Defects in THO/TREX-2 function cause accumulation of novel cytoplasmic mRNP granules that can be cleared by autophagy

hpr1Δ TT foci are insensitive to cycloheximide, suggesting impaired exchange of resident mRNPs with polysomes. (A) WT and hpr1Δ null strains were transformed with pRP1657 and examined in midlog. WT strain was subject to 30 min of NaN₃ stress (0.5% w/v) followed by 1 h of 100 µg/mL cycloheximide treatment. hpr1Δ strain was examined in midlog and exposed to an identical cycloheximide treatment. Data representative of observations in three biological replicates (separate culture and transformant). Scale bar = 2.5 µM. (B) Quantification of total Pab1 foci levels in WT cells shown in A, normalized to timepoint 0. (C) Quantification of total Pab1 foci levels in hpr1Δ cells shown in A, normalized to timepoint 0.