Gene expression analysis to identify Myc-regulated long noncoding RNAs in B cells with variable Myc levels

Myc is a well known transcription factor with important roles in cell cycle, apoptosis and cellular transformation. Long non-coding (lnc)RNAs have recently emerged as a important class of regulatory RNAs. Here, we show that lncRNAs are an extensive component of the Myc-regulated transcriptional program. Using the P493-6 inducible Myc model we demonstrate that both Myc-induced mRNAs and lncRNAs were significant enriched for Myc binding sites. In contrast to Myc-repressed mRNAs, Myc-repressed lncRNAs were significantly enriched for Myc binding sites. Subcellular localization analysis revealed that Myc-repressed lncRNAs and mRNAs are enriched in the nucleus while Myc-induced lncRNAs and mRNAs are enriched both in the cytoplasm and nucleus. Parallel analysis of differentially expressed lncRNAs and mRNAs identified 105 lncRNA-mRNA pairs that were in close vicinity, indicative for regulation in cis. To support the potential relevance of the Myc-regulated lncRNAs in cellular transformation, we analyzed their expression in primary Myc-high and Myc-low B-cell lymphomas. In total, 54% of the lncRNAs differentially expressed between the lymphoma subsets were identified as Myc-regulated in P493-6 cells. This study is the first to show that lncRNAs are an important factor within the Myc-regulated transcriptional program and indicates a marked difference between Myc-repressed lncRNAs and mRNAs. P493-6: 72h Tet treated (low c-myc levels), t=4h (intermediate c-myc levels), t=24h (high c-myc levels), untreated (steady state c-myc levels) Expression of all known mRNAs and >10 000 lncRNAs was assessed in P493-6 B cells with different c-myc levels