MRTFA regulates bone marrow MSCs fate commitment via regulating TAZ/YAP transcriptional activity. WT and MRTFA KO bone marrow stromal cells were sorted with MACS magnetic beads to amplify the mesenchymal stem cells population. Sca1 positive and CD45 negative population of bone marrow stromal cells were isolated and harvested for RT-PCR to measure stem cell markers, osteogenic genes, and TAZ/YAP target genes (A). p-values were determined by paired t-test analysis of KO and control littermates. C3H10T1/2 cell lines over-expressing MRTFA and vector controls were seeded at different densities (100%, 75%, 50% and 30% confluence) and harvested after attaching for RT-PCR to measure the mRNA levels of TAZ/YAP target genes (B). WT and MRTFA KO Scal1+ CD45-bone marrow stem cells were plated and stained with phallodin, SMA antibody and DAPI (C) (scale Bar = 0.04 mm). A schematic model of how MRTFA inhibits adipogenesis and enhances osteogenesis is shown in (D). MRTFA is regulated by actin cytoskeleton dynamics through RhoA-Rock signaling pathway. Data are expressed as mean ± SEM (n = 3). *p < 0.05; **p < 0.01.