Figure 3: Comparison of 2 DE images of undifferentiated CSM14.1 cells (a) and of CSM14.1 cells after 28 days of differentiation (b). For spot visualization Coomassie-staining was used. Two groups of experimental gels (6 gels from day 0 and 6 gels from day 28) were registered to a reference gel chosen from day 0 gels. Spots showing a 2.5-fold larger or lower spot volume in 5 or 6 different gels of each group were considered up- or downregulated. Absent spots were defined as spots found in 5 or 6 gels of the day 28 group and not found in any gel of the day 0 group and the reference gel. In the reference gel 506 spots could be detected and 70.2% (±5.3) of the spots from the experimental gels day 0 could be matched onto the reference gel. In contrast, only 49.2% (±3.37) of the spots from the experimental gels day 28 found a match on the reference gel. Using the selection criteria as shown above, 27 spots were found upregulated in differentiated CSM14.1 cells, 24 spots downregulated, and 46 spots were detected as absent (i.e., only found in differentiated CSM14.1 cells). Via MALDI-TOF analysis 64 proteins could be identified.