Fig. 4.

Characterization of the E1-b promoter region and EPHX1 expression in human cell lines. A, PCR genotyping of Alu insertion polymorphism in A549, HepG2, and 293T cells. The DNA fragment between -2428 and -1305 of E1-b was specifically amplified from genomic DNA demonstrating the presence of the 2xAlu insertion in 293T cells but not A549 or HepG2 cells. B, real-time PCR was performed with RNA obtained from the respective cell lines. The data shown depict means and S.D. values derived from two separate experiments, each performed in triplicate. The 293T cells exhibited a significantly lower level of EPHX1 E1-b transcript expression compared either with HepG2 or A549 cells (**, p < 0.01). C, Western immunoblot blot analysis assessing corresponding EPHX1 protein levels.