Todorčević et al. BMC Genomics 2010, 11:39 http://www.biomedcentral.com/1471-2164/11/39 Page 8 of 17 Figure 7 Cell lineage markers analyzed with real-time qPCR. PPARg - peroxisome proliferator-activated receptor g, MyoD - myogenic factor D, BMP4 - bone morphogenic protein 4, 1C. C/EBP - CCAAT/enhancer-binding proteins a, b and δ, LPL - lipoprotein lipase, FAS - fatty acid synthase. evidence of the pericytic identity of adipocytes’ precur- sors in our model since Tang et al. confirmed PPARg as a specific marker of the perivascular fraction in subcon- fluent aSVF [9]. Indeed, our finding of high levels of PPARg mRNA well before confluence contradicts the cell culture studies reviewed in [18] as the expression of C/EBPb and C/EBPδ predate the expression of PPARg and C/EBPa [17,18], which then activate adipocyte-spe- cific genes during terminal differentiation. This illus- trates the advantage of primary cell cultures, which offer possibilities to gain valuable insight into the early mole- cular events of adipogenic differentiation. Commitment of multipotent MSCs to the adipogenic lineage involves simultaneous inhibition of other mesenchymal lineages. Starting from day 6 we observed consistently decreased expression of MyoD, an early marker of the myogenic lineage. MyoD regulates the cell cycle in terminally differentiated myocytes by inducing CDK inhibitor p21, which irreversibly arrests prolifera- tion [43]. MyoD may play a similar role in mature adi- pocytes and in theory this could account for the increased expression at day 30. Activation of BMP4 from day 9 was an additional evidence for the inhibition of myogenesis. This growth factor equally promotes dif- ferentiation of the adipose, cartilage or bone lineages depending on the culture conditions [44,45]. Therefore, activation of BMP4 is necessary but not sufficient for the commitment of preadipocytes. PPARg is a master