Effect of Tmsb4x knockout on TGF-ß/MRTF signaling

Myocardin-related transcription factors (MRTFs) are robust co-activator of Serum Reponse Factor, and regulate cell adhesion and motility by controlling the transcription level of cytoskeletal components. In tumor progression, MRTFs has been reported to contribute to metastatic potential. Previously, we reported thymosin-ß4 (Tß4, which is encoded by Tmsb4x gene) as an activator of MRTFs. Enhanced expression of Tß4 is frequently observed during tumor progression, and associated with poor prognosis. However, the relationships between MRTFs and Tß4 in tumor progression are largely unknown. Here we analyze the effect of Tß4 knockout on the transcription levels of MRTFs-target genes. In particular, we focused on their functions in TGF-ß signaling because both MRTFs and Tß4 are down-stream effectors of TGF-ß. Wild-type and Tmsb4x knockdown B16F1 cells were treated with 10 ng/ml of TGF-ß1 for 2 days. For the inhibition of MRTF signaling, cells were also treated with 10 µM MRTF inhibitor CCG1423.