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bioRxiv · 10.1101/2020.11.02.366021

Paraspeckles are constructed as block copolymer micelles through microphase separation

Yamazaki, T.·Yamamoto, T.·Yoshino, H.·Souquere, S.·Nakagawa, S.·Pierron, G.·Hirose, T.
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Abstract

Paraspeckles are constructed by NEAT1_2 architectural long noncoding RNAs and possess characteristic cylindrical shapes with highly ordered internal organization, distinct from typical liquid-liquid phase-separated condensates. We experimentally and theoretically investigated how the shape and organization of paraspeckles are determined. We identified the NEAT1_2 RNA domains responsible for shell localization of the NEAT1_2 ends, which determine the characteristic internal organization. We then applied a theoretical framework using soft matter physics to understand the principles that determine the NEAT1_2 organization, shape, number, and size of paraspeckles. By treating paraspeckles as amphipathic block copolymer micelles, we could explain and predict the experimentally observed behaviors of paraspeckles upon NEAT1_2 domain deletions or transcriptional modulation. Thus, we propose that paraspeckles are block copolymer micelles assembled through microphase separation. This work provides an experimentally-based theoretical framework for the concept that ribonucleoprotein complexes (RNPs) can act as block copolymers to form RNA-scaffolding microphase-separated condensates in cells.

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Yamazaki, T., Yamamoto, T., Yoshino, H., Souquere, S., Nakagawa, S., Pierron, G., Hirose, T.. 2020-11-03. Paraspeckles are constructed as block copolymer micelles through microphase separation. https://doi.org/10.1101/2020.11.02.366021

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