Deletion analysis of the c-Ha-ras oncogene promoter.

Using transient assays of chloramphenicol acetyltransferase expression in CV-1 cells, we have localized the human c-Ha-ras oncogene promoter to a 550 bp fragment located about 1 kb upstream from the ras coding sequence. Deletion analysis has revealed that a 100 nucleotide region 200 base pairs upstream of the putative initiation sites for transcription is essential for high levels of expression. Within this sequence lie two Spl binding sites and a consensus CCAAT box.