Abstract
The Twisted gastrulation (Tsg) proteins are modulators of bone morphogenetic protein (BMP) activity in both vertebrates and insects. We find that the crossveinless (cv) gene of Drosophila encodes a new tsg-like gene. Genetic experiments show that cv, similarly to tsg, interacts with short gastrulation (sog) to modulate BMP signalling. Despite this common property, Cv shows a different BMP ligand specificity as compared with Tsg, and its expression is limited to the developing wing. These findings and the presence of two types of Tsg-like protein in several insects suggest that Cv represents a subgroup of the Tsg-like BMP-modulating proteins.
