Fig. 7. enp1 and rio2 ts mutants as well as a GAL1::TSR1 depletion strain are defective in synthesis and nuclear export of 40S subunits. (A) In vivo assay to analyze ribosomal export of 40S and 60S subunits. Ts mutants were shifted for 4 h to 37°C before nuclear accumulation of Rps2p–eGFP (40S subunit reporter) and Rpl25p–eGFP (60S subunit reporter) was determined by fluorescence microscopy. The GAL1::TSR1 depletion stain was shifted from galactose- to glucose-containing medium for 12 h at 30°C. (B) Analysis of ribosomal and polysomal fractions isolated by sucrose density gradient centrifugation from enp1-1 and rio2-1 ts strains, grown at 23°C or shifted for 4 h to 37°C. The UV profiles (OD_254nm) of the sucrose gradient are depicted. (C) Growth properties of RIO2 and rio2-1 strains. Serial dilutions were spotted on YPD plates and incubated either for 3 days at 23°C or 4 days at 30, 33 and 37°C.