Fig. 3. Characterization of the by mutant phenotype. (A) A schematic drawing of the by genomic locus and the genomic structures of the by mutant alleles. ex10, by^ex10; ex49, by^ex49. (B) Comparison of the severity of the blistered wing phenotype between different by mutants. (C) Determination of expression levels of by transcript in various by mutant alleles using RT-PCR method. `a' represents 5' region of the by gene (shown in A). Ribosomal protein 49 (Rp49) was used as an internal control. RT products were amplified 28 times to detect `a' region, and 25 times to detect Rp49 levels in PCR reactions. (D) The by loss-of-function mutants exhibited decreased hatching rates from eggs. Black circles and triangles represent wild type and by^ex10, respectively. White squares and triangles represent by² and by^ex49, respectively. E, egg; L1, first instar larva; L2, second instar larva; L3, third instar larva; P, pupa; A, adult.