Nkx2 2

Western blots were generated by the semi-dry method. Protein lysates from cell lines were prepared using SIGMAFast protease inhibitor cocktail (Sigma). Proteins were transferred onto nitrocellulose membranes (Bio-Rad, München, Germany) and blocked with 5% dry milk powder dissolved in phosphate-buffered-saline buffer (PBS). The following antibodies were used: MSX1 (R & D Systems), alpha-Tubulin (Sigma), PDGFRB (R & D Systems), phospho-PDGFRB (Aviva Systems Biology, Eching, Germany), NKX2-2 (Aviva Systems Biology) and PITX1 (Abnova, Taipei, Taiwan). For loading control blots were reversibly stained with Poinceau (Sigma) and detection of alpha-Tubulin (TUBA) was performed thereafter. Secondary antibodies were linked to peroxidase for detection by Western-Lightning-ECL (Perkin Elmer, Waltham, MA, USA). Documentation was performed using the digital system ChemoStar Imager (INTAS, Göttingen, Germany). PDGFD and BMP4 were quantified in the medium by ELISA using according Quantikine ELISA kits from R & D Systems. Samples were obtained by harvesting supernatants of 1x10⁶ cells which were washed in PBS and subsequently incubated in 1 ml medium for 24 h.

Western blots were generated by the semi-dry method. Protein lysates from cell lines were prepared using SIGMAFast protease inhibitor cocktail (Sigma). Proteins were transferred onto nitrocellulose membranes (Bio-Rad, München, Germany) and blocked with 5% dry milk powder dissolved in phosphate-buffered-saline buffer (PBS). The following antibodies were used: alpha-tubulin (Sigma), NKX2-2 (Aviva Systems Biology, San Diego, CA, USA), ERK1 (Santa Cruz Biotechnology, Heidelberg, Germany), and phospho-ERK (Santa Cruz Biotechnology). For loading control blots were reversibly stained with Poinceau (Sigma) and detection of alpha-tubulin (TUBA) was performed thereafter. Secondary antibodies were linked to peroxidase for detection by Western-Lightning-ECL (Perkin Elmer, Waltham, MA, USA). Documentation was performed using the digital system ChemoStar Imager (INTAS, Göttingen, Germany).