Figure 1.

Transcription of rDNA is repressed apparently earlier than that of RP genes in response to a secretory defect. Wild-type cells (W303a) were grown to early log phase in SC–Met medium at 30°C and treated with tunicamycin (2.5 µg/ml). Each culture at the indicated times was taken for (A) pulse-chase analysis with [methyl-³H] methionine or (B) northern analysis. (C) Closed circle, incorporation of [³H] into RNA [as in (A)]; square, open circle and triangle, levels of mRNA for RPL28, RPL7 and RPL3, respectively [as in (B)]. Nomenclature of RP genes follows Mager et al. (18).