Transcriptional Analysis of the Sfa and Pap Determinants of Uropathogenic Escherichia Coli Strains
The transcriptional and post-transcriptional events occurring in the proximal part of the pap and sfa determinants were quite similar.In both cases there was the generation,by mRNA processing,of a major transcript coding for the major fimbrial subunit.Furthermore,the gene coding for the major subunit together with the genes located down-stream out to the longest gene,coding for the outer membrane translocation protein,were represented also by sfa(B)A-F and papA-H transcripts.
In both operons processing of the mRNA at sites flanking the sequences coding for the outer membrane translocation protein (PapC and SfaF)occurred.The resulting transcripts,which should represent such genes,were presumably quickly degraded.
The three distal genes of the sfa operon were represented by a transcript generated by a cleavage process.The distal part of the pap operon contains more genes than the sfa operon,and it suffered two more cleavages that generated one distal transcript containing the gene papE coding for the major subunit of the fimbria tip.
We suggest that several endoribonucleolytic cleavages occur in the mRNA from fimbrial adhesin operons.Such post-transcriptional mRNA processing events result in differential gene expression of importance to adhesin biogenesis.
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