Figure 4.

Analysis of Polysome Build Up on Newly Transcribed mRNAs

U2OS cells expressing scFv-GFP, PP7-2xmCherry-CAAX, and the translation reporter (SunTag_24x-Kif18b-PP7_24x).

(A) Images from a time-lapse movie of newly transcribed mRNAs undergoing the first rounds of translation.

(B) Quantification of the fluorescence intensity increase, aligned at the first time point at which scFv-GFP signal was detected (n = 30 individual mRNAs [pink lines], and average [black line] is shown).

(C) Quantification of the time between mRNA appearance and the first detection of translation by scFv-GFP fluorescence.

(D) Comparison of scFv-GFP fluorescence buildup on either new transcripts (red line) or on re-initiating mRNAs (black line). Data are re-plotted from Figures 3D and 4B. Scale bar, 2 μm.

See also Movie S6.