Figure 1. RT–PCR to detect the mRNA levels for the catalytic subunits of PP-1α, PP-1β, PP-2Aα, and PP-2Aβ in the retina, lens epithelium, lens fiber, and cornea of the mouse eye. RT–PCR was conducted as previously described [13]. The primers used in the present studies are described in Table 1. The PP-1 or PP-2A primers and the primers for β-actin were added to the reactions at the same time. The 397 bp DNA band for the PP-1α mRNA, the 463 bp DNA band for PP-1β mRNA, the 468 bp DNA band for the PP2Aα mRNA, and the 392 bp DNA band for PP-2Aβ mRNA were expressed at the highest levels in the retina, at reduced levels in the cornea, and at much lower levels in the lens epithelium and fiber cells. In addition, PP-1β was hardly detectable in the lens fiber cells. As an internal control, a β-actin DNA band of 242 bp is also included as comparison.