The Role of MRTF-A in Branching Morphogenesis of the Avian Lungs

Abstract

Branching morphogenesis of the embryonic chicken lung requires apical constriction, the contraction of the actomyosin network on the apical side of the airway epithelial cells of the primary bronchus, for the initial formation and growth of secondary bronchi. Myocardin-related transcription factor-A (MRTF-A) is part of a mechanotransduction pathway that leads to the regulation of actin levels in the cell. MRTF-A first localizes into the nucleus and then binds to serum response factor (SRF) to transcribe genes associated with actin polymerization. To better understand the role of MRTF-A, I used the MRTF-A inhibitor CCG-1423 to prevent MRTF-A from entering into the nucleus. With CCG-1423, I conducted experiments to determine its effects on the growth of secondary bronchi growth and the total number of secondary bronchi that form. I then performed different immunofluorescent stainings to determine how CCG-1423 and the inhibition of MRTF-A were affecting cell proliferation and apical constriction. Elucidating the intricate network of signaling pathways involved in branching morphogenesis of the lungs is crucial to develop solutions for lung diseases.