Figure 7.

High-level transient overexpression of Cx26 switches the site of onset of connexon assembly to the ER. HepG2 cells were transiently transfected with one of two Cx26-encoding plasmids: a CMV-driven construct with an intact polyA tail (lanes 1–4) or a SV40-driven construct in which the polyA tail had been deleted that expressed ∼60-fold lower levels of Cx26 protein (lanes 5–8). On day 2 after transfection, the cells were labeled with [³⁵S]methionine for 4 h at 37°C in either the absence (− BFA) or presence (+ BFA) of BFA. TX-100–soluble lysates were prepared and either cross-linked with EGS (+) or mock cross-linked (−) before immunoprecipitation of Cx26 and analysis by SDS-PAGE.