Expression of sprouty2 during early development of the chick embryo is coincident with known sites of FGF signalling

The Drosophila sprouty protein is a recently-identified intracellular modul ator of FGF and EGF receptor tyrosine kinase activity which antagonises ras /MAP kinase signalling. In a differential display analysis to identify gene s involved in patterning the mid/hindbrain region of the chick neural tube, we have identified a sprouty orthologue, sprouty2. Here we report expressi on of sprouty2 transcripts in the developing chick embryo. We find a close correlation with known sites of FGF activity but little correlation with ex pression patterns of members of the EGF family. Initially, transcripts are associated with the primitive streak. During the period of neural tube patt erning expression is detected in the anterior neuropore, in the isthmic reg ion and in neural plate and posterior spinal cord. Transcripts are also det ected in the otic placode, tail bud, mesoderm of the branchial arches, semi tic myotome. retina, limb buds and gut mesenchyme; all known sites of FGF a ction. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.