Figure 4.

β_1C integrin expression increases TSP1 mRNA and protein levels in β₁–null GD25 cells. A, β_1C- and β_1A-GD25 transfectants were induced to express β_1C or β_1A and processed for cDNA array expression analysis. The arrows indicate the spots corresponding to TSP1 cDNA or an another gene, which is downregulated (shown as **) in β_1C-expressing cells. Similar results were obtained in two separate experiments. B, β_1C-GD25 transfectants (clones C1 and C2) were cultured as described above. Cells were lysed and immunoblotted using Ab to TSP1 or ERK1. C, β_1C-GD25 (clones C1 and C2) or β_1A-GD25 (clones A1 and A2) transfectants induced to express β_1C or β_1A, were detached and analyzed by FACS using either TS2/16 or 12CA5. The table summarizes the results of the FACS analysis.