Intracellular production of hydrogels and synthetic RNA granules by multivalent molecular interactions

• DOI: 10.1038/nmat5006
• Publication Date: 2017-11-06T16:00:48Z
• Authors: Hideki Nakamura; Albert A. Lee; Ali Sobhi Afshar; Shigeki Watanabe; Elmer Rho; Shiva Razavi; Allister Suarez; Yu-Chun Lin; Makoto Tanigawa; Brian Huang; Robert DeRose; Diana Bobb; William Hong; Sandra B. Gabelli; John Goutsias; Takanari Inoue
• Keywords: 0301 basic medicine; 0303 health sciences; 03 medical and health sciences; Polymers; COS Cells; Chlorocebus aethiops; Animals; RNA; Biocompatible Materials; Hydrogels

Some protein components of intracellular non-membrane-bound entities, such as RNA granules, are known to form hydrogels in vitro. The physico-chemical properties and functional role of these intracellular hydrogels are difficult to study, primarily due to technical challenges in probing these materials in situ. Here, we present iPOLYMER, a strategy for a rapid induction of protein-based hydrogels inside living cells that explores the chemically inducible dimerization paradigm. Biochemical and biophysical characterizations aided by computational modelling show that the polymer network formed in the cytosol resembles a physiological hydrogel-like entity that acts as a size-dependent molecular sieve. We functionalize these polymers with RNA-binding motifs that sequester polyadenine-containing nucleotides to synthetically mimic RNA granules. These results show that iPOLYMER can be used to synthetically reconstitute the nucleation of biologically functional entities, including RNA granules in intact cells.