ssl1-1 mutation affects hyperpolyadenylation in mex67-5 mutant cells. (A) Poly(A) tail length was determined by isolating total RNA from each strain that had been grown continuously at 23 °C (-) or shifted to 37 °C for 30 min (+). The resulting RNAs were digested to completion with RNases T1 and A. The remaining oligo(A) and poly(A) fragments were then end labeled with [32P]pCp and RNA ligase and resolved on 9% polyacrylamide-7 M urea-TBE gels Gels were dried and exposed to X-Omat Blue film. (B) Densitometric analysis of the poly(A) tail length. Lanes corresponding to the samples obtained at restrictive temperature (37 °C) were densitometered using the Quantity One program (Bio-Rad).