Feedback regulation of rRNA and tRNA synthesis and accumulation of free ribosomes after conditional expression of rRNA genes.
AUTOR(ES)
Gourse, R L
RESUMO
We have constructed a conditional rRNA gene expression system by fusing a plasmid-encoded rrnB operon to the lambda PL promoter/operator. It was thereby possible to study the events that lead to the regulation of chromosomal rRNA and tRNA synthesis after overproduction of rRNA. rRNA induction resulted in a 2-fold increase in 30S and 50S free ribosomal subunits, whereas the polysome fraction was unaffected. Overproduction of rRNA and "free" ribosomes produced a large repression of rRNA and tRNA synthesis from chromosomal genes and a smaller increase in the concentration of guanosine tetraphosphate. These results lend support to the ribosome feedback regulation model: rRNA and tRNA operons are negatively regulated, either directly or through some intermediate, by free, nontranslating ribosomes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=397195Documentos Relacionados
- Level of rRNA, not tRNA, synthesis controls transcription of rRNA and tRNA operons in Escherichia coli.
- Cross Talk between tRNA and rRNA Synthesis in Saccharomyces cerevisiae
- Deletion analysis of the expression of rRNA genes and associated tRNA genes carried by a lambda transducing bacteriophage.
- Defective antitermination of rRNA transcription and derepression of rRNA and tRNA synthesis in the nusB5 mutant of Escherichia coli.
- Accurate transcription of homologous 5S rRNA and tRNA genes and splicing of tRNA in vitro by soluble extracts of Neurospora.
