Figures & data
Figure 1 Silencer/repressor vs. insulator activity of B1-X35S. This scheme shows the functional differences between a silencer/repressor and an insulator/boundary element. A silencer can repress transcription of near genes through repressive marks that spread along the chromatin, and such effect is independent on the relative position of the repressor (upper part). Instead, and insulator blocks the activity of enhancers on cis-promoters but only when located between both regulatory elements (lower part). Represive marks are indicated as filled circles. Vertical black bars on B1-X35S stand for a transcriptional barrier blocking enhancer activity. Crossed arrows indicate lack of transcription while the green arrow represents positive gene expression.
Figure 2 AhR and Snai2/Slug-mediated B1-X35S insulation. The figure summarizes the differences in B1-X35S-dependent insulation under basal and AhR + Snai2/Slug overexpression conditions.
Figure 3 Retrotransposons as Genomic Traffic Lights. The diagram shows some hypothetical transcriptional outputs for three adjacent genes that have several B1 SINE elements located between them. The generation of specific loci models will be needed to study the dynamics of insulatory networks. B1 elements are colored in red or green to indicate inhibition or activation of gene transcription, respectively.
