Figure 7

Proliferation studies for Hoxc-8 transgenic cells. From the data in Figure 6, the proportion of cells in each phase of the cell cycle can be estimated, and a representative graph is shown in Panel A (turquoise: G-phase; green: G₂/M-phase; pink: S-phase). With increasing time of incubation, BrdU incorporation increases, labeling cells that actively proliferate. After 24 hours, up to 40% of cells have entered the DNA synthesis phase of the cell cycle. Panel B shows the proportion of chondrocytes in S phase in correlation to Hoxc-8 transgene expression level. The Hoxc-8 transgene is not expressed (REF) in TR only cells (dark and light green), moderately expressed in cells from animals with TA/+ TR/+ (light blue) and TA/+ TR/TR (dark blue) genotype (REF, REF) and more strongly expressed in cells from TA/TA TR/+ (pink) and TA/TA TR/TR (red) animals (REF, REF). Similar fractions of cells are in S-phase in all samples by 24 hours, and the rate of entry into S-phase (slope of curves) is very similar, indicating that cells of all genotypes exhibit proliferative capacity irrespective of expression of the Hoxc-8 transgene.