Evidence for antitermination in Escherichia coli RRNA transcription.
AUTOR(ES)
Aksoy, S
RESUMO
The stable RNA operons of Escherichia coli do not exhibit polarity, even though they make an RNA product that is not translated. By contrast, most E. coli operons that specify proteins exhibit polarity if their translation is interrupted. The transcriptional component of this polarity depends on the action of Rho protein on the exposed mRNA, which results in premature transcription termination. Here we examine how a stable RNA operon (rrnG) transcript is protected from the Rho protein-mediated polarity response. We compared transcription from the ara and the rrnG promoters through a 16S DNA segment. In each case, the promoter-16S sequences were joined to a trp-lac fusion, and lacZ mRNA was examined in rho+ and rho-115 strains. We found significant Rho protein-dependent termination of transcripts from the ara promoter but little or no Rho protein effect on transcription from the rrnG promoter. We concluded that the transcript of the 16S ribosomal DNA segment does contain Rho protein-dependent transcription terminators, but there is an antitermination system in the rrnG control region that allows it to transcribe through those terminators.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=215622Documentos Relacionados
- Antitermination mechanisms in rRNA operons of Escherichia coli.
- Evidence for transcription antitermination control of tryptophanase operon expression in Escherichia coli K-12.
- Defective antitermination of rRNA transcription and derepression of rRNA and tRNA synthesis in the nusB5 mutant of Escherichia coli.
- rRNA transcription rate in Escherichia coli.
- Control of rRNA transcription in Escherichia coli.
