title: Methylated, blocked 5 termini in HeLa cell mRNA.
abstract: Poly(A)-containing HeLa cell mRNA prepared from cells labeled with [methyl-(3)H]methionine or [(32)P]phosphate was found to contain a variety of methylated, blocked 5'-terminal structures of two general types: m(7)GpppN(7)-Np and m(7)GpppN(m)-N(m)-Np. In addition, about one-third of the [(3)H]methyl label was present in the N(6)-methyladenosine; this labeled nucleoside was not found in the 3'-terminal one-third of the mRNA chain and thus may also be in the 5' portion of the mRNA.
mesh_terms: D001483:Base Sequence; D002848:Chromatography, DEAE-Cellulose; D006367:HeLa Cells / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D008715:Methionine / Q000378:metabolism; D008745:Methylation; D009841:Oligonucleotides / Q000032:analysis; D010710:Phosphates / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis* / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis* / Q000378:metabolism; D012260:Ribonucleases; D012265:Ribonucleotides / Q000032:analysis
chemical_list: D009841:Oligonucleotides; D010710:Phosphates; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D012265:Ribonucleotides; D008715:Methionine; D012260:Ribonucleases