Fig. 1: RNA-induced LLPS of the nucleocapsid protein of SARS-CoV-2.
From: Nucleocapsid protein of SARS-CoV-2 phase separates into RNA-rich polymerase-containing condensates
a Organization of NSARS-CoV-2 into two globular domains (RNA-binding domain and C-terminal dimerization domain) surrounded by long intrinsically disordered regions (IDR)4,5. The serine/arginine (SR)-rich region is conserved in coronaviruses. b Influence of RNA and protein concentration on NSARS-CoV-2/polyU-LLPS in 20 mM NaPi, pH 7.5, monitored by solution turbidity at 350 nm. Average values from three independent measurements are shown. The dashed line marks NSARS-CoV-2/polyU-concentrations at which charge neutralization occurs, assuming a charge of −1 per phosphate group. c Fluorescence and DIC microscopy of spherical droplets of 50 µM NSARS-CoV-2 and 1 µM polyU in 20 mM NaPi, pH 7.5. Fluorescently labeled RNA (green) partitioned into the droplets. Scale bar, 20 µm. Micrographs are representative of three independent biological replicates. d Increase in NSARS-CoV-2- and RNA-concentration inside of NSARS-CoV-2/polyU droplets in 20 mM NaPi, pH 7.5. Scale bars 3 µm. Micrographs are representative of three independent biological replicates. e Time-dependent change in diffusion of NSARS-CoV-2 inside polyU-induced droplets observed by FRAP. FRAP of freshly prepared droplets is shown in green, and after incubation for one hour in blue. Error bars represent the standard deviation for averaged six curves for each time point. Representative micrographs of a fresh droplet (top) and after incubation for one hour (bottom) before bleaching, after bleaching, and at the end of recovery are displayed to the right. Scale bars 10 µm.
