Fluorescence microscopy of HeLa cells expressing GFP and the R433K mALAS2 variant.

<p>From left to right for each row, the panels correspond to (1) brightfield, (2) green fluorescence, (3) red fluorescence, (4) superimposed green and red fluorescence, and (5) superimposed brightfield, green fluorescence, and red fluorescence images. (A) HeLa cells grown to confluence in culture medium with 100 mM glycine. (B) HeLa cells transfected with pIRES2-ZsGreen1 and grown to confluence in culture medium with 100 mM glycine. (C) HeLa cells transfected with pEF31, which expresses the R433K variant from the CMV promoter in the pIRES2-ZsGreen1 vector (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093078#pone-0093078-t001" target="_blank">Table 1</a>), and grown to confluence in culture medium with 100 mM glycine. (D) HeLa cells transfected with pEF31 and grown to subconfluence (<i>i.e.,</i> 80% confluence) in culture medium with 100 mM glycine. Pictures were obtained 24 hours after transfection and 18 hours after glycine supplementation. ZsGreen1 (green) is present throughout the cell, while PPIX (red) accumulates at the plasma membrane of cells expressing R433K and surrounding cells.