Constitutive expression and enzymatic activity of Tan protein in brain and epidermis of Ceratitis capitata and of Drosophila melanogaster wild-type and tan mutants

The present report shows a partial biochemical characterization and life cycle expression of N-β-alanyldopamine hydrolase (Tan protein) in Ceratitis capitata and Drosophila melanogaster. This enzyme catalyzes the hydrolysis of N-β-alanyldopamine (NBAD), the main tanning precursor of insect brown cuticles. It also plays an important role in the metabolism of brain neurotransmitters, recycling dopamine and histamine. In contrast to NBAD-synthase, Tan is expressed constitutively in epidermis and does not respond directly to microbial challenge. Immunodetection experiments showed the novel localization of NBAD-hydrolase in the embryo central neural system and in different regions of the adult brain, in addition to optic lobes. We sequenced and characterized Drosophila mutants tan1 and tan3. The latter appears to be a mutant with normal expression in neural tissue but weak one in epidermis.

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► NBAD-hydrolase recycles neurotransmitters: dopamine, histamine and maybe others.
► Novel expression in epidermis and neural tissue is shown.
► NBAD-hydrolase activity is constitutive even in absence of NBAD-synthase activity.
► tan1 and tan3 mutants were characterized.