Distinct patterns of cAMP-dependent protein kinase gene expression in mouse brain

Abstract

In situ hybridization was used to localize cAMP-dependent protein kinase (PKA) mRNAs in the adult mouse CNS. The PKA holoenzyme contains two catalytic (C) subunits and a regulatory (R) subunit dimer. Our studies demonstrate expression of two isoforms of C (Cα and Cβ) and four isoforms of R (RIα, RIβ, RIIα, and RIIβ) in the CNS. mRNAs for Cα, RIα, and RIβ preferentially localize in the neocortex, caudate-putamen, hypothalamus, thalamus, and hippocampus. Hybridization with Cβ and RIIβ probes is clearly distinguished from the Cα-like pattern by a reduced level of hybridization in the thalamus and by a relative increase in expression in the dentate gyrus compared with cell layers CA1–3 in the hippocampus. RIIα transcripts are very specifically localized in the medial habenula. The differential expression of PKA subunit genes suggests that functional differences in cAMP responses within neural tissues may be mediated by the biochemical properties of specific PKA isoforms.