title: Evidence for endonucleolytic cleavage at the 5'-proximal segment of the trp messenger RNA in Escherichia coli.
abstract: The 5'-proximal trp leader RNA segment (about 5S) decays at 2 to 3 times slower rates than the distal trp mRNA sequence. This has been demonstrated by employing the deletion mutants which lack a large portion of the structural genes but retain the promoter-proximal region of the trp operon. Relative stability of the leader RNA is not merely due to the presence of an untranslatable region in the segment; the internal untranslatable segment of trp mRNA downstream from the nonsense alteration site of a double mutant trpAD28.trpE9758 decays as fast as the normal trp mRNA sequence. These results suggest that the trp mRNA is endonucleolytically cleaved to yield the small 5'-proximal leader RNA segment before the distal mRNA decays and that the leader RNA sequence is not subject to usual mode of mRNA decay in the 5' to 3' direction.
mesh_terms: D004279:DNA, Viral / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009693:Nucleic Acid Hybridization; D009876:Operon; D012329:RNA, Bacterial / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D004279:DNA, Viral; D012329:RNA, Bacterial; D012333:RNA, Messenger