A freeze-frame view of eukaryotic transcription during elongation and capping of nascent mRNA.
Ribonuclease footprinting of nascent messenger RNA within ternary complexes of vaccinia RNA polymerase revealed an RNA binding site that encompasses an 18-nucleotide RNA segment. The dimensions of the binding site did not change as the polymerase moved along the template. Capping of the 5' end of the RNA was cotranscriptional and was confined to nascent chains 31 nucleotides or greater in length. Purified capping enzyme formed a binary complex with RNA polymerase in solution in the absence of nucleic acid. These findings suggest a mechanism for cotranscriptional establishment of messenger RNA identity in eukaryotes.
Hagler
J
J
Program in Molecular Biology, Sloan-Kettering Institute, New York, NY 10021.
Shuman
S
S
D001483:Base Sequence; D002474:Cell-Free System; D004247:DNA / Q000737:chemistry; D005057:Eukaryotic Cells; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D012315:RNA Caps; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D013698:Templates, Genetic; D013728:Terminator Regions, Genetic; D014157:Transcription Factors / Q000502:physiology; D014158:Transcription, Genetic; D014616:Vaccinia virus
D012315:RNA Caps; D012333:RNA, Messenger; D014157:Transcription Factors; D004247:DNA; D012319:RNA Polymerase II