Figure 4.

In vivo function of GCM. (A) Various luciferase reporter plasmids were transfected into U138 glioblastoma cells in the absence (open bars) or presence (filled bars) of cotransfected full-length GCM. pTATAluc contained only a minimal promoter, whereas all other reporter plasmids carried additional binding sites for transcription factors. siteAluc and 6xoct luc contained one or six binding sites for POU-domain proteins; gbs luc constructs had either one, three, or six copies of a GCM-binding site inserted in front of the minimal promoter. (B) The 3xgbs luc reporter was transfected together with empty expression plasmid (−) or various GCM expression plasmids (GCM fl, GCM 421, GCM 338, GCM 253, and GCM 171) into U138 cells. Luciferase activities in extracts from transfected cells were determined in three independent experiments, each performed in duplicate. Data are presented as fold inductions that were calculated for each reporter plasmid by comparing luciferase activities to values from cells that were transfected with reporter plasmid and empty CMV expression plasmid. Note the logarithmic scale of the y axis in A.