(A) Ded1-mCherry labeled SGs were imaged after addition of 50 μg/ml
cycloheximide (CHX). The ATP-deficient variants do not alter ATP and RNA-binding
(Extended Data Fig. 3b,c) (B)
Quantification of the percentage of SGs per cell normalized to t = 0 min; mean
(solid line) and SEM (shaded area), n=3 biological replicates, at least 150
cells per replicate and strain. (C) A549 cells expressing WT or E179A mutant
UAP56 were infected with influenza virus. After 6h, viral M mRNA was detected by
smFISH and SON by immunofluorescene. Insets: enlargements of the marked white
squares. Data are representative of three independent experiments. (D)
Quantification of nuclear speckle volume (885 speckles per condition). (E)
Quantification of relative M mRNA intensity at nuclear speckles (32 WT cells /
938 speckles and 34 E179A cells / 885 speckles). Mean and SD; two-sided t-test,
*** p = 6.4*10-9. (F) Sub2 depletion leads to accumulation of a
PP7CP-yEGFP labeled reporter mRNA in nuclear foci. Scale bar 5 μm. (G)
Quantification of (F). Mean and SEM of 5 biological replicates with n>78 cells
per time point. (H) Quantification of nuclear focus intensity, 5 (Sub2 degron)
or 6 (WT) biological replicates; at least 13 / 33 cells (60 min WT / degron) or
14 / 60 (90 min WT / degron) cells per replicate. Mean and SEM; unpaired
two-tailed t-test with *** p = 0.0002 and **** p = <0.0001. Dots
represent the mean of individual replicates.