MYC Mediates mRNA Cap Methylation of Canonical Wnt/beta-catenin Signaling Transcripts by Recruiting CDK7 and RNA Methyltransferase

We performed an RNA pulldown against a methyl group on the mRNA cap using a fusion protein, GST-eIF4E, highly specific for a m7G-mRNA cap. We performed RNA-seq on both the pulldowns and inputs and normalized our pulldown to input in order to determine which genes MYC targets for mRNA cap methylation above and beyond any affect at the transcriptional level. We found that MYC targets approximately 30% of transcripts for enhanced mRNA cap methylation above 1.2 fold on a global scale following 24 h of MYC induction, specifically transcripts involved in the canonical Wnt/ß-catenin signaling pathway. We used this dataset to validate transcripts targeted by MYC for mRNA cap methylation and to help us determine the mechanism responsible for this phenomenon. Overall design: Examination of MYC-mediated mRNA cap methylation on a global scale by isolating methyl-capped (m7G) mRNA from P493-6 cells with varying MYC levels for further analysis.