Adjacent nuclear factor-1 and activator protein binding sites in the enhancer of the neurotropic JC virus. A common characteristic of many brain-specific genes.
JC virus is a neurotropic virus that causes the demyelinating disease progressive multifocal leukoencephalopathy in humans. In order to understand the neurotropic nature of this virus, we examined the binding of nuclear proteins to the viral regulatory region. A close association of nuclear factor-1 (NF-1) and Jun protein binding sites was found. These binding sites were either adjacent or overlapped each other. Depending on the order of binding, there was some interference of binding of the NF-1 protein by Jun even at a non-Jun binding site. This suggests that there may be a direct interaction between these proteins. Examination of the regulatory region of a number of genes expressed in the central and peripheral nervous systems revealed that many of these genes apparently have adjacent NF-1 and activator protein binding sites immediately upstream from the mRNA start site. Since it had been demonstrated that nuclear proteins from brain and non-brain cells could interact with these sites, it is probable that the NF-1- and Jun-related proteins which interact at these sites are involved in the basal activity of these genes. It appears that adjacent binding sites for NF-1 and Jun immediately upstream from the mRNA start site may be a characteristic of many genes expressed in the nervous system.