title: Processed mRNA with differential stability in the regulation of E. coli pilin gene expression.
abstract: E. coli expressing the papA-I genes produce pili that mediate specific adhesion to mammalian cells. We show that the major pilus subunit gene, papA, is part of a polycistronic transcriptional unit subject to specific posttranscriptional processing. A primary transcript also encoding the papB regulatory gene product is endonucleolytically cleaved, resulting in the rapid decay of the papB-encoding 5' half of the mRNA, whereas the papA-encoding 3' half remains as a quite stable transcript. Processing and differential mRNA stability thereby result in accumulation of mRNAs encoding only the major pilus subunit. A sequence immediately downstream of the papA coding region may serve as a stability determinant for the papA transcript and concomitantly attenuate read-through transcription into the minor pilus subunit gene papH. This suggests that differential expression of genes within an operon may include endo- and exonucleolytic processing of the mRNA.
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D036781:Fimbriae Proteins; D005786:Gene Expression Regulation; D005796:Genes; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D036781:Fimbriae Proteins