IMMUNOCHEMICAL AND IMMUNOHISTOCHEMICAL LOCALIZATION OF THE G PROTEIN-GI1 IN RAT CENTRAL NERVOUS TISSUES

Antisera were raised in rabbits against purified α subunit of G protein G11 (G11α) and also against a synthetic decapeptide corresponding to a sequence of G11α. Antibodies in both antisera were purified with a G11-coupled Sepharose column, but purified anti-G11α protein antibodies still reacted equally with both G11α and G13α, while anti-G11α peptide antibodies reacted principally with Gna. Using these antibodies, an enzyme immunoassay method for the quantification of Gna was developed. The assay system consisted of polystyrene balls with immobilized anti-G11α protein antibody F(ab′)2 fragments and the anti-G11α peptide antibody Fabα fragments labeled with β-D-galactosidase from Escherichia coli. The minimum detection limit of the assay was 25 ftnol of G11α, and it did not cross-react with G12α, Goα, or γγ. Samples from various regions of the rat central nervous system were homogenized in a 2% sodium cholate solution, and the concentration of G11α in each extract was determined. G11α was detected in all the regions, and the highest concentration was found in the olfactory bulb. Immunohistochemical study showed that G11 was mainly localized in the neuropil. © 1990 Copyright, 1990 by the Journal of Biochemistry.