MOLECULAR-CLONING AND EXPRESSION OF AN ADENYLYL-CYCLASE FROM XENOPUS-LAEVIS OOCYTES

We have cloned a cDNA that encodes a novel Xenopus laevis oocyte adeny lyl cyclase (xlAC) using oligonucleotides against conserved mammalian adenylyl cyclase regions. The isolated cDNA is 4372 bp long with an op en reading frame of 4065 nucleotides which encodes a protein of 1355 a mino acids. Comparison of the deduced amino acid sequence with previou sly cloned mammalian adenylyl cyclases shows a low identity, 19.7% wit h type 2 rat adenylyl cyclase and 24.2% with type 4 rat adenylyl cycla se, indicating that this Xenopus isoform represents a new member of th is protein family. Gene expression studies of the xlAC by reverse PCR showed that this gene is expressed in all oogenesis stages but not dur ing early embryogenesis. Expression of the xlAC in COS-7 cells resulte d in increased basal AC activity, that was stimulated by forskolin, Gp p(NH)p and aluminium fluoride, and was insensitive to calcium and calc ium-calmodulin (Ca2+-CaM). (C) 1997 Federation of European Biochemical Societies.