GFP fluorescence in the transient expression assay for identification of the alternative first exons. Transgene expression regulated by several constructs containing regions upstream of the translation start codon of ol_pmp22 was observed as GFP fluorescence. (A-E) Dosal view of anterior of fish with the p11-0, p6.5-0, p3-0, p6.5-3 and p11-5 constructs, respectively. White arrowheads show GFP expressing morphologically identified Schwann cells. Bars: 200 μm. (F) The alternative first exons and exon2 of ol_pmp22 and constructs for the transient expression assay.