title: Changes in the half-life of ribosomal protein messenger RNA caused by translational repression.
abstract: The half-life of ribosomal protein operon L11 mRNA in vivo was measured during exponential growth by following the kinetics of incorporation of radioactive precursors into L11 mRNA transcribed from multi-copy plasmids. The degree of translational feedback regulation by L1, the L11 operon-specific translational repressor protein, was changed by altering the site on the "L11 mRNA" where L1 interacts. The half-life of the overproduced L11 mRNA increased by about fivefold when translational repression was abolished, while the half-life of mRNA from the spc ribosomal protein operon, which is not translationally regulated by L1, stayed constant. Furthermore, the half-life of L11 operon mRNA carrying an additional mutation in the ribosome binding site that abolishes translation remains short. This indicates that the change in half-life observed during increased gene dosage is due to translational repression by L1 and is probably a consequence of L1 blocking translation of L11 mRNA and not due to some nucleolytic activity mediated by L1.
mesh_terms: D001483:Base Sequence; D004926:Escherichia coli / Q000378:metabolism; D006207:Half-Life; D008433:Mathematics; D009154:Mutation; D009690:Nucleic Acid Conformation; D010957:Plasmids; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics*; D012269:Ribosomal Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D012329:RNA, Bacterial; D012333:RNA, Messenger; D012097:Repressor Proteins; D012269:Ribosomal Proteins; D014157:Transcription Factors