Table 3

Immunogold Dimer Formation Associated with SR-BI-enriched Cell Surface Sites of SR-BI-V5 + SR-BI-cMyc Transfected Y1-BS1 Cells

Expt. no.

Total gold in region measured

Large + small heterodimer

Small + small homodimer

Large + large homodimer

Total dimers

Total* dimer gold

Dimer gold as percent of total gold

1

615

42

33

46

121

242

39%

2

1513

99

94

99

292

584

39%

3

756

53

85

32

170

340

45%

*Note: Since each dimer represents two gold particles, "total dimer gold" represents total dimers X 2. This number divided by the "total gold in the region" represents the percentage of total gold found as dimers.

Small 10 nm gold coupled to anti-mouse-IgG was used to identify V5 monoclonal antibody staining of the Y1-BS1 cells transfected with an SR- B1-V5 tag cDNA construct.

Large, 15 nm gold complexed with anti-rabbit IgG was used to identify cMyc polyclonal antibody staining of the Y1-BS1 transfected SR-BI-cMyc tag plasmid DNA. Close contact between gold particles was used to identify the 3 possible dimer combinations, and, as shown here, the numbers were similar (indicating reasonable levels of first and second antibody concentrations had been used to balance differences in antibody sensitivities and size of gold particles).

Large/small gold dimer combinations indicate that secondary antibodies representing anti-mouse IgG gold (V5 staining) and anti-rabbit IgG gold (cMyc staining) are present at the same cell site, and, as such, eliminate the possibility that random gold clustering in solution is responsible for the dimer-like formations.

Reaven et al. Nutrition & Metabolism 2006 3:43   doi:10.1186/1743-7075-3-43