factor Sox10 (Liu et al., 1999). To confirm that the transcriptional activity of pSGB4SH, a β-gal-based system, is similar to that of the previous β4/luciferase constructs, transient transfections were carried out using the rat pheochromocytoma cell line, PC12 (Greene and Tischler, 1976). pSGB4SH was transfected into parallel cultures of PC12 cells with one set of cells being treated with NGF for 2 days following transfection and the other set being used as untreated controls. As shown in Figure 1D, there was a significant increase in β-gal activity following NGF treatment reflecting an increase in β4 promoter activity. These data are consistent with our previous work using the luciferase-based reporter vector (Hu et al., 1994; Liu et al., 1999) and indicated that the new construct was suitable for transgenic work.
