Exons 2-6 were replaced with a cassette encoding a farnysylated YFP fused to the 5-prime sequence of exon2 and an FRT-flanked neomycin resistance cassette, and subsequent flpe-mediated excision deleted the neomycin selection cassette. Although sequencing confirmed that the integrated YFPF is in-frame with the start site, no expression was detected by either endogenous fluorescence or antibody staining. Although this deletion is also in intron 1 of Sec1, Q-RT-PCR did not detect any reduction in Sec1 expression.