Advances in drug metabolism and pharmacogenetics research in Australia.
Sulfotransferase 4A1 (SULT4A1) is a novel cytosolic sulfotransferase that is primarily expressed in the brain. To date, no significant enzyme activity or biological function for the protein has been identified, although it is highly conserved between species. Mutations in the SULT4A1 gene have been linked to schizophrenia susceptibility, and recently, its stability was shown to be regulated by Pin1, a peptidyl-prolyl cis-trans isomerase implicated in several neurodegenerative diseases. In this study, we investigated the transcriptional regulation of mouse Sult4a1. Using a series of promoter deletion constructs, we identified three cAMP-responsive elements (CREs) that were required for maximal promoter activity. The CREs are located within 100 base pairs of the major transcription start site and are also present in the same region of the human SULT4A1 promoter. Electrophoretic mobility shift assays (EMSAs) identified two specific complexes that formed on each of the CREs. One complex contained cAMP response element-binding protein (CREB), and the other contained activating transcription factor-2 (ATF-2) and c-Jun. Overexpression of CREB or ATF-2 increased not only reporter promoter activity but also endogenous Sult4a1 mRNA levels in Neuro2a cells. Moreover, [d-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin (DAMGO) treatment increased both reporter promoter activity and Sult4a1 levels in mu-opioid receptor expressing Neuro2a/mu-opioid receptor cells, and EMSAs showed this to be due to increased binding of CREB and ATF-2 to the Sult4a1 promoter. We also show that DAMGO treatment increases Sult4a1 mRNA and protein levels in primary mouse neurons. These results suggest that Sult4a1 is a target gene for the mu-opioid receptor signaling pathway and other pathways involving activation of CREB and ATF-2.