Two promoters differentially regulate testin gene. (A) Gene structure of testin (TES) gene. (B,C) Promoter activity for promoters of the TES gene in 16 tested cell types represented as a transformed firefly luciferase/Renilla luciferase ratio. (B) Promoter A shows activity in 12 of the 16 tissues but little activity in two brain cell lines, U87 and T98G. (C) Promoter B has significant activity only in U87 and T98G, both brain cell lines.