Cloning of a calcium channel alpha 1 subunit from the reef-building coral,Stylophora pistillata

While the mechanisms of cellular Ca2+ entry associated with cell activation are well characterized, the pathway of continuous uptake of the large amou nt of Ca2+ needed in the biomineralization process remains largely unknown. Scleractinian corals are one of the major calcifying groups of organisms. Recent studies have suggested that a voltage-dependent Ca2+ channel is invo lved in the transepithelial transport of Ca2+ used for coral calcification. We report here the cloning and sequencing of a cDNA coding a coral al subu nit Ca2+ channel. This channel is closely related to the L-type family foun d in vertebrates and invertebrates. Immunohistochemical analysis shows that this channel is present within the calicoblastic ectoderm, the site involv ed in calcium carbonate precipitation. These data and previous results prov ide molecular evidence that voltage-dependent Ca2+ channels are involved in calcification. Cnidarians are the most primitive organisms in which a Ca2 channel has been cloned up to now; evolutionary perspectives on Ca2+ chann el diversity are discussed. (C) 1999 Elsevier Science B.V. All rights reser ved.