Robust mammalian RNA localization elements are large and multipartite

However, for most localized RNAs, the identities of these elements are unknown. We had previously identified several localization elements that are necessary and sufficient for robust, kinesin-dependent RNA targeting to microtubule plus ends in a variety of cell types.

Yet the characteristics of these elements that are critical for function remained unclear. To address this, we systematically created tens of thousands of mutant localization elements and quantified their ability to regulate subcellular RNA localization in neuronal cells. We found that the minimally active size of these localization elements is large, approximately 200 nt.