Methylation inhibits the interaction of DNA binding proteins with a potential c-abl intron regulatory element

We have identified DNA binding proteins which interact with a sequence found in an intron of the tyrosine kinase coding portion of the murine c-abl gene. Several specific DNA: protein complexes were observed. Those complexes of approximate molecular weights 64 and 66kDa were detected when an Msp I site (CCGG) within the sequence was unmethylated, but were not observed when that site was methylated. Insertion of the intron sequence 5' to the rat somatic cytochrome C promoter and chloramphenicol acetyl transferase (CAT) sequences resulted in at least four-fold stimulation of CAT activity. These data suggest a potential role for the intron sequence in the regulation of gene expression.