Molecular cloning and expression profile of Xenopus calcineurin A subunit

We have cloned a cDNA encoding a catalytic subunit of calcineurin (CnA) exp ressed in Xenopus oocytes. The deduced amino acid sequence indicates 96.3% and 96.8% identities with the mouse and human CnA alpha isoforms, respectiv ely. Xenopus CnA (XCnA) RNA and protein are expressed as maternal and throu ghout development. Recombinant XCnA protein interacted with calmodulin in t he presence of Ca2+. Deletion of calmodulin binding domain and auto-inhibit ory domain revealed calcium independent phosphatase activity, thereby showi ng that XCnA is likely to be modulated by both calmodulin and calcium. (C) 2000 Elsevier Science B.V. All rights reserved.