THE TRANSCRIPTIONAL ENHANCER ELEMENT, DENUMERABLE-B, REGULATES PROMOTER ACTIVITY OF THE HUMAN NEUROTROPIC VIRUS, JCV, IN CELLS DERIVED FROMTHE CNS

Studies on the regulation of the human neurotropic virus (JCV) promote r, have been focused primarily on the 98 bp tandem repeat sequence whi ch confers glial-specificity to viral gene expression. We demonstrate that a distinct regulatory element outside of the 98 bp region, which spans a stretch of 10 nucleotides (nt) (5'-GGGAATTTCC-3') increases tr anscriptional activity of JCV late (JCV(L)) and early (JCV(E)) promote rs in glial cells. Sequence analysis of this motif reveals extensive h omology to the kappaB sequence of HIV-1 (5'-GGGACTTTCC-3'). A DNA frag ment corresponding to the 10 nt sequence of JCV exhibits transcription al activity when placed upstream of the test promoter in glial cells. The induction mediated by this regulatory motif is moderately enhanced in response to phorbol 12-myristate 13-acetate (PMA) in glial cells. Band-shift and UV-crosslinking experiments suggest that glial cells co nstitutively produce proteins that specifically interact with the JCV kappaB, but not the HIV-1 kappaB motif. Treatment of cells with PMA re sults in formation of new complexes that are sensitive to the kappaB s equences derived from the JCV and HIV-1 genomes. These results suggest that the kappaB sequence located in the JCV genome may play a role in transcriptional regulation of JCV gene expression by interacting with inducible and uninducible nuclear proteins from glial cells.