Identification and chromosomal localisation by fluorescence in situ hybridisation of human gene of phosphoinositide-specific phospholipase C β1

Members of phosphoinositide-specific phospholipase C (PLC) families are central intermediary in signal transduction in response to the occupancy of receptors by many growth factors. Among PLC isoforms, the type beta(1) is of particular interest because of its reported nuclear localisation in addition to its presence at the plasma membrane. It has been previously shown that both the stimulation and the inhibition of the nuclear PLC beta(1) under different stimuli implicate PLC beta(1) as an important enzyme for mitogen-activated cell growth as well as for murine erythroleukaemia cell differentiation. The above findings hinting at a direct involvement of PLC beta(1) in controlling the cell cycle in rodent cells, and the previously reported mapping of its gene in rat chromosome band 3q35-36, a region frequently rearranged in rat tumours induced by chemical carcinogenesis, prompted us to identify its human homologue. By screening a human foetal brain cDNA library with the rat PLC beta(1) cDNA probe, we have identified a clone homologous to a sequence in gene bank called KIAA 0581, which encodes a large part of the human PLC beta(1). By using this human cDNA in fluorescence in situ hybridisation on human metaphases, it has been possible to map human PLC beta(1) on chromosome 20p12, confirming the synteny between rat chromosome 3 and human chromosome 20 and providing a novel locus of homology between bands q35-36 in rat and p12 in man. Since band 20p12 has been recently reported amplified and/or deleted in several solid tumours, the identification and chromosome mapping of human PLC beta(1) could pave the way for further investigations on the role exerted both in normal human cells and in human tumours by PLC beta(1), which has been shown to behave as a key signalling intermediate in the control of the cell cycle. (C) 2000 Elsevier Science B.V. All rights reserved.