Similar Datasets
Project description:Modifications of mRNA, especially methylation of adenosine, have recently drawn much attention. The much rarer modification, 5-hydroxymethylation of cytosine (5hmC), is not well understood and is the subject of this study. Vertebrate Tet proteins are 5-methylcytosine (5mC) hydroxylases enzymes catalyzing the transition of 5mC to 5hmC in DNA and have recently been shown to have the same function in messenger RNAs in both vertebrates and in Drosophila. The Tet gene is essential in Drosophila because Tet knock-out animals do not reach adulthood. We describe the identification of Tet-target genes in the embryo and larval brain by determining Tet DNA-binding sites throughout the genome and by mapping the Tet-dependent 5hmrC modifications transcriptome-wide. 5hmrC-modified sites can be found along the entire transcript and are preferentially located at the promoter where they overlap with histone H3K4me3 peaks. The identified mRNAs are frequently involved in neuron and axon development and Tet knock-out led to a reduction of 5hmrC marks on specific mRNAs. Among the Tet-target genes were the robo2 receptor and its slit ligand that function in axon guidance in Drosophila and in vertebrates. Tet knock-out embryos show overlapping phenotypes with robo2 and are sensitized to reduced levels of slit. Both Robo2 and Slit protein levels were markedly reduced in Tet KO larval brains. Our results establish a role for Tet-dependent 5hmrC in facilitating the translation of modified mRNAs, primarily in developing nerve cells.
2024-02-23 | GSE225979 | GEO
Project description:Modifications of mRNA, especially methylation of adenosine, have recently drawn much attention. The much rarer modification, 5-hydroxymethylation of cytosine (5hmC), is not well understood and is the subject of this study. Vertebrate Tet proteins are 5-methylcytosine (5mC) hydroxylases enzymes catalyzing the transition of 5mC to 5hmC in DNA and have recently been shown to have the same function in messenger RNAs in both vertebrates and in Drosophila. The Tet gene is essential in Drosophila because Tet knock-out animals do not reach adulthood. We describe the identification of Tet-target genes in the embryo and larval brain by determining Tet DNA-binding sites throughout the genome and by mapping the Tet-dependent 5hmrC modifications transcriptome-wide. 5hmrC-modified sites can be found along the entire transcript and are preferentially located at the promoter where they overlap with histone H3K4me3 peaks. The identified mRNAs are frequently involved in neuron and axon development and Tet knock-out led to a reduction of 5hmrC marks on specific mRNAs. Among the Tet-target genes were the robo2 receptor and its slit ligand that function in axon guidance in Drosophila and in vertebrates. Tet knock-out embryos show overlapping phenotypes with robo2 and are sensitized to reduced levels of slit. Both Robo2 and Slit protein levels were markedly reduced in Tet KO larval brains. Our results establish a role for Tet-dependent 5hmrC in facilitating the translation of modified mRNAs, primarily in developing nerve cells.
2024-02-23 | GSE225969 | GEO
Project description:Modifications of mRNA, especially methylation of adenosine, have recently drawn much attention. The much rarer modification, 5-hydroxymethylation of cytosine (5hmC), is not well understood and is the subject of this study. Vertebrate Tet proteins are 5-methylcytosine (5mC) hydroxylases enzymes catalyzing the transition of 5mC to 5hmC in DNA and have recently been shown to have the same function in messenger RNAs in both vertebrates and in Drosophila. The Tet gene is essential in Drosophila because Tet knock-out animals do not reach adulthood. We describe the identification of Tet-target genes in the embryo and larval brain by determining Tet DNA-binding sites throughout the genome and by mapping the Tet-dependent 5hmrC modifications transcriptome-wide. 5hmrC-modified sites can be found along the entire transcript and are preferentially located at the promoter where they overlap with histone H3K4me3 peaks. The identified mRNAs are frequently involved in neuron and axon development and Tet knock-out led to a reduction of 5hmrC marks on specific mRNAs. Among the Tet-target genes were the robo2 receptor and its slit ligand that function in axon guidance in Drosophila and in vertebrates. Tet knock-out embryos show overlapping phenotypes with robo2 and are sensitized to reduced levels of slit. Both Robo2 and Slit protein levels were markedly reduced in Tet KO larval brains. Our results establish a role for Tet-dependent 5hmrC in facilitating the translation of modified mRNAs, primarily in developing nerve cells.
