Surface expression and current amplitude as a function of MEC-2 cRNA. (A) Surface expression of myc∷MEC-4d in oocytes coexpressing myc∷MEC-4d, MEC-10d, MEC-2, and MEC-6 (top). The amount of MEC-2 cRNA is indicated below each lane; U indicates uninjected (control) oocytes. Relative surface expression as a function MEC-2 cRNA (bottom), normalized to density with 1 ng MEC-2 cRNA per oocyte. Data represent the results of three independent Western blots. Nonspecific bands are observed in all blots and are visible in uninjected cells. (B) Amiloride-sensitive currents recorded from oocytes analyzed in parallel with those used for Western blotting in A. Stars indicate significance P < 0.01 (Student's t test). Smooth line is fit to the data according to: I = I₀ + (I_max − I₀)(1 + [MEC-2 cRNA]/EC₅₀)⁻¹. The EC₅₀ is 2.8 ng, I_O = 0.48 μA.