SECRETION OF FUNCTIONAL RENILLA-RENIFORMIS LUCIFERASE BY MAMMALIAN-CELLS

The soft coral Renilla reniformis luciferase enzyme is a monomeric sol uble intracellular protein that is used increasingly as a marker of ge ne expression. Here the Renilla luciferase gene was engineered to enco de a protein product secreted by mammalian cells. The 5' end of the Re nilla luciferase gene was fused in frame with the 3' end of a short DN A sequence encoding the signal peptide from human interleukin-2 (IL-2) protein. This construct was cloned under transcriptional control of t he cytomegalovirus (CMV) promoter in a mammalian expression vector. Si mian COS-7 cells were transiently transfected with the construct, and light emission was measured from cell lysates and from cell culture me dia. The results of these experiments indicated that Renilla luciferas e was secreted as a functional enzyme by mammalian cells. The advantag es and disadvantages of secreted Renilla luciferase as a marker of gen e expression in comparison to other secreted protein markers are discu ssed. (C) 1997 Elsevier Science B.V.