Article An Evolutionary Perspective of Dopachrome Tautomerase Enzymes in Metazoans Umberto Rosani 1,2,*, Stefania Domeneghetti 1, Lorenzo Maso 1, K. Mathias Wegner 2 and Paola Venier 1,* 1 Department of Biology, University of Padova, Padova, 35121, Italy;
[email protected] (S.D.);
[email protected] (L.M.) 2 Alfred Wegener Institute (AWI)—Helmholtz Centre for Polar and Marine Research, Wadden Sea Station Sylt, List auf Sylt25992, Germany;
[email protected] * Correspondence:
[email protected] (U.R.);
[email protected] (P.V.) Received: 16 May 2019; Accepted: 24 June 2019; Published: 28 June 2019 Abstract: Melanin plays a pivotal role in the cellular processes of several metazoans. The final step of the enzymically-regulated melanin biogenesis is the conversion of dopachrome into dihydroxyindoles, a reaction catalyzed by a class of enzymes called dopachrome tautomerases. We traced dopachrome tautomerase (DCT) and dopachrome converting enzyme (DCE) genes throughout metazoans and we could show that only one class is present in most of the phyla. While DCTs are typically found in deuterostomes, DCEs are present in several protostome phyla, including arthropods and mollusks. The respective DCEs belong to the yellow gene family, previously reported to be taxonomically restricted to insects, bacteria and fungi. Mining genomic and transcriptomic data of metazoans, we updated the distribution of DCE/yellow genes, demonstrating their presence and active expression in most of the lophotrochozoan phyla as well as in copepods (Crustacea). We have traced one intronless DCE/yellow gene through most of the analyzed lophotrochozoan genomes and we could show that it was subjected to genomic diversification in some species, while it is conserved in other species.