Numerous studies addressing the in vitro RNA-binding properties of different members of this family of proteins suggest that they are sequence-independent RNA-binding proteins that prefer double-stranded RNAs and highly structured single-stranded RNAs. Northwestern analysis with an SPNR-maltose-binding protein fusion showed that it too can bind to a number of different mRNAs in vitro. Despite the apparent nonspecific binding properties of these proteins in vitro, genetic studies suggest that at least some members of this family interact with selected mRNAs in vivo.
It is possible that the subcellular localization of these RNA-binding proteins is what confers their apparent in vivo specificity for RNA targets. For instance, SPNR may only bind to its RNA target if it is associated with microtubules, a requirement that would help guarantee that only proper temporal and spatial mRNA interactions occur. SPNR’s association with microtubules may also link it to other proteins that help confer RNA-binding specificity in vivo. buy antibiotics online
Translational control of the oskar mRNA in Drosophila oocytes may be regulated by the RNA-binding protein Bruno.