MTBR-YFP aggregates transfer between co-cultured cells. A,
cells were transfected separately with mCherry or MTBR-YFP. The two cell
populations were either mixed immediately prior to analysis or co-cultured for
24 h. Flow cytometry was used to quantify dual positive cells (10,000 cells
sorted per condition). B, quantification of flow cytometry revealed
that 0.5% of cells scored positive for mCherry and YFP (upper right
quadrant of cell plot) when cells were simply mixed prior to sorting,
versus 1.5% of cells that scored dual positive when cells were
co-cultured for 24 h, indicating transfer of MTBR-YFP between cells.
*, p < 10-5 (unpaired t test,
n = 4, 10,000 cells sorted per experiment). C, dual positive
cells were collected via FACS, fixed, and mounted. A MTBR-YFP inclusion
(white arrowhead) is visible within an mCherry-expressing cell.
Scale bar, 10 μm.