SPECIFIC DEMETHYLATION OF THE CD4 GENE DURING CD4 T-LYMPHOCYTE DIFFERENTIATION

The expression of CD4 during T cell development is a highly regulated process. Numerous regulatory elements have been identified including a promoter, two distinct enhancers and a silencer. Here we report a met hylation site in the first intron of the CD4 gene that is specifically demethylated in cells which have previously, or are currently express ing CD4. In addition, this site becomes progressively demethylated as T lymphocytes differentiate from double-negative to double-positive to CD4 single-positive thymocytes, and finally to CD4 single-positive pe ripheral T lymphocytes. This specific and progressive demethylation su ggests that this site represents another potential control region for the regulation of CD4. (C) 1997 Elsevier Science Ltd.