FGFR1 is an important signalling molecule during embryogenesis and in adulthood. FGFR1 mutations in human may lead to developmental defects and pathological conditions, including cancer and Alzheimers disease. Here, we describe cloning and expression analysis of the zebrafish fibroblast growth factor receptor 1 (fgfr1). Initially, fgfr1 is expressed in the adaxial mesoderm with transcripts distinctly localised to the anterior portion of each half-somite. Hereupon, fgfr1 is also strongly expressed in the otic vesicles, branchial arches and the brain, especially at the midbrain-hindbrain boundary (MHB). The expression patterns of fgfr1 and fgf8 are strikingly similar and knock-down of fgfr1 phenocopies many aspects observed in the fgf8 mutant acerebellar, suggesting that Fgf8 exerts its function mainly by binding to FgfR1. ; Steffen Scholpp, Casper Groth, Claudia Lohs Michael Lardelli and Michael Brand ; The original publication can be found at www.springerlink.com