ◽

Victoria A. Kassner ◽

John H. Yoder ◽

...

Keyword(s):

Gene Expression ◽

Drosophila Melanogaster ◽

Molecular Mechanisms ◽

Morphological Diversity ◽

Regulatory Sequences ◽

Animal Development ◽

Functional Conservation ◽

Common Path ◽

Molecular Events ◽

New Gene

Changes in gene expression during animal development are largely responsible for the evolution of morphological diversity. However, the genetic and molecular mechanisms responsible for the origins of new gene-expression domains have been difficult to elucidate. Here, we sought to identify molecular events underlying the origins of three novel features of wingless (wg) gene expression that are associated with distinct pigmentation patterns in Drosophila guttifera. We compared the activity of cis-regulatory sequences (enhancers) across the wg locus in D. guttifera and Drosophila melanogaster and found strong functional conservation among the enhancers that control similar patterns of wg expression in larval imaginal discs that are essential for appendage development. For pupal tissues, however, we found three novel wg enhancer activities in D. guttifera associated with novel domains of wg expression, including two enhancers located surprisingly far away in an intron of the distant Wnt10 gene. Detailed analysis of one enhancer (the vein-tip enhancer) revealed that it overlapped with a region controlling wg expression in wing crossveins (crossvein enhancer) in D. guttifera and other species. Our results indicate that one novel domain of wg expression in D. guttifera wings evolved by co-opting pre-existing regulatory sequences governing gene activity in the developing wing. We suggest that the modification of existing enhancers is a common path to the evolution of new gene-expression domains and enhancers.

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Phosphoinositide 3-Kinase C2β Regulates Cytoskeletal Organization and Cell Migration via Rac-dependent Mechanisms

Molecular Biology of the Cell ◽

10.1091/mbc.e05-11-1083 ◽

2006 ◽

Vol 17 (9) ◽

pp. 3729-3744 ◽

Cited By ~ 54

Author(s):

Roy M. Katso ◽

Olivier E. Pardo ◽

Andrea Palamidessi ◽

Clemens M. Franz ◽

Marin Marinov ◽

...

Keyword(s):

Cell Migration ◽

Molecular Mechanisms ◽

Egf Receptor ◽

Human Tumor ◽

Class Ii ◽

Dominant Negative ◽

Class I ◽

Membrane Ruffling ◽

And Migration ◽

Phosphoinositide 3 Kinase

Receptor-linked class I phosphoinositide 3-kinases (PI3Ks) induce assembly of signal transduction complexes through protein–protein and protein–lipid interactions that mediate cell proliferation, survival, and migration. Although class II PI3Ks have the potential to make the same phosphoinositides as class I PI3Ks, their precise cellular role is currently unclear. In this report, we demonstrate that class II phosphoinositide 3-kinase C2β (PI3KC2β) associates with the Eps8/Abi1/Sos1 complex and is recruited to the EGF receptor as part of a multiprotein signaling complex also involving Shc and Grb2. Increased expression of PI3KC2β stimulated Rac activity in A-431 epidermoid carcinoma cells, resulting in enhanced membrane ruffling and migration speed of the cells. Conversely, expression of dominant negative PI3KC2β reduced Rac activity, membrane ruffling, and cell migration. Moreover, PI3KC2β-overexpressing cells were protected from anoikis and displayed enhanced proliferation, independently of Rac function. Taken together, these findings suggest that PI3KC2β regulates the migration and survival of human tumor cells by distinct molecular mechanisms.

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A class I odorant receptor enhancer shares a functional motif with class II enhancers

Scientific Reports ◽

10.1038/s41598-020-79980-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tetsuo Iwata ◽

Satoshi Tomeoka ◽

Junji Hirota

Keyword(s):

