Increased Expression of Escherichia coli Polynucleotide Phosphorylase at Low Temperatures Is Linked to a Decrease in the Efficiency of Autocontrol
AUTOR(ES)
Mathy, N.
FONTE
American Society for Microbiology
RESUMO
Polynucleotide phosphorylase (PNPase) synthesis is translationally autocontrolled via an RNase III-dependent mechanism, which results in a tight correlation between protein level and messenger stability. In cells grown at 18°C, the amount of PNPase is twice that found in cells grown at 30°C. To investigate whether this effect was transcriptional or posttranscriptional, the expression of a set of pnp-lacZ transcriptional and translational fusions was analyzed in cells grown at different temperatures. In the absence of PNPase, there was no increase in pnp-lacZ expression, indicating that the increase in pnp expression occurs at a posttranscriptional level. Other experiments clearly show that increased pnp expression at low temperature is only observed under conditions in which the autocontrol mechanism of PNPase is functional. At low temperature, the destabilizing effect of PNPase on its own mRNA is less efficient, leading to a decrease in repression and an increase in the expression level.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=95266Documentos Relacionados
- Long-Term Survival of Campylobacter jejuni at Low Temperatures Is Dependent on Polynucleotide Phosphorylase Activity▿
- The gene coding for polynucleotide phosphorylase in Photorhabdus sp. strain K122 is induced at low temperatures.
- Spermidine Acetyltransferase Is Required To Prevent Spermidine Toxicity at Low Temperatures in Escherichia coli
- Polynucleotide Phosphorylase Has a Role in Growth of Escherichia coli
- The first step in the functional inactivation of the Escherichia coli polynucleotide phosphorylase messenger is a ribonuclease III processing at the 5' end.
