Differential expression of the G protein beta(5) gene: Analysis of mouse brain, peripheral tissues, and cultured cell lines

A neurally expressed heterotrimeric G protein beta subunit, G beta(5), has been found to exhibit functional specialization with respect to its interac tions with effector targets and G alpha subunits. A splice Variant of G bet a(5) that contains an N-terminal 42-residue extension, G beta(5)-long, has been described in the retina. To define better the potential range of its s pecialized interactions, analysis of G beta(5) gene transcript and protein expression in mouse brain and other tissues and cell lines was performed, Q uantification by ribonuclease protection assay of G beta(5) transcript expr ession in the developing brain demonstrates a fivefold increase that occurs postnatally. Analysis of transcript expression by in situ hybridization an d ribonuclease protection assay indicates that the G beta(5) gene is differ entially expressed among multiple adult mouse brain regions, including the motor and occipital cortex, the olfactory bulb and associated rhinencephali c structures, hypothalamus, pontine cochlear nuclei, and Purkinje cells in the cerebellum, G beta(5) is also expressed in several cultured cell lines of neuroendocrine origin, including murine alpha T3-1 pituitary gonadotroph s and GT1-7 hypothalamic cells, and rat PC12 pheochromocytoma cells. Immuno blotting of tissue homogenates with antibodies to two peptides common to G beta(5) and G beta(5)-long confirmed expression of G beta(5) in multiple br ain regions and in spinal cord and expression of G beta(5)-long in retina. Taken together, these results suggest that the specialized molecular proper ties of G beta(5) have been adapted to diverse neural functions in the adul t brain.