Staufen Binds to the 3'-UTR of the Requiem RNA and Regulates Requiem Gene Expression at Translational Level

초록

Requiem is a novel zinc finger protein which was identified as an essential member for apoptosis in myeloid cells. We identified G8 that encodes a part of the 3'-UTR of the requiem gene as a putative globin gene switching factor, showing that transient over-expression of clone G8 in K562 cells induces γ- to β-globin switching. Our observations support the notion that the expression of requiem gene is regulated by 3'-UTR-mediated translational control. Among several putative clones, hStaufen was characterized in this study. We confirmed that hStaufen, as a member of RUBP complex, recognize the core region of the requiem 3'-UTR by North-Western blotting, RNA gel mobility shift, and supershift assays. Thus, consistent with recent findings that the Staufen co-fractionated with ribosomes and associated with both the 40 and 60 S ribosomal subunits, our results strongly suggest that hStaufen plays a critical role in translation repression by interacting with translational machinery.