Co-localization of I-2 and tubulin in ARPE-19 cells. ARPE-19 cells at sub confluent density were fixed and stained for I-2 (A, green) and gamma-tubulin (C, red), and visualized by laser scanning confocal microscopy (merged image in B). Scale bar = 20 micron. ARPE-19 cells 48 hrs after confluence were fixed and stained for I-2 (D, green) and acetylated tubulin (F, red) with merged image in E. Compressed Z-stack of confocal optical sections is displayed to show the primary cilia. Scale bar = 20 micron. (G) Wide-field microscopic image to show localization of basal body (green, gamma-tubulin staining) and cilium (orange, acetylated-tubulin staining) in a confluent ARPE-19 cell. Scale bar = 25 micron. (H) Wide-field image to show the localization of endogenous I-2 (green), gamma-tubulin (orange) and nucleus (blue) in confluent ARPE-19 cells. Scale bar = 25 micron.