A set of 5 point mutations were introduced to the mouse Fgfr1 gene via homologous recombination: L423A and V429A in exon 8, Y463F in exon 9, Y766F in exon 17, and Y776F in exon 17. An in-frame 2xMyc epitope tag was placed at the 3' end of the last exon. Cre-mediated recombination removed a loxP-flanked neomycin cassette in exon 8. (J:101977)