title: The 5' ends of Escherichia coli lac mRNA.
abstract: We identified the predominant 5' ends of an mRNA in Escherichia coli to the exact nucleotides. There are four such ends of lac mRNA in fully induced cells. About 70% of the molecules have the reported major in vitro end, A-A-U-U-G (at +1), which is located 38 nucleotides before the A-U-G translation start. Another 15% start with A-U-U-G at +2, and about 8% start with A-U-U-A-G at -52. A fourth class of molecules begin with either A-G, C-A-G, A-C-A-G, or a weak A-C-A-C-A-G (at +24), observed only once. The origins of this latter set (less than or equal to 10% of the total) are not known, but they could represent "ragged" ends of the mRNA when it is degraded to the beginning of the ribosome-protected region of the message. The A-U-U-A-G molecules are probably initiated from an upstream promoter whose position would coincide with the cAMP-CRP DNA binding site for the major promoter.
authors.forename: V J
authors.initials: VJ
authors.lastname: Cannistraro
authors.forename: D
authors.initials: D
authors.lastname: Kennell
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D007763:Lac Operon; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D012329:RNA, Bacterial; D012333:RNA, Messenger; D014158:Transcription, Genetic
chemical_list: D012329:RNA, Bacterial; D012333:RNA, Messenger