2024-02-23 | GSE225970 | GEO
Project description:Precise wiring of the nervous system depends on coordinating the action of conserved families of proteins that direct axons to their appropriate targets. Slit-roundabout repulsion and netrin-deleted in colorectal cancer (DCC) (frazzled) attraction must be tightly regulated to control midline axon guidance in vertebrates and invertebrates, but the mechanism mediating this regulation is poorly defined. Here, we show that the Fra receptor has two genetically separable functions in regulating midline guidance in Drosophila. First, Fra mediates canonical chemoattraction in response to netrin, and, second, it functions independently of netrin to activate commissureless transcription, allowing attraction to be coupled to the down-regulation of repulsion in precrossing commissural axons.
| S-EPMC4078765 | biostudies-literature
Project description:During the development of the Drosophila central nervous system the process of midline crossing is orchestrated by a number of guidance receptors and ligands. Many key axon guidance molecules have been identified in both invertebrates and vertebrates, but the transcriptional regulation of growth cone guidance remains largely unknown. One open question is whether transcriptional regulation plays a role in midline crossing, or if local translation can account for the necessary fine tuning of protein levels. To investigate this issue, we conducted a genome wide analysis of transcription in Drosophila embryos using wild type and a number of well-characterized Drosophila guidance mutants and transgenics. We also analyzed a publicly available microarray time course of Drosophila embryonic development with an axon guidance focus. Using hopach, a novel clustering method which is well suited to microarray data analysis, we identified groups of genes with similar expression patterns across guidance mutants and transgenics. We then systematically characterized the resulting clusters with respect to their relevance to axon guidance using two complementary controlled vocabularies: the Gene Ontology (GO) and anatomical annotations of the Atlas of Pattern of Gene Expression (APoGE) in situ hybridization database. The analysis indicates that regulation of gene expression does play a role in the process of axon guidance in Drosophila. We also find a strong link between axon guidance and hemocyte migration, a result that agrees with mounting evidence that axon guidance molecules are co-opted in vertebrate vascularization. Cell cyclin activity in the context of axon guidance is also suggested from our array data. RNA and protein patterns of cell cyclin in axon guidance mutants and transgenics support this possible link. This study provides important insights into the regulation of axon guidance in vivo and suggests that transcription does play a role in control of axon guidance. Keywords: Mutant Analysis
2006-12-14 | GSE6515 | GEO
Project description:During gastrulation in Drosophila, ventral cells change shape, undergoing synchronous apical constriction, to create the ventral furrow (VF). This process is affected in mutant embryos lacking zygotic function of the folded gastrulation (fog) gene, which encodes a putative secreted protein. Fog is an essential autocrine signal that induces cytoskeletal changes in invaginating VF cells. Here we show that Fog is also required for nervous system development. Fog is expressed by longitudinal glia in the central nervous system (CNS), and reducing its expression in glia causes defects in process extension and axon ensheathment. Glial Fog overexpression produces a disorganized glial lattice. Fog has a distinct set of functions in CNS neurons. Our data show that reduction or overexpression of Fog in these neurons produces axon guidance phenotypes. Interestingly, these phenotypes closely resemble those seen in embryos with altered expression of the receptor tyrosine phosphatase PTP52F. We conducted epistasis experiments to define the genetic relationships between Fog and PTP52F, and the results suggest that PTP52F is a downstream component of the Fog signaling pathway in CNS neurons. We also found that Ptp52F mutants have early VF phenotypes like those seen in fog mutants.
| S-EPMC2041958 | biostudies-literature
Project description:Ten-eleven translocation (Tet) is an important gene in neurodevelopment, but how Tet regulates brain development is still under study. Mutations in human TET proteins have been found in individuals with neurodevelopmental disorders. Here we report a new function of Tet in regulating Drosophila early brain development. We found that mutation on the Tet DNA-binding domain (TetAXXC) resulted in axon guidance defects in the mushroom body (MB). Tet is required in early brain development during the outgrowth of MB β axons. Transcriptomic study of TetAXXC mutant and wild-type pupal brains shows that glutamine synthetase 2 (Gs2), a key enzyme in glutamatergic signaling, is the most significantly down-regulated gene in the Tet mutant brains. RNAi knockdown or CRISPR/Cas9 mutagenesis of Gs2 recapitulates the TetAXXC phenotype. Surprisingly, Tet and Gs2 act in the insulin-producing cells (IPCs) to control MB axon guidance, and overexpression of Gs2 in the IPCs rescue the axonal defects of TetAXXC. Treating TetAXXC with the metabotropic glutamate receptor antagonist MPEP can also rescue the phenotype confirming Tet function in regulating glutamatergic signaling. TetAXXC and the Drosophila homolog of Fragile X Messenger Ribonucleoprotein protein mutant (Fmr13) have similar mushroom body axonal defects and reduction in Gs2 transcription, and, importantly, overexpression of Gs2 in the IPCs of Fmr1 mutants also rescues the axonal defects. Our studies reveal a new function of Tet in regulating axon guidance in the brain via glutamatergic signaling and suggest overlapping functions between Tet and Fmr1.
