The half-life of mRNA in Saccharomyces cerevisiae.

The decay kinetics of mRNA was studied in a yeast temperature-sensitive mutant, ts136, which is defective in cytoplasmic RNA production at 37 degree C. The disappearance of the synthetic capacity of mRNA was determined by withdrawing equal volumes of ts136 cell culture and pulse-labelling with [35S]methionine at various time intervals after the shift to 37 degrees C from 23 degrees C. The synthesized proteins were separated on a two-dimensional gel electrophoretic system and then quantitatively analyzed for theri incorporated radioactivities by scintillation counting. Our results show that yeast mRNAs have divergent functional half-lives ranging from 4.5 to 41 min, with an average value of 22 min. Each mRNA exhibits a simple exponential decay with its own characteristic dacay pattern. Of the approximately 500 major polypeptides made by yeast cells, which are detectable on autoradiograms of the gels, 80 were arbitrarily selected and the mRNAs coding for those polypeptides were examined for their decay kinetics.