A predicted RNA-binding domain found in insect Oskar and vertebrate TDRD5/TDRD7 proteins that nucleate or organize structurally related ribonucleoprotein (RNP) complexes, the polar granule and nuage, is poorly understood [1][2]. The domain adopts the ...
A predicted RNA-binding domain found in insect Oskar and vertebrate TDRD5/TDRD7 proteins that nucleate or organize structurally related ribonucleoprotein (RNP) complexes, the polar granule and nuage, is poorly understood [1][2]. The domain adopts the winged helix-turn- helix fold and bind RNA with a potential specificity for dsRNA [1].In eukaryotes this domain is often combined in the same polypeptide with protein-protein- or lipid- interaction domains that might play a role in anchoring these proteins to specific cytoskeletal structures. Thus, proteins with this domain might have a key role in the recognition and localization of dsRNA, including miRNAs, rasiRNAs and piRNAs hybridized to their targets. In other cases, this domain is fused to ubiquitin-binding, E3 ligase and ubiquitin-like domains indicating a previously under-appreciated role for ubiquitination in regulating the assembly and stability of nuage-like RNP complexes. Both bacteria and eukaryotes encode a conserved family of proteins that combines this predicted RNA-binding domain with a previously uncharacterized RNase domain belonging to the superfamily that includes the 5'->3' nucleases, PIN and NYN domains [1].
