The proposed model is as follows
Two cis-elements are located in the 3′UTR of CDK6 mRNA; one is the HNRNPA2B1 binding site, and the other is the miR-506 binding site. The sequences of these two elements are complements of each other and form a stem structure that prevents miR-506 from recruiting the RISC to the 3′ UTR of CDK6 mRNA (the OFF status).Upon cytoplasmic HNRNPA2B1 binding, the stem structure is denatured, which releases the miR-506 cis-element, leading to the recruitment of the miR-506-RISC complex for specific gene silencing (the ON status). These results indicate that a cis-element, the HNRNPA2B1 binding site, in the 3′ UTR of CDK6 mRNA serves as a conserved RNA switch.