N1-methyladenosine profiling of long non-coding RNA in colorectal cancer.

N1-methyladenosine (m1A), is a unique methyl group that confers post-transcriptional modification of gene expression, and plays important roles in various human diseases. However, the abundance of this modification and its effects on long non-coding RNAs (lncRNAs) in human colorectal cancer (CRC) remain unclear. In this study, methylated RNA immunoprecipitation sequencing was performed in three pairs of human CRC and nontumorous tissues to identify m1A peaks and its correlation with differential alterations of lncRNA expression in CRC. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment pathway analyses were applied to predict the potential roles of m1A on gene expression. We found that CRC and adjacent tissues had a noticeable difference in m1A distribution. Notably, HGGAGRA and WGGANGA were recognized as the most significantly enriched motifs, respectively. Co-analysis of methylation and RNA sequencing demonstrated downregulated lncRNAs along with m1A modification in CRC. GO and KEGG pathway analyses revealed that the unique distribution of m1A sites in lncRNAs had a significant correlation with CRC signaling pathways. In conclusion, our results delineated the distribution pattern of m1A methylation on lncRNAs, and provided potential roles of this modification in different pathways and tumor progression of CRC.