RGS7
Regulator of G-protein signaling 7 (RGS7)
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The abundant expression of RGS (regulator of G-protein signalling) proteins in neurons, together with their modulatory function on G-protein-dependent neurotransmission, provides the basis for cellular adaptation to sensory inputs. To identify the molecular mechanism involved in the sensory experience-induced neural development, we performed a systematic survey of the localization of mRNAs encoding three subtypes of the RGSs (RGS2, RGS4 and RGS7) in developing rat brains by in situ hybridization through postnatal day 2 (P2), P10 and P18 to adult. The most dramatic changes of expression patterns were observed in the discrete neuronal cell layers of the cerebral neocortex (for RGS2 and 4), the hippocampus (for RGS2, 4 and 7), the thalamus (for RGS4) and the cerebellum (for RGS2 and 7). In the neocortex, RGS2 mRNA was enriched in the superficial cortical plate at P2, in contrast to RGS4, which was enriched in more mature neurons of the deeper layer V and VI. In the hippocampus, the neuronal cell layer-specific expression pattern of RGS2 developed from P2 to P18. RGS4 expression was temporarily confined to the CA pyramidal cell layer and not detectable in the dentate gyrus at P10 and P18. Similarly, a high level of expression of RGS7 was observed in the CA area, but not in the dentate gyrus at P2 and P10. In the cerebellum, the maturation of laminar expression patterns for the three RGSs correlated with neuronal maturation and synaptogenesis at P18. The most characteristic temporal pattern among the three RGSs was observed for RGS4 mRNA, which was highly enriched in the thalamocortical regions. The peaks of RGS4 expression were seen in the following regions with distinct onset and duration: the neocortex (from P2 onward), the hippocampus (P10 and P18) and the thalamus (from P18 onward). The divergent temporal and spatial expression of RGS subtypes and their dynamic control in the cortex, the hippocampus and the thalamus suggest that the RGS family could play multiple distinct roles in experience-dependent brain development.
MeSH Terms
- Aging
- Animals
- Animals, Newborn
- Brain
- Cell Differentiation
- Female
- GTP-Binding Proteins
- Gene Expression Regulation, Developmental
- Male
- Neuronal Plasticity
- Neurons
- RGS Proteins
- RNA, Messenger
- Rats
- Rats, Inbred F344
- Rats, Sprague-Dawley
- Sensation
- Synaptic Transmission
A clone of the regulator of G-protein signalling, RGS9, was isolated from a rat striatum-minus-cerebellum-minus-hippocampus subtracted library generated by directional tag polymerase chain reaction subtraction. The full-length cDNA clone encodes a 444 amino acid protein containing an 118 amino acid RGS domain, which corresponds to an evolutionarily conserved domain that is present in all members of the RGS family of proteins. Outside of the homology domain, RGS9 shows more extended similarity to human RGS6 and RGS7, rat RGS12, and the C. elegans protein EGL-10. During embryonic and early postnatal stages of development, two RGS9 transcripts of approximately 1.4 Kb and 1.8 Kb were detected in whole brain. After postnatal day 10, accumulation of the larger transcript increased progressively until adulthood at the expense of the smaller transcript, which was undetectable in the adult. In adult rat brain, the 1.8-Kb RGS9 transcript was detected in the striatum but not in other brain regions or peripheral tissues. In situ hybridization in rat and mouse demonstrates that RGS9 mRNA is expressed predominantly in medium-sized, spiny neurons of the neostriatum and in neurons of the nucleus accumbens and olfactory tubercle. Relatively strong signals were also detected in some hypothalamic nuclei. Its selective expression suggests that RGS9 may play an important role in modulation of the complex signalling pathways of the basal ganglia.
MeSH Terms
- Aging
- Amino Acid Sequence
- Animals
- Base Sequence
- Brain
- Caenorhabditis elegans
- Cloning, Molecular
- Conserved Sequence
- Corpus Striatum
- Evolution, Molecular
- GTP Phosphohydrolases
- GTP-Binding Proteins
- GTPase-Activating Proteins
- Gene Expression Regulation, Developmental
- Gene Library
- Humans
- Mice
- Molecular Sequence Data
- Polymerase Chain Reaction
- Protein Biosynthesis
- Proteins
- RNA, Messenger
- Rats
- Recombinant Proteins
- Sequence Alignment
- Sequence Homology, Amino Acid
- Signal Transduction
- Transcription, Genetic