Figure 3.

FMR1 RNA induced protein sequestration. The expanded CGG-repeat region in the FMR1 free mRNA can form higher-order structures that can sequester proteins which results in a deficiency within the cell from those proteins. The CGG-repeat region is directly bound by repeat binding proteins such as heterogeneous nuclear ribonucleoproteins A2/B1 (hnRNP A2/B1), DiGeorge syndrome critical region 8 (DGCR8) protein, and Pur-alpha ((Purα) protein. The CGG-repeat region can also indirectly sequester other proteins through the interaction with the directly bound proteins. Proteins that can be indirectly sequestered include Drosha and heterochromatin protein 1 (HP1). (Adapted from Hagerman and Hagerman 2016 and Glineburg et al. 2018) [12,127].