%0 Journal Article
%T Cap-specific, terminal N6-methylation by a mammalian m6Am methyltransferase
%A Chengqi Yi
%A Dongsheng Bai
%A Hanxiao Sun
%A Kai Li
%A Meiling Zhang
%J Archive of "Cell Research".
%D 2019
%R 10.1038/s41422-018-0117-4
%X Identification of N6,2¡ä-O-dimethyladenosine methyltransferase. a Chemical structure of m6Am, which is adjacent to the m7G mRNA cap. b Cartoon view of the predicted domain structure of PCIF1, with the conserved ¡°NPPF¡± motif in the zoom-in view. A sequence alignment is shown below to highlight the high conservation of the key residues for PCIF1 orthologues. Residue 43¨C77 (blue segment) represents the WW domain, and the red segment denotes the putative catalytic methyltransferase domain. c LC-MS/MS quantification of the m6Am/A ratios of HEK293T polyA£¿+£¿RNA treated with control or PCIF1 siRNA (n£¿=£¿3). d LC-MS/MS quantification of the m6A/A ratios of HEK293T polyA+ RNA treated with control or PCIF1 siRNA (n£¿=£¿3). e Quantification of the m6Am/(Am£¿+£¿m6Am) ratios in RNA probes starting with different cap structure (n£¿=£¿3). f Quantification of the methylation activity of WT and mutant PCIF1 proteins (n£¿=£¿3). g Distribution of enriched m6A/m6Am peak density across mRNA segments of control and PCIF1 knockdown samples using an m6A-seq protocol with random priming. Each segment was normalized according to its average length in Ref-seq annotation. h One representative transcript harboring m6Am and m6A peaks. The m6Am peak at the 5¡ä-terminal is significantly decreased upon PCIF1 knockdown, while the m6A peak at the 3¡ä-UTR stays the same. The grey line denotes ¡°Input¡±, and the red line denotes ¡°IP¡±. i Boxplot of log2fold change of peak score in PCIF1 knockdown and control mRNA. Enriched peaks are classified into three groups: m6Am peak (near TSS and without GGACH motif), m6A peak (not in TSS and with GGACH motif), and the rest (potentially m6Am£¿+£¿m6A). j A proposed model for mammalian mRNA m6Am modification mediated by PCIF1. *P£¿<£¿0.05; **P£¿<£¿0.01; ***P£¿<£¿0.001; ns, not significan
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6318281/