Figure 7. ZO-1 expression is unaffected by retinal conditioned medium.

Changes in ZO-1 expression were unrelated to junction permeability and were unaffected by conditioned medium. Immunoblots of proteins from cultures of E7 (A) and E14 (B) embryos. E14 retinal conditioned medium was added on day 1 to the indicated cultures. Total protein was extracted on the indicated day of culture and 15 µg per lane was immunoblotted with antibody 7445 to reveal ZO-1 and ZO-1 LP. The background is higher in (B), because longer exposures were required to detect a signal. The position of myosin (200 kDa) is indicated; beta-galactosidase (115 kDa) migrated off the bottom of the gel. (A) E7 RPE, 2 min exposure. (B) E14 RPE, 50 min exposure. (C) Densitometry of the immunoblots in panels (A and B). Qualitatively similar results were obtained in several experiments. Open symbols, ZO-1; closed symbols, ZO-1LP; squares, SF2; circles, conditioned medium.

C.