Biomaterial Database

PNPase modulates RNase II expression in Escherichia coli: implications for mRNA decay and cell metabolism. 1996

R Zilhão, and F Cairrão, and P Régnier, and C M Arraiano

Instituto de Technologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.

PNPase and RNase II are the key regulatory exonucleases controlling mRNA decay in Escherichia coli. The rnb transcripts were found to proceed through the terminator and PNPase was found to be involved in the 3' to 5' degradation of rnb mRNA. Analysis of these longer 3' termini revealed that they are located in UA-rich regions. Comparison of single and double mutants suggested that PNPase and RNase II could have different roles in the degradation of these unstructured regions. We have shown that RNase II levels can vary over a fivefold range in haploid cells and that its expression depends on PNPase levels. PNPase-deficient strains were found to have a 2-2.5-fold increase in RNase II activity, while PNPase-overproducing strains reduced the rnb message and RNase II levels. Conversely, the amount of PNPase in the rnb deletion strain was approximately twofold higher than that in the wild-type strain. These observations suggest that the two main exonucleases are inter-regulated through a fine tuning mechanism. We discuss the implications of these results with regard to mRNA degradation and cell metabolism.

UI	MeSH Term	Description	Entries
D007763	Lac Operon	The genetic unit consisting of three structural genes, an operator and a regulatory gene. The regulatory gene controls the synthesis of the three structural genes: BETA-GALACTOSIDASE and beta-galactoside permease (involved with the metabolism of lactose), and beta-thiogalactoside acetyltransferase.	Lac Gene,LacZ Genes,Lactose Operon,Gene, Lac,Gene, LacZ,Genes, Lac,Genes, LacZ,Lac Genes,Lac Operons,LacZ Gene,Lactose Operons,Operon, Lac,Operon, Lactose,Operons, Lac,Operons, Lactose
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009876	Operon	In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.	Operons
D011117	Polyribonucleotide Nucleotidyltransferase	An enzyme of the transferase class that catalyzes the reaction RNA(n+1) and orthophosphate to yield RNA(n) and a nucleoside diphosphate, or the reverse reaction. ADP, IDP, GDP, UDP, and CDP can act as donors in the latter case. (From Dorland, 27th ed) EC 2.7.7.8.	Polynucleotide Phosphorylase,Nucleotidyltransferase, Polyribonucleotide,Phosphorylase, Polynucleotide
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005095	Exoribonucleases	A family of enzymes that catalyze the exonucleolytic cleavage of RNA. It includes EC 3.1.13.-, EC 3.1.14.-, EC 3.1.15.-, and EC 3.1.16.-. EC 3.1.-	Exoribonuclease
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA