FIG. 3.

Stable expression of filamentous and nonfilamentous GFP-actin in PK15 epithelial cell lines. Expression of GFP-F-actin (filamentous) or the GFP-G-actin (globular) fusion proteins in PK15 cells. (A) Flow cytometric analysis of 10,000 nonfixed PK15 cells or cells from lines expressing similar levels of either GFP-F-actin (cell line 74) or GFP-G-actin (cell line 52). These lines were isolated following several rounds of fluorescence-activated cell sorting and expansion. (B) Cell lysates of PK15 cells and the cell lines were analyzed by Western blot analysis using monoclonal antibodies to β-actin and GFP. (C) Monolayers of PK15 cells (a) and cell lines expressing similar levels of GFP-F-actin (b) or GFP-G-actin (c) were grown on glass coverslips. Cells were fixed and stained for filamentous actin with rhodamine-conjugated phalloidin (red) and, along with GFP autofluorescence (green), imaged by confocal microscopy.