scholarly journals Intragenic suppressors of temperature-sensitive rne mutations lead to the dissociation of RNase E activity on mRNA and tRNA substrates in Escherichia coli

2008 ◽  
Vol 36 (16) ◽  
pp. 5306-5318 ◽  
Author(s):  
T. Perwez ◽  
D. Hami ◽  
V. F. Maples ◽  
Z. Min ◽  
B.-C. Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Temperature Sensitive ◽  
Rnase E

scholarly journals ISOLATION, GENETIC MAPPING AND SOME CHARACTERIZATION OF A MUTATION IN ESCHERICHIA COLI THAT AFFECTS THE PROCESSING OF RIBONUCLEIC ACID

Genetics ◽  
1978 ◽  
Vol 90 (4) ◽  
pp. 659-671
Author(s):  
David Apirion
Keyword(s):  
Escherichia Coli ◽  
Temperature Sensitivity ◽  
Single Point ◽  
5S Rrna ◽  
23S Rrna ◽  
Single Point Mutation ◽  
Temperature Sensitive ◽  
Rnase E ◽  
Nonpermissive Temperature ◽  
Ribonuclease E

ABSTRACT Temperature-sensitive mutants were isolated from an rnc (RNase III-) strain of Escherichia coli, and their rRNA metabolism was analyzed on 3% polyacrylamide gels. One of these mutants was unable to produce 23S and 5S rRNAs at the nonpermissive temperature. When an rnc  + allele was introduced to this strain, it remained temperature sensitive. At the nonpermissive temperature, this strain could then produce 23S rRNA but was unable to make normal levels of 5S rRNA. In matings and transduction experiments, the defect in rRNA metabolism and temperature sensitivity behaved as a syndrome caused by a single point mutation, which was mapped at min 23.5 on the E. coli chromosome. This mutation probably affects an enzyme, ribonuclease E (RNase E), which introduces a cut in the nascent rRNA transcript between the 23S and the 5S rRNA cistrons. The mutation rne is recessive with respect to temperature sensitivity and the pattern of rRNA. Revertants able to grow at 43° and with normal metabolism of rRNA were isolated; genetic analysis showed that they do not contain the original rne mutation, suggesting that they were true revertants. By combining the rne mutation with an rnc mutation, double rnc rne strains were synthesized, which behaved very similarly to the original rnc strain from which the rne mutation was isolated. Such strains have RNA metabolism that is similar to that of rnc strains at permissive temperatures, but at the nonpermissive temperature they fail to synthesize p23, m23 and 5S rRNAs. Thus, the experiments reported here, together with previous studies, suggest the existence of a new processing ribonuclease activity in Escherichia coli, which is called ribonuclease E.

scholarly journals Mutants of Escherichia coli with Temperature-sensitive Malonyl Coenzyme A-Acyl Carrier Protein Transacylase

1974 ◽  
Vol 249 (23) ◽  
pp. 7468-7475
Author(s):  
Mark E. Harder ◽  
Ruth C. Ladenson ◽  
Steven D. Schimmel ◽  
David F. Silbert
Keyword(s):  
Escherichia Coli ◽  
Coenzyme A ◽  
Acyl Carrier Protein ◽  
Temperature Sensitive ◽  
Carrier Protein

scholarly journals LOCALIZED MUTAGENESIS FOR THE ISOLATION OF TEMPERATURE-SENSITIVE MUTANTS OF ESCHERICHIA COLI AFFECTED IN PROTEIN SYNTHESIS

Genetics ◽  
1979 ◽  
Vol 91 (2) ◽  
pp. 215-227
Author(s):  
W Scott Champney
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Temperature Sensitive ◽  
Chromosomal Locus ◽  
Ribosomal Subunits ◽  
Prolonged Incubation ◽  
Temperature Sensitive Mutants ◽  
Inhibition Of Growth ◽  
Localized Mutagenesis

ABSTRACT Two variations of the method of localized mutagenesis were used to introduce mutations into the 72 min region of the Escherichia coli chromosome. Twenty temperature-sensitive mutants, with linkage to markers in this region, have been examined. Each strain showed an inhibition of growth in liquid medium at 44°, and 19 of the mutants lost viability upon prolonged incubation at this temperature. A reduction in the rate of in vivo RNA and protein synthesis was observed for each mutant at 44°, relative to a control strain. Eleven of the mutants were altered in growth sensitivity or resistance to one or more of three ribosomal antibiotics. The incomplete assembly of ribosomal subunits was detected in nine strains grown at 44°. The characteristics of these mutants suggest that many of them are altered in genes for translational or transcriptional components, consistent with the clustering of these genes at this chromosomal locus.

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