Figure 4

STRING analysis of the cluster 6 from the parabolic flight experiment. Chondrocytes were fixed after parabola 1 and 31 during a parabolic flight. In parallel, corresponding 1 g control samples were prepared. K-mean clustering of the resulting microarray data revealed 6 clusters of differentially expressed genes. Clusters 1–5 revealed mostly unspecific transcriptionally active genes, while cluster 6 showed a strong dominance by anti-apoptotic and cell-proliferative transcripts. Possible interactions of the corresponding proteins were visualized using the STRING software and genes involved in anti-apoptosis and cell proliferation were highlighted with white and black circles, respectively.