Figure 1

Design for the microarray study on BMP6 induced osteoblast differentiation. Human MSC cells were pre-cultured for 4 days and subsequently treated with BMP6 for 0 hours, 8 hours, 24 hours, and 96 hours. These four time points correspond to four phenotypic groups, of control, preosteoblast (no mineralization), (sub-maximal) mineralization, and maximal mineralization at 14 days (18 days in total). Cells were harvested at 8 hours, 24 hours, 96 hours and 10 days for microarray profiling. Mineralization level was quantified at 14 days by Alizarin Red S staining (right column). GAGE was applied to infer the most differentially expressed pathways or gene sets between the matched samples with or without BMP6 at different time points. At time points corresponding to 8, 24 and 96 hours, GAGE compares between only two sample conditions. At the 10 day time point, GAGE compares between two mineralized conditions versus two non-mineralized conditions.