Expression of EGFP derivative fusion proteins. Membranes from
CHO-K1 cells stably expressing
Gal-T21–52-HA-ECFP (33.5 kDa, lane 1) or
GalNAc-T1–27-EYFP (30.3 kDa, lane 3) or both fusion
proteins (lane 2) were subjected to SDS/PAGE in the presence
(A) or in the absence (B) of
2-mercaptoethanol and Western blotted with anti-GFP antibody. Arrows in
B mark the positions of homodimers, and an asterisk
marks the expected position of the band corresponding to heterodimers.
(C) Lysates from single
Gal-T21–52-HA-ECFP (lane 1) and from double
Gal-T21–52-HA-ECFP and
GalNAc-T1–27-EYFP (lanes 2 and 3) transfectants were
immunoprecipitated (ip) with anti-HA (lanes 1 and 2) or
with anti-GFP (lane 3) antibodies, subjected to SDS/PAGE, and Western
blotted with anti-GFP antibody. (D) Lysates from single
Gal-T21–52-HA-ECFP (lane 1) and from double
Gal- T21–52-HA-ECFP and
ManII1–76-EYFP (lanes 2 and 3) were immunoprecipitated
with anti-HA (lanes 1 and 2) and with anti-GFP (lane 3)
antibodies, subjected to SDS/PAGE, and Western blotted with anti-GFP
antibody. (E) Visualization of
Gal-T21–52-HA-ECFP, endogenous
ManII, and GalNAc-T1–27-EYFP. Cells were fixed,
immunostained for ManII, and observed under the fluorescence microscope
using the filter for EYFP (GalNAc-T), rhodamine (ManII), and ECFP
(Gal-T21–52). Bar, 20 μm.