Biology Reference
In-Depth Information
HUMAN
MOUSE
Antibody
(green)
Antibody
(red)
green
red
MOUSE
HUMAN
Sendai
Virus
green
red
HETERO
KARYON
TIME: ZERO
HETERO
KARYON
TIME: 40 min
FIGURE 9.12
The Frye-Edidin experiment. Cell cultures were obtained from a mouse and a human cell line.
Each cell type had different surface antigens. Fluorescent-labeled antibodies were obtained for each cell line. The
antibody for the mouse antigen was labeled with fluorescein and so appeared green, while the antibody for the
human antigen was labeled with rhodamine and so appeared red. The cells were fused with a Sendai virus
producing a heterokaryon that initially had one half of the mega-cell green and one half red. After 40 minutes the
red and green colors were totally mixed indicating membrane protein lateral diffusion.
membranes. This technique is referred to as fluorescence recovery after photobleaching or
FRAP (
Figure 9.14
).
FRAP had its beginnings in a 1976 paper by Axelrod et al.
[19]
. The technique requires
a high quality light microscope, a general low intensity light source, and a highly focused,
high intensity light, normally a laser. FRAP begins by uniformly labeling the surface of
