Consequences of over-expression of rat Scavenger Receptor, SR-BI, in an adrenal cell model

Nutrition & Metabolism

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 hetero dimer	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.

ISSN: 1743-7075