Blimp-1 mediates tracheal lumen maturation in Drosophila melanogaster

The specification of tissue identity during embryonic development requires precise spatiotemporal coordination of gene expression. Many transcription factors required for the development of organs have been identified and their expression patterns are known; however, the mechanisms through which they coordinate gene expression in time remain poorly understood. Here we show that hormone-induced transcription factor Blimp-1 participates in the temporal coordination of tubulogenesis in Drosophila melanogaster by regulating the expression of many genes involved in tube maturation. In particular, we demonstrate that Blimp-1 regulates the expression of genes involved in chitin deposition and F-actin organization. We show that Blimp-1 is involved in the temporal control of lumen maturation by regulating the beginning of chitin deposition. We also report that Blimp-1 represses a variety of genes involved in tracheal maturation. Finally, we reveal that the kinase Btk29A serves as a link between Blimp-1 transcriptional repression and apical extra-cellular matrix organization.