Tudor-SN and ADAR1 are components of cytoplasmic stress granules

Hyperediting by adenosine deaminases that acts on RNA (ADARs) may result in numerous Adenosine-to-Inosine (A-to-I) substitutions within long dsRNA. However, while countless RNAs may undergo hyperediting, the role for inosine-containing hyperedited dsRNA (IU-dsRNA) in cells is poorly understood. We have previously shown that IU-dsRNA binds specifically to various components of cytoplasmic stress granules, as well as to other proteins such as Tudor Staphylococcal Nuclease (Tudor-SN). Tudor-SN has been implicated in diverse roles in mammalian cells, including transcription, splicing, RNAi, and degradation. Moreover, we have shown that Tudor-SN interacts directly with stress granule proteins. Here we show that Tudor-SN localizes to cytoplasmic stress granules in HeLa cells undergoing arsenite-induced oxidative stress, or following transfection with long dsRNA (poly[IC]), which initiates an interferon cascade. We additionally demonstrate a novel interaction between Tudor-SN and ADAR1. Finally, we show that ADAR1 is also localized to stress granules in HeLa cells following various stresses.