Polymorphisms in human dopamine D2 receptor gene affect gene expression, splicing, and neuronal activity during working memory

doi:10.1073/pnas.0707106104

Polymorphisms in human dopamine D2 receptor gene affect gene expression, splicing, and neuronal activity during working memory

*Program in Pharmacogenomics, Department of Pharmacology,
^§Department of Psychiatry, Division of Human Genetics, College of Medicine, and College of Pharmacy, and
^‡Division of Biostatistics, College of Public Health, Ohio State University, Columbus, OH 43210; and
^†Group of Psychiatric Neuroscience, Department of Neurology and Psychiatry, University of Bari, 70124 Bari, Italy

Edited by Edward G. Jones, University of California, Davis, CA, and approved October 25, 2007 (received for review July 29, 2007)

Abstract

Subcortical dopamine D2 receptor (DRD2) signaling is implicated in cognitive processes and brain disorders, but the effect of DRD2 variants remains ambiguous. We measured allelic mRNA expression in postmortem human striatum and prefrontal cortex and then performed single nucleotide polymorphism (SNP) scans of the DRD2 locus. A previously uncharacterized promoter SNP (rs12364283) located in a conserved suppressor region was associated with enhanced DRD2 expression, whereas previously studied DRD2 variants failed to affect expression. Moreover, two frequent intronic SNPs (rs2283265 and rs1076560) decreased expression of DRD2 short splice variant (expressed mainly presynaptically) relative to DRD2 long (postsynaptic), a finding reproduced in vitro by using minigene constructs. Being in strong linkage disequilibrium with each other, both intronic SNPs (but not rs12364283) were also associated with greater activity of striatum and prefrontal cortex measured with fMRI during working memory and with reduced performance in working memory and attentional control tasks in healthy humans. Our results identify regulatory DRD2 polymorphisms that modify mRNA expression and splicing and working memory pathways.

Footnotes

^¶To whom correspondence should be addressed at:
Department of Pharmacology, College of Medicine and Public Health, Ohio State University, 333 West 10th Avenue, Columbus, OH 43210-1239.
E-mail: wolfgang.sadee{at}osumc.edu
Author contributions: Y.Z., A.B., and W.S. designed research; Y.Z., L.F., G.B., A.R., R.R., and D.W. performed research; Y.Z., A.B., L.F., G.B., A.R., R.R., M.-L.T.L., T.X., A.P., D.W., and W.S. analyzed data; and Y.Z., A.B., M.-L.T.L., and W.S. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0707106104/DC1.