FIG. 6.
Immunogold localization of P12CA3 expressed by adenovirus vector (A and B) and nsP3 or nsP1 in SFV infection (C and D). HeLa cells were infected with adenovirus 12CA3 or SFV and fixed with PLP fixative for 2 h at 28 or 5 h p.i., respectively. Proteins were visualized by treating saponin-permeabilized cells with anti-nsP3 (A, B, and C) or anti-nsP1 (D) rabbit antiserum and nanogold-conjugated Fab fragments. P12CA3 was seen in patches at the plasma membrane (A) and on the outer surface of electron-lucent cytoplasmic vesicles (marked with an asterisk in panel B). In SFV-infected cells nsP1 and nsP3 were on the cytoplasmic side of the limiting membrane of CPVs (C and D) and in patches at the plasma membrane (C). Note that some spherules remained intact even after saponin treatment (arrows in D). Arrows indicate areas positive for immunostaining. Bars, 500 nm (A and D), 200 nm (B), and 2 μm (C). PM, plasma membrane; N, nucleus.