Reactivation assay to identify direct targets of the nonsense-mediated mRNA decay pathway in Drosophila

Transcriptome analysis provides a snapshot of cellular gene expression and is used to determine how cells and organisms respond to genetic or environmental changes. Identifying the transcripts whose expression levels are regulated directly by the manipulation being examined from those whose expression changes as a secondary cause from the primary changes requires additional analyses. Here we present a technique used to distinguish direct targets of the nonsense-mediated mRNA decay (NMD) pathway in Drosophila from secondary gene expression effects caused by loss of this pathway. This technique uses pulsed reexpression of an essential NMD gene in Drosophila lacking this NMD factor, followed by analysis of the transcriptome over time. In this way, RNAs with a rapid reduction in expression upon reactivation of NMD activity, corresponding to primary NMD targets, can be identified. This technique could potentially be modified to identify direct targets of other mRNA decay mechanisms in Drosophila or other organisms.