Figure 3

Gene activations and suppressions mediated by Alu-carrying RNAs. (A) A conceptual interaction network, where any two RNA species that may form a long (280~300 bp) Alu duplex were depicted by mutual inhibition signs. Central to the regulation network are Ant-alus and Sens-alus, which together represent 7.3% of total protein-coding genes. Their RNA levels may affect downstream protein levels. Pol III derived Alus may also form a binding with Ant-alus, enabling a mutual regulation. A few non-coding RNAs (ncRNAs) have also been reported elsewhere to bind with Sens-alus and then trigger STAU1-mediated mRNA decay. (B) The activation restriction model. A set of alu-carrying genes was activated and increased expression level in response to outside stimulation. The elevation of these genes increased the Alu element in the cytosol, which can suppress the activation of other Alu-carrying genes which are associated to other pathways. The suppression will continue until the original signal has subsided. Then a new activation can proceed. (C) Waves of genes are activated coordinately, with different set of genes activated in different time, due to Alu-mediated suppression.