Ebony protein in the <i>Drosophila</i> nervous system: Optic neuropile expression in glial cells

Richardt, Arnd; Rybak, Jürgen; Störtkuhl, Klemens F.; Meinertzhagen, Ian A.; Hovemann, Bernhard T.

doi:10.1002/cne.10360

Cited by 80 publications

(126 citation statements)

References 48 publications

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“…Histamine, which has been identified as neurotransmitter at these terminals, is released when retinula cells are depolarized (10). Because Ebony is expressed in the lamina glia surrounding the photoreceptor terminals that lack dopamine immunoreactivity, we previously proposed that glial expression reflects histamine conjugation to ␤-alanine (11). Recent evidence from the elucidation of histamine metabolism in fly heads (12) supported our above-mentioned hypothesis.…”

supporting

confidence: 59%

“…Putative Ebony Function in Neurotransmitter MetabolismEbony is expressed in diverse tissues at different times during development (11). Nervous system activity has been predicted from the behavioral and visual phenotype of the mutant but was only recently confirmed by activity staining of an ebonylacZ fusion gene transformant and by immunocytochemistry (11,13).…”

Section: Discussionmentioning

confidence: 99%

“…Nervous system activity has been predicted from the behavioral and visual phenotype of the mutant but was only recently confirmed by activity staining of an ebonylacZ fusion gene transformant and by immunocytochemistry (11,13). The puzzling fact that evidence for dopaminergic neurons in the lamina was lacking (30) led to experiments that revealed that Ebony is involved in ␤-alanyl-histamine formation in the eye (12).…”

Section: Discussionmentioning

confidence: 99%

“…Before evaluating the functionality of the expressed Ebony proteins, we had to confirm that each of the transformed cDNA copies was faithfully translated. Immunochemical detection of Ebony was performed with an antiserum raised against the C-terminal portion of the protein (11). As shown in Fig.…”

Section: Figmentioning

confidence: 99%

“…Recent evidence from the elucidation of histamine metabolism in fly heads (12) supported our above-mentioned hypothesis. Throughout fly development, the optic neuropile is not the sole but the major site of ebony expression in the nervous system (11,13). This finding raised the intriguing possibility that ␤-alanylation reflects an as yet unknown general pathway for biogenic amine neurotransmitter inactivation.…”

mentioning

confidence: 99%

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Ebony, a Novel Nonribosomal Peptide Synthetase for β-Alanine Conjugation with Biogenic Amines in Drosophila

Richardt¹,

Kemme²,

Wagner³

et al. 2003

Journal of Biological Chemistry

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Using Ebony protein either expressed in Escherichia coli or in Schneider S2 cells, we provide evidence for its substrate specificity and reaction mechanism. Ebony activates ␤-alanine to aminoacyladenylate by an adenylation domain and covalently attaches it as a thioester to a thiolation domain in a nonribosomal peptide synthetase (NRPS) related mechanism. In a second reaction, biogenic amines act as external nucleophiles on ␤-alanyl-S-pantetheine-Ebony, thereby releasing in a fast reaction the dipeptide (peptidoamine) in a process that is novel in higher eucaryotes. Therefore, we define Ebony as a ␤-alanyl-biogenic amine synthetase. Insight into the reaction mechanism stems from mutational analysis of an invariant serine that disclosed Ebony as a multienzyme with functional analogy to the starting modules of NRPSs. In light of a putative biogenic amine-deactivating capacity, Ebony function in the nervous system must be reconsidered. We propose that in the Drosophila eye Ebony is involved in the transmission process by inactivation of histamine through ␤-alanyl conjugation.

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supporting

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

mentioning

confidence: 99%

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Ebony, a Novel Nonribosomal Peptide Synthetase for β-Alanine Conjugation with Biogenic Amines in Drosophila

Richardt¹,

Kemme²,

Wagner³

et al. 2003

Journal of Biological Chemistry

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129

138

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Molecular characterization of the ebony gene from the American cockroach, Periplaneta americana

Blenau¹,

Baumann²

2005

Arch Insect Biochem Physiol

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Biogenic amines are an important class of primary messengers in the central (CNS) and peripheral nervous systems and in peripheral organs. These substances regulate and modulate many physiological and behavioral processes. Various inactivation mechanisms for these substances exist to terminate biogenic amine-mediated signal transduction. In vertebrates, the enzymes monoamine oxidase and/or catechol-O-methyl-transferase are involved in these processes. In insects, however, in which both enzymes are low in abundance or absent, biogenic amines are inactivated mainly by N-acetylation or O-sulphation. In Drosophila, beta-alanyl conjugation mediated by the Ebony protein has recently been shown to be a novel and alternative pathway for biogenic amine inactivation. Here, we report the cloning of ebony cDNA (Peaebony) from a brain-specific cDNA library of the cockroach Periplaneta americana. The open reading frame encodes a protein of 860 amino acid residues (PeaEbony). The PeaEbony polypeptide shares homology to Ebony sequences from Anopheles gambiae, Apis mellifera, and Drosophila melanogaster. In addition, PeaEbony exhibits sequence similarity to a family of microbial non-ribosomal peptide synthetases. The mRNA encoding PeaEbony is highly expressed in the cockroach brain and to a lesser extent in the salivary glands. PeaEbony is, therefore, probably involved in the inactivation of various biogenic amines through beta-alanyl conjugation in the cockroach CNS. Since the salivary glands in Periplaneta are innervated by dopaminergic and serotonergic neurons, PeaEbony probably also biochemically modifies dopamine and serotonin in these acinar glands.

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Drosophila photoreceptors express cysteine peptidase tan

Wagner¹,

Heseding²,

Szlachta³

et al. 2006

J of Comparative Neurology

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The Drosophila mutant tan (t) shows reciprocal pigmentation defects compared with the ebony (e) mutant. Visual phenotypes, however, are similar in both flies: Electroretinogram (ERG) recordings lack "on" and "off" transients, an indication of impaired synaptic transmission to postsynaptic cells L1 and L2. Cloning of tan revealed transcription of the gene in the retina, apparently in photoreceptor cells. We expressed Tan in Escherichia coli and confirmed by Western blotting and mass spectroscopic analyses that Tan is expressed as preprotein, followed by proteolytic cleavage into two subunits at a conserved --Gly--Cys-- motif like its fungal ortholog isopenicillin-N N-acyltransferase (IAT). Tan thus belongs to the large family of cysteine peptidases. To discriminate expression of Tan and Ebony in retina and optic neuropils, we raised antisera against specific Tan peptides. Testing for colocalization with GMR-driven n-Syb-GFP labeling revealed that Tan expression is confined to the photoreceptor cells R1-R8. A close proximity of Tan and Ebony expression is evident in lamina cartridges, where three epithelial glia cells envelop the six photoreceptor terminals R1-R6. In the medulla, R7/R8 axonal terminals appeared lined up side by side with glial extensions. This local proximity supports a model for Drosophila visual synaptic transmission in which Tan and Ebony interact biochemically in a putative histamine inactivation and recycling pathway in Drosophila.

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Ebony protein in the Drosophila nervous system: Optic neuropile expression in glial cells

Cited by 80 publications

References 48 publications

Ebony, a Novel Nonribosomal Peptide Synthetase for β-Alanine Conjugation with Biogenic Amines in Drosophila

Ebony, a Novel Nonribosomal Peptide Synthetase for β-Alanine Conjugation with Biogenic Amines in Drosophila

Molecular characterization of the ebony gene from the American cockroach, Periplaneta americana

Drosophila photoreceptors express cysteine peptidase tan

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