Extended Data Fig. 10: Multi-layered nucleoli exhibit functional advantages in pre-rRNA processing over bipartite nucleoli.
From: Pre-rRNA spatial distribution and functional organization of the nucleolus
a. Representative whole-nucleus images of nascent pre-rRNAs (magenta) and zebrafish Fbl (green) in ZF4 cells at indicated chase time points (0–90 min). Scale bars, 5 μm. b. Radial distribution of pre-rRNA intensities (relative to Fbl centre) in zebrafish embryos at indicated time points from Fig. 4d. c. Radial distribution of pre-rRNA intensities (relative to FBL centre) in HeLa cells at indicated time points from Fig. 4e. d. Human TCOF1 overexpression (OE) induces tripartite-like nucleoli in ZF4 cells and accelerates pre-rRNA outflux. Top, workflow of TCOF1 OE and subsequent 5-EU pulse-chase assay in ZF4 cells. Bottom, representative images of nascent pre-rRNAs (firefly), z-Fbl (green), and TCOF1 (magenta) at indicated time points in wild-type (ZF4-WT) and TCOF1-OE ZF4 cells. Scale bars, 2 μm. e. Top, schematic of the induced tripartite-like nucleolar architecture in TCOF1-OE cells with enhanced FC–DFC unit-like segregation. Bottom, time-course of normalized nascent pre-rRNA signal intensity across chase intervals in WT and TCOF1-OE ZF4 cells. Data were obtained from n = 26, 39, 42 and 38 cells in WT; 14, 7, 19 and 7 cells in TCOF1-OE. Data are mean ± s.e.m. b and c, the curves are fitted with Gaussian non-linear regression. n = 15.
