Browsing of DMRs located on first - Alus showed that transcription - factor binding sites are also present upstream of the differentially methylated Alu ( example Figure 5E , bottom track ) . To investigate whether these sites would eventually become accessible under conditions of low DNA methylation at the first - Alu , we examined JunB ChIP - seq data in either resting or activated T - cells ( 49 ) at the interval between the first - and the second - Alu ( schematic Figure   5F ) . Heatmaps showed that in activated T - cells , JunB binding eventually invaded the Alu1 - Alu2 interval at a small number of promoters carrying weak MeDIP signal at the first - Alu ( Figure 5 G , framed region ) . We did however not detect any signal beyond the second Alu element . We next used the same dataset to examine the distribution of NF - B at promoter - proximal Alu elements upon T - cell activation . Unlike JunB , NF - B was reported to use Alu elements as binding platforms ( 51 ) . Yet , we observed only minor accumulation of this transcription factor on first - and second - Alus ( Supplementary Figure S5D ) . In addition , this accumulation did not seem to correlate with promoter activity , as increased NF - B density on Alu elements was observed at the bottom of the heatmap , matching promoters with low H3K4me3 signal ( Supplementary Figure S5D , green arrow ) . This further suggests that Alu elements neighboring promoters do not systematically function as enhancer elements .