Quantitative real-time polymerase chain reaction measurement of regulators of G-protein signaling mRNA levels in mouse tissues.

Regulators of G-protein signaling (RGS) play a critical role in G-protein-coupled receptor signaling in mammalian cells. RGS proteins are GTPase-accelerating proteins (GAPs) for alpha subunits of heterotrimeric G proteins of the Gi and Gq class. RGS GAPs can modulate the frequency and duration of G-protein signaling and may constitute a new family of therapeutic targets. Identifying the tissue distribution and cellular localization of RGS proteins has been hindered by the lack of effective antibodies for immunodetection. The measurement of mRNA levels for RGS proteins, however, can provide insight into their tissue specificity and regulation. This article describes the use of a highly sensitive and rapid method for measuring RGS mRNA in mouse tissues. This quantitative real-time polymerase chain reaction method is established for the 19 reported mouse RGS genes and is used to study the tissue distribution of the R4 family of RGS genes and the diurnal regulation of RGS16 in mouse liver.