PHOSPHOLIPASE-C CDNAS FROM SPONGE AND HYDRA - ANTIQUITY OF GENES INVOLVED IN THE INOSITOL PHOSPHOLIPID SIGNALING PATHWAY

To know whether or not the set of genes involved in the inositol phosp holipid signaling pathway already existed in the early evolution of an imals, me carried out cloning of cDNAs encoding phospholipase Cs (PLCs ) from Ephydatia fluviatilis (freshwater sponge) and Hydra magnipapill ata strain 105 (hydra), We isolated two PLC cDNAs, PLC-PS and PLC-gamm a S, from sponge and three cDNAs, PLC-beta H1, PLC-beta H2, and PLC-de lta H, from hydra, From the domain organization and the divergence pat tern in the PLC family tree, the sponge PLC-PS and PLC-gamma S and the hydra PLC-GH are possibly homologous to the vertebrate PLC-beta, PLC- gamma and PLC-delta subtypes, respectively. A detailed phylogenetic an alysis suggests that the hydra PLC-beta H1 and PLC-beta H2 are homolog s of the vertebrate PLC-beta 1/2/3/ Drosophila PLC21 and the vertebrat e PLC-beta 4/Drosophila norpA, respectively. A phylogenetic analysis o f the PLC family and the protein kinase C (PKC) family, together with that of the C protein alpha subunit (G alpha) family, revealed that th e origin of the set of genes G alpha q, PLC, PKC involved in the inosi tol phospholipid signaling pathway is very old, going back to dates be fore the parazoan-eumetazoan split, the earliest branching among extan t animal phyla, (C) 1998 Federation of European Biochemical Societies.