2024-04-20 | GSE231534 | GEO
Project description:Signaling through the Notch receptor has dramatically different effects depending on cell type and developmental timing. While a myriad of biological systems affected by Notch have been described, the molecular mechanisms by which a generic Notch signal is translated into a cell-type-specific output are less clear. Canonically, the Notch intracellular domain (NICD) translocates into the nucleus upon ligand binding to transcriptionally regulate target genes. In order to generate specificity, therefore, additional factors must exist that modulate NICD activity. Here we describe a novel regulator of the Notch pathway, Endonuclease GI (EndoGI). EndoGI localizes to the nucleus of most cells and activates Notch signaling when overexpressed. In the absence of endoGI, mutant animals are viable, but uncoordinated as motor neurons fail to innervate their appropriate muscle targets. Our data is therefore consistent with EndoGI functioning as a positive regulator of the Notch signaling pathway, playing a critical role during axon guidance of motor neurons.
| S-EPMC3039039 | biostudies-literature
Project description:Tuberous sclerosis complex is a disease caused by mutations in the TSC1 or TSC2 genes, which encode a protein complex that inhibits mTOR kinase signaling by inactivating the Rheb GTPase. Activation of mTOR promotes the formation of benign tumors in various organs and the mechanisms underlying the neurological symptoms of the disease remain largely unknown. We found that Tsc2 haploinsufficiency in mice caused aberrant retinogeniculate projections that suggest defects in EphA receptor-dependent axon guidance. We also found that EphA receptor activation by ephrin-A ligands in neurons led to inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) activity and decreased inhibition of Tsc2 by ERK1/2. Thus, ephrin stimulation inactivates the mTOR pathway by enhancing Tsc2 activity. Furthermore, Tsc2 deficiency and hyperactive Rheb constitutively activated mTOR and inhibited ephrin-induced growth cone collapse. Our results indicate that TSC2-Rheb-mTOR signaling cooperates with the ephrin-Eph receptor system to control axon guidance in the visual system.
| S-EPMC2812631 | biostudies-literature
Project description:During development, precise temporal and spatial gradients are responsible for guiding axons to their appropriate targets. Within the developing ventral midbrain (VM) the cues that guide dopaminergic (DA) axons to their forebrain targets remain to be fully elucidated. Wnts are morphogens that have been identified as axon guidance molecules. Several Wnts are expressed in the VM where they regulate the birth of DA neurons. Here, we describe that a precise temporo-spatial expression of Wnt5a accompanies the development of nigrostriatal projections by VM DA neurons. In mice at E11.5, Wnt5a is expressed in the VM where it was found to promote DA neurite and axonal growth in VM primary cultures. By E14.5, when DA axons are approaching their striatal target, Wnt5a causes DA neurite retraction in primary cultures. Co-culture of VM explants with Wnt5a-overexpressing cell aggregates revealed that Wnt5a is capable of repelling DA neurites. Antagonism experiments revealed that the effects of Wnt5a are mediated by the Frizzled receptors and by the small GTPase, Rac1 (a component of the non-canonical Wnt planar cell polarity pathway). Moreover, the effects were specific as they could be blocked by Wnt5a antibody, sFRPs and RYK-Fc. The importance of Wnt5a in DA axon morphogenesis was further verified in Wnt5a-/- mice, where fasciculation of the medial forebrain bundle (MFB) as well as the density of DA neurites in the MFB and striatal terminals were disrupted. Thus, our results identify a novel role of Wnt5a in DA axon growth and guidance.
| S-EPMC3069098 | biostudies-literature