Molecular Mechanisms ◽

Odorant Receptor ◽

Regulatory Element ◽

Mammalian Species ◽

Class Ii ◽

Class I ◽

Enhancer Activity ◽

Functional Motif ◽

Functional Region ◽

Or Genes

AbstractIn the mouse, 129 functional class I odorant receptor (OR) genes reside in a ~ 3 megabase huge gene cluster on chromosome 7. The J element, a long-range cis-regulatory element governs the singular expression of class I OR genes by exerting its effect over the whole cluster. To elucidate the molecular mechanisms underlying class I-specific enhancer activity of the J element, we analyzed the J element sequence to determine the functional region and essential motif. The 430-bp core J element, that is highly conserved in mammalian species from the platypus to humans, contains a class I-specific conserved motif of AAACTTTTC, multiple homeodomain sites, and a neighboring O/E-like site, as in class II OR-enhancers. A series of transgenic reporter assays demonstrated that the class I-specific motif is not essential, but the 330-bp core J-H/O containing the homeodomain and O/E-like sites is necessary and sufficient for class I-specific enhancer activity. Further motif analysis revealed that one of homeodomain sequence is the Greek Islands composite motif of the adjacent homeodomain and O/E-like sequences, and mutations in the composite motif abolished or severely reduced class I-enhancer activity. Our results demonstrate that class I and class II enhancers share a functional motif for their enhancer activity.

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Comparative Analysis of Position–Effect Variegation Mutations in Drosophila melanogaster Delineates the Targets of Modifiers

Genetics ◽

10.1093/genetics/148.2.733 ◽

1998 ◽

Vol 148 (2) ◽

pp. 733-741

Author(s):

Georgette L Sass ◽

Steven Henikoff

Keyword(s):

Drosophila Melanogaster ◽

Chromosomal Rearrangements ◽

Position Effect ◽

Reporter Genes ◽

Class Ii ◽

Class I ◽

Position Effect Variegation ◽

Heterochromatin Formation ◽

Transposon Insertion ◽

Effect Variegation

Abstract In Drosophila melanogaster, heterochromatin-induced silencing or position–effect variegation (PEV) of a reporter gene has provided insights into the properties of heterochromatin. Class I modifiers suppress PEV, and class II modifiers enhance PEV when the modifier gene is present in fewer than two doses. We have examined the effects of both class I and class II modifiers on four PEV mutations. These mutations include the inversions In(1)wm4 and In(2R)bwVDe2, which are classical chromosomal rearrangements that typify PEV mutations. The other mutations are a derivative of brownDominant, in which brown+ reporters are inactivated by a large block of heterochromatin, and a P[white+] transposon insertion associated with second chromosome heterochromatin. In general, we find that class I modifiers affect both classical and nonclassical PEV mutations, whereas class II modifiers affect only classical PEV mutations. We suggest that class II modifiers affect chromatin architecture in the vicinity of reporter genes, and only class I modifiers identify proteins that are potentially involved in heterochromatin formation or maintenance. In addition, our observations support a model in which there are different constraints on the process of heterochromatin-induced silencing in classical vs. nonclassical PEV mutations.

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Electron microscopy analysis of degenerating pancreatic ß cells in transgenic mice expressing the MHC Class I antigen Dd

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160297 ◽

1990 ◽

Vol 48 (3) ◽

pp. 548-549

Author(s):

T. A. Stewart ◽

D. Liggitt ◽

S. Pitts ◽

L. Martin ◽

M. Siegel ◽

...

Keyword(s):

Type I Diabetes ◽

Disease Process ◽

Class Ii ◽

Class I ◽

Type I ◽

Aberrant Expression ◽

Mhc Molecules ◽

Endogenous Insulin ◽

Class Ii Mhc ◽

Ifn Γ

Insulin-dependant (Type I) diabetes mellitus (IDDM) is a metabolic disorder resulting from the lack of endogenous insulin secretion. The disease is thought to result from the autoimmune mediated destruction of the insulin producing ß cells within the islets of Langerhans. The disease process is probably triggered by environmental agents, e.g. virus or chemical toxins on a background of genetic susceptibility associated with particular alleles within the major histocompatiblity complex (MHC). The relation between IDDM and the MHC locus has been reinforced by the demonstration of both class I and class II MHC proteins on the surface of ß cells from newly diagnosed patients as well as mounting evidence that IDDM has an autoimmune pathogenesis. In 1984, a series of observations were used to advance a hypothesis, in which it was suggested that aberrant expression of class II MHC molecules, perhaps induced by gamma-interferon (IFN γ) could present self antigens and initiate an autoimmune disease. We have tested some aspects of this model and demonstrated that expression of IFN γ by pancreatic ß cells can initiate an inflammatory destruction of both the islets and pancreas and does lead to IDDM.

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