Localization of mRNAs encoding the alpha-subunits of signal-transducing G-proteins within rat brain and among...

The sequence of the mRNAs which encode the alpha-subunits of the signal-transducing G-proteins Gs, Go and two forms of Gi (termed Gi1 and Gi2) have recently been reported. Based on rat sequences we prepared oligodeoxynucleotide probes for measurement of these mRNAs in rat brain and peripheral tissues. The relative abundance of these mRNA species in brain was Gs greater than Go approximately Gi2 greater than Gi1. The Gs and Gi2 mRNAs had somewhat lower levels in heart, kidney and liver than in brain, and Go and Gi1 mRNAs were not detected in the peripheral tissues. Using in situ hybridization we localized each of these mRNAs within slices of the rat brain. The patterns of distribution of Gs and Gi2 mRNA were very similar, but very different from that of Go and Gi1 mRNA. These data illustrate that receptor-effector coupling G-proteins are regionally specialized in their expression. This regional specialization may reflect a selective coupling of individual G-proteins with the various neurotransmitter receptors and effector pathways.