Monitoring mRNA decapping activity

mRNA decapping is a common step shared between two important mRNA decay pat hways in yeast, Saccharomyces cerevisiae. To investigate how mRNAs are deca pped, we have developed an assay that can be easily used to measure the dec apping activity. This assay has been used to isolate yeast strains with alt ered decapping activities. The results demonstrated that decreased decappin g activity in vitro corresponds well with the decapping-deficient phenotype in vivo. This assay has been applied to the purified yeast decapping enzym e Dcp1 protein as well as crude yeast extracts and Xenopus oocyte extracts. (C) 1999 Academic Press.