The bone morphogenetic protein (BMP) signaling network, comprising evolutionary conserved BMP2/4/Decapentaplegic (Dpp) and Chordin/Short gastrulation (Sog), is widely utilized for dorsal-ventral (DV) patterning during animal development. A similar network is required for posterior crossvein (PCV) formation in the Drosophila pupal wing. Although both transcriptional and post-transcriptional regulation of co-factors in the network appears to give rise to tissue-specific and species-specific properties, their mechanisms are incompletely understood. In Drosophila, BMP5-8 type ligands, Screw (Scw) and Glass bottom boat (Gbb), form heterodimers with Dpp for DV patterning and PCV development, respectively. Sequence analysis indicates that the Scw ligand contains two N-glycosylation motifs; one being highly conserved between BMP2/4 and BMP5-8 type ligands, and the other being Scw ligand-specific. Our data reveal that N-glycosylation of the Scw ligand boosts BMP signaling both in cell culture and in the embryo. In contrast, N-glycosylation modifications of Gbb or Scw ligands reduce the consistency of PCV development. These results suggest that tolerance for structural changes of BMP5-8 type ligands is dependent on developmental constraints. Furthermore, gain and loss of N-glycosylation motifs in conserved signaling molecules under evolutionary constraints appear to constitute flexible modules to adapt to developmental processes.
- Received September 2, 2015.
- Accepted August 17, 2016.