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Developmental regulation of phosphoprotein gene expression in the caudate-putamen of rat: an in situ hybridization
E L Gustafson1, M E Ehrlich, P Trivedi
1Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, NY 10021.
Abstract:
The regional and cellular ontogeny of the mRNA encoding the dopamine- and cAMP-regulated phosphoprotein, DARPP-32, has been studied in rat striatum by quantitative in situ hybridization histochemistry. The mRNA for DARPP-32 exhibited a characteristic developmental profile. The hybridization signal was first visible on the day of birth, at which time DARPP-32 mRNA was concentrated in patches in the caudate-putamen. By the end of the first postnatal week, the majority of neurons in the caudate-putamen expressed the DARPP-32 message. Levels of mRNA per cell increased markedly during the second postnatal week, and peaked around the beginning of the third week. The adult level of DARPP-32 mRNA was lower than that observed at the apex of mRNA expression, on a per cell basis, while the proportion of neurons expressing detectable levels of message remained relatively constant. In the nucleus accumbens and olfactory tubercle, DARPP-32 mRNA development lagged somewhat behind that observed in the caudate-putamen, but was similar in other respects. A non-quantitative study employing an oligonucleotide probe complementary to the mRNA encoding another cAMP-regulated phosphoprotein, ARPP-21, revealed a similar developmental sequence to DARPP-32. The present results suggest that for DARPP-32 mRNA, genetic and, possibly, environmental factors play a role in determining the developmental patterns observed.
Insights
The study tracked dopamine- and cAMP-regulated phosphoprotein (DARPP-32) mRNA development in rat brains. DARPP-32 mRNA levels peaked in the third week, with adult levels lower per cell but widespread expression.
Area of Science:
- Neuroscience
- Molecular Biology
- Developmental Biology
Background:
- Dopamine- and cAMP-regulated phosphoprotein (DARPP-32) is crucial in neuronal signaling.
- Understanding DARPP-32 mRNA ontogeny provides insights into striatal development and function.
Purpose of the Study:
- To investigate the regional and cellular developmental patterns of DARPP-32 mRNA in the rat striatum.
- To compare the developmental trajectory of DARPP-32 mRNA with another cAMP-regulated phosphoprotein, ARPP-21.
Main Methods:
- Quantitative in situ hybridization histochemistry was used to analyze DARPP-32 mRNA distribution and levels.
- Oligonucleotide probes were employed to study ARPP-21 mRNA in a non-quantitative manner.
Main Results:
- DARPP-32 mRNA was detectable at birth, initially in patches within the caudate-putamen.
- Widespread neuronal expression in the caudate-putamen was observed by the first postnatal week, with peak levels around the third week.
- DARPP-32 mRNA development in the nucleus accumbens and olfactory tubercle showed a slight delay compared to the caudate-putamen.
- ARPP-21 mRNA exhibited a similar developmental sequence to DARPP-32.
Conclusions:
- DARPP-32 mRNA expression follows a distinct developmental profile in the rat striatum.
- The developmental patterns of DARPP-32 mRNA suggest the involvement of both genetic and potential environmental factors.
- The findings contribute to understanding the molecular mechanisms underlying striatal maturation.