Identification and chromosomal localisation by fluorescence in situ hybridisation of human gene of phosphoinositide-specific phospholipase C beta(1)

Members of phosphoinositide-specific phospholipase C (PLC) families are cen tral intermediary in signal transduction in response to the occupancy of re ceptors by many growth factors. Among PLC isoforms, the type beta(1) is of particular interest because of its reported nuclear localisation in additio n 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 d ifferent stimuli implicate PLC beta(1) as an important enzyme for mitogen-a ctivated cell growth as well as for murine erythroleukaemia cell differenti ation. The above findings hinting at a direct involvement of PLC beta(1) in controlling the cell cycle in rodent cells, and the previously reported ma pping of its gene in rat chromosome band 3q35-36, a region frequently rearr anged in rat tumours induced by chemical carcinogenesis, prompted us to ide ntify its human homologue. By screening a human foetal brain cDNA library w ith the rat PLC beta(1) cDNA probe, we have identified a clone homologous t o a sequence in gene bank called KIAA 0581, which encodes a large part of t he human PLC beta(1). By using this human cDNA in fluorescence in situ hybr idisation 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 q 35-36 in rat and p12 in man. Since band 20p12 has been recently reported am plified and/or deleted in several solid tumours, the identification and chr omosome mapping of human PLC beta(1) could pave the way for further investi gations 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 interme diate in the control of the cell cycle. (C) 2000 Elsevier Science B.V. All rights reserved.