Figure 2.

Model of Pumilio proteins (PUM)-mediated posttranscriptional gene regulation. PUM protein contains RNA-binding domain PUF (in pale blue). PUM protein binds to PBE motif (rectangle in red), located within 3′ untranslated region (3′UTR) of specific mRNA targets (1, 2 or 3), by engaging PUF domain. PUM-binding enables recruitment of different protein cofactors, presented schematically as ovals (in grey, brown, yellow, green, maroon and blue). Depending on the protein complexes that are formed upon PUM-binding, the mRNA target is directed towards repression and/or degradation, specific subcellular localization or stabilization and/or translational activation. The 5′cap structure is presented as the grey half circle; ORF—open reading frame.