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

Abstract

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.

Review of octopamine in insect nervous systems

“…99 The ebony gene cloned from the P. americana brain shows homology with ebony sequences from Anopheles gambiae, A. mellifera, and D. melanogaster. 100 These studies support the occurrence of alanine conjugation as an alternative pathway for biogenic amine inactivation in the central nervous system of invertebrates, including insects. The γ-glutamylation is catalyzed by γ-glutamyltransferase.…”

“…The γ-glutamylation is catalyzed by γ-glutamyltransferase. 3,94,100 This pathway has been observed in the horseshoe crab Limulus brain and eyes where γ-glutamyl OCT plays a role as an intracellular transmitter in the Limulus visual system. 101 OCT inactivation via sulfation catalyzed by O-sulfotransferase has been reported in lobsters.…”

The metabolism of histamine in theDrosophilaoptic lobe involves an ommatidial pathway: β-alanine recycles through the retina

“…In the visual system, histamine -a neurotransmitter released by the synaptic terminals of fly photoreceptor neurons (Hardie, 1987;Sarthy, 1991) -is inactivated by conjugation to -alanine under the action of the -alanyl biogenic amine synthetase Ebony, which is expressed in neighbouring epithelial glial cells (Borycz et al, 2002). Ebony also acts in a similar fashion on other biogenic amines in the brain of the fruit fly Drosophila melanogaster (Richardt et al, 2003), confirming an early suggestion that -alanylation may be a general pathway for inactivating biogenic amines in insects (Evans, 1980;Blenau and Baumann, 2005).…”

Characterization of an Invertebrate-Type Dopamine Receptor of the American Cockroach, Periplaneta americana

“…Polymerase chain reaction (PCR) was performed on a P. americana- brain cDNA library [104] under the following conditions: 1 cycle of 2.5 min at 94 °C, followed by 35 cycles of 40 s at 94 °C, 40 s at 45 °C, and 30 s at 72 °C, and a final extension of 10 min at 72 °C. The PCR products were cloned into pGEM-T vector (Promega, Mannheim, Germany) and subsequently analyzed by DNA sequencing (AGOWA, Berlin, Germany).…”