Functional roles of C/EBP¿ and SUMO.modification in lung development

Abstract

CCAAT enhancer binding protein alpha (C/EBPá) is a transcription factor regulating the core aspects of cell growth and differentiation. The present study investigated the level and functional role of C/EBPá during the development of the rat lung. C/EBPá protein exhibits a dynamic expression pattern. The correlation between the expression of C/EBPá protein and the content of glycogen during lung maturation was analyzed to understand the function of C/EBPá in lung differentiation. The high expression of C/EBPá coincides with the reduction of glycogen in the fetal lung. In addition, the authors identified that changes in the level of C/EBPá are associated with the secretion of pulmonary surfactant. C/EBPá is modified by small ubiquitin-related modifier (SUMO) post-translationally. The results of double immunofluorescence staining and immunoprecipitation demonstrated that SUMO-modified C/EBPá was present in the lung. The sumoylated C/EBPá gradually decreased during lung differentiation and was negatively correlated with pulmonary surfactant secretion, thereby suggesting that the SUMO modification may participate in C/EBPá-mediated lung growth and differentiation. These results indicated that C/EBPá played a role in lung development and provided the insight into the mechanism underlying SUMO-modification.