RGS9
Regulator of G-protein signaling 9 (RGS9)
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Regulators of G protein signaling (RGS) proteins are GTPase-activating proteins which act as modulators of G-protein-coupled receptors. RGS9 has two alternative splicing variants. RGS9-1 is expressed in the retina. RGS9-2 is expressed in the brain, especially abundant in the striatum. It is believed to be an essential regulatory component of dopamine and opioid signaling. In this study, we compared the expression of RGS9 proteins in the nervous system of different age groups of rats employing immunocytochemistry. In both 3-week- and 1-year-old rats, RGS9 is expressed abundantly in caudate-putamen, nucleus accumbens, and olfactory tubercle. It is also expressed abundantly in the ventral horn of the spinal cord and the dorsal root ganglion (DRG) cells. Quantitative analysis showed that the intensities of RGS9 expression in 1-year-old rats are higher than those in the 3-week-old rats in caudate-putamen, nucleus accumbens, olfactory tubercle, periaqueductal gray, and gray matter of the spinal cord. In contrast, in thalamic nuclei and locus coeruleus, the intensities of RGS9 immunostaining in 3-week-old rats are higher than in 1-year-old rats. In DRG cells, there is no significant difference between the two age groups. These data suggest that RGS9 is differentially expressed with age. Such differential expression may play an important role in neuronal differentiation and development as well as in neuronal function, such as dopamine and opioid signaling.
MeSH Terms
- Afferent Pathways
- Age Factors
- Aging
- Animals
- Brain
- Ganglia, Spinal
- Immunohistochemistry
- Male
- Nervous System
- Neurons, Afferent
- Nociceptors
- Pain
- RGS Proteins
- Rats
- Rats, Sprague-Dawley
- Spinal Cord
- Synaptic Transmission
- Up-Regulation
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