Abstract
Cytosolic sulfotransferases (SULTs) catalyze sulfation and play essential roles in detoxification of xenobiotics as well as inactivation of endobiotics. SULT4A1, which was originally isolated as a brain-specific sulfotransferase, is the most highly conserved isoform among SULTs in vertebrates. Here, expression of SULT4A1 was examined neuron enriched and neuron-glia mixed cells derived from mouse embryo brains at day 14 gestation and mixed glia from 2-day-old neonate brains. Western blots showed an increase of SULT4A1 expression as neurons maturated. Reverse-transcription polymerase chain reaction and agarose gel analysis found two different forms (variant and wild type) of SULT4A1 mRNA in neurons; the level of wild type correlated with the protein level of SULT4A1. SULT1E1 was not expressed in mouse brains, neuron-enriched cells, or mixed glia cells. SULT1A1 protein was only detected in adult brains. Immunofluorescence staining of neuron-glia mixed cells confirmed selective expression of SULT4A1 in neurons, including dopaminergic neurons, but not in either astrocytes or microglia. Thus, SULT4A1 is a neuron-specific sulfotransferase and may play a role in neuronal development.