EXPRESSION OF HETEROLOGOUS PROTEINS IN CULTURED RAT HIPPOCAMPAL-NEURONS USING THE SEMLIKI FOREST VIRUS VECTOR

The Semliki Forest virus expression vector (Liljestrom and Garoff: Bio /Technology 9:1356-1361, 1991) was tested in cultured rat hippocampal neurons using two Madin-Darby canine kidney (MDCK) cell membrane-assoc iated proteins as reporters: rab8, a small GTPase involved in post-Gol gi vesicle transport, and VIP21, an integral membrane protein of caveo lae, trans-Golgi network, and post-Golgi vesicles. Expression of the c -myc epitope-tagged proteins was visualized by immunofluorescence micr oscopy. The proteins were first detected in neurons after 3-4 hr infec tion by the recombinant viruses. The infection efficiency on neurons w as high: after 6 hr infection at a multiplicity of one, 50-60% of the cells expressed the reporter proteins. The neurons tolerated the infec tion well up to 8 hr. Their polarized organization was not disturbed, as judged from morphology and from distribution of the dendritic MAP2 and axonal synaptophysin marker proteins. The Semliki Forest virus vec tor thus seems suitable for short-term expression of proteins in cultu red neurons.