A repetitive sequence element 3' of the human c-Ha-ras1 gene has enhancer activity.

Efficient expression of the human c-Ha-ras1 gene requires sequences 3' of those specifying the polyadenylation of its transcripts. These sequences can stimulate the expression of heterologous genes in a manner largely independent of position and orientation, arguing that they possess a transcriptional enhancing activity that regulates the c-Ha-ras1 promoter. As this element is associated with a repetitive domain that is highly polymorphic, it is possible that the activity of this enhancer is variable within the human population.