Fig. 6. Binding of Bd-cys preparations and anti-GABAA-subunit antibodies to GABAA-expressing oocytes.
A: GABAA-ρ1-expressing oocyte with anti-GABAA-ρ1, Bd-cys-S-PEG3400-biotin and streptavidin-DyLight 488 (column 1) or with Bd-cys-S-PEG3400-biotin and streptavidin-DyLight 488 only (column 2). Column 3: non-expressing oocyte with same treatment as in column 1. B: α1β2γ2 GABAA-expressing oocyte with anti-GABAA-α1, Bd-cys-S-PEG3400-biotin and streptavidin-DyLight 488 (column 1) or with Bd-cys-S-PEG3400-biotin and streptavidin-DyLight 488 only (column 2). Column 3: non-expressing oocyte with same treatment as in column 1. C: GABAA-ρ1-expressing oocyte with anti-GABAA-ρ1 and FL-labeled Bd-cys dimer (column 1) or with FL-labeled Bd-cys dimer only (column 2). Column 3: non-expressing oocyte with same treatment as in column 1. D: α1β2γ2 GABAA-expressing oocyte with anti-GABAA-α1 and FL-labeled Bd-cys dimer (column 1) or with FL-labeled Bd-cys dimer only (column 2). Column 3: non-expressing oocyte with same treatment as in column 1. Similar microscope acquisition settings were used for all conditions. For visual clarity, a fixed adjustment of brightness and contrast was applied to all images of C and D. Scale bar = 150 µm. The data show that the binding of Bd-cys-S-PEG3400-biotin (A-B) and of FL-labeled Bd-cys dimer (C-D) to the oocyte surface membrane depends on both the expression of GABAA receptor (GABAA-ρ1 in A and C; α1β2γ2 GABAA in B and D) and the presence of the cognate antibody.
