Global analysis of mRNA decay by PLPs. (A) Experimental design for analysis of mRNA decay by PLPs. (B) BioAnalyzer pseudo gel showing degradation of 28 and 18S cytoplasmic rRNAs during PLP aging between 1 and 2 days after purification (see “Methods”). (C) Quantification of 28S (blue diamonds) and 18S (gray diamonds) degradation in (B) compared with quantitative reverse transcription polymerase chain reaction of mitochondrial (mito) 16S rRNA (black diamonds). (D) M-A plot showing changes in transcript abundance between 4 and 6 hours and 1 and 2 hours in PLPs. Histone category includes replication-type nonpolyadenylated mRNAs and replication-independent polyadenylated histone mRNAs. (E,F) Plots of average RNA abundance for gene groups over a 0- to 6-hour time course. FLUC, firefly luciferase; M-A, ratio-average; RP, ribosomal protein.