Intracellular localization of Reelin in COS cells. After transfection with pCrlM encoding full-length Reelin under the control of the CMV promoter, COS cells were fixed, permeabilized, and incubated for 1 hr with the primary CR-50 antibody and for an additional 30 min with FITC-tagged anti-mouse secondary antibody.A, Fluorescent image of a cell expressing Reelin (80× magnification). B, Phase-contrast image of the same cell field.