Carbonic anhydrases (CA) are zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide to bi- carbonate. In the sea urchin, CA has a role in the formation of the calcitic skeleton during embryo development. Here, we report a newly identified mRNA sequence from embryos of the sea urchin Paracentrotus lividus, referred to as Pl-can. The complete coding sequence was identified with the aid of both EST databases and experimental procedures. Pl-CAN is a 447 aa-long protein, with an estimated molecular mass of 48.5 kDa and an isoelectric point of 6.83. The in silico study of functional domains showed, in addition to the alpha type CA-specific domain, the presence of an unexpected glycine- rich region at the N-terminal of the molecule. This is not found in any other species described so far, but probably it is restricted to the sea urchins. The phylogenetic analysis indicated that Pl- CAN is evolutionarily closer to human among chordates than to other species. The putative role(s) of the identified domains This paper is dedicated to the memory of Valeria Matranga who did not live to see her work published. Electronic supplementary material The online version of this article (doi:10.1007/s10126-016-9701-0) contains supplementary material, which is available to authorized users. is discussed. The Pl-can temporal and spatial expression pro- files, analyzed throughout embryo development by compara- tive qPCR and whole-mount in situ hybridization (WMISH), showed that Pl-can mRNA is specifically expressed in the primary mesenchyme cells (PMC) of the embryo and levels increase along with the growth of the embryonic skeleton, reaching a peak at the pluteus stage. A recombinant fusion protein was produced in E. coli and used to raise specific anti- bodies in mice recognized the endogenous Pl-CAN by Western blot in embryo extracts from gastrula and pluteus.
