ermC specifies an rRNA methyltransferase that confers resistance to erythromycin. The expression of this determinant is induced by the addition of erythromycin. The induction mechanism has been shown to operate posttranscriptionally, and its mechanism has been elucidated. We now show that synthesis of the ermC gene product in Bacillus subtilis is also autoregulated by a mechanism operating on the level of translation. The synthesis of methyltransferase was shown to be gene dosage compensated by Western blot analysis. Several mutants were analyzed that specify altered ermC gene products and are deregulated. Analysis of mutants and of the wild-type strain by Northern blotting demonstrated that autoregulation is posttranscriptional. We suggest a translational repression model in which the ermC methyltransferase binds to its own mRNA, at a region that resembles the methylation target site on 23S rRNA. The overall control of ermC expression is discussed in light of these multiple regulatory mechanisms.
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http://dx.doi.org/10.1128/jb.168.3.1133-1141.1986 | DOI Listing |
The sarcin-ricin loop (SRL) is one of the most conserved segments of ribosomal RNA (rRNA). Translational GTPases (trGTPases), such as EF-G and EF-Tu and IF2, form contacts with the SRL that are critical for GTP hydrolysis and factor function. Previous studies showed that expression of 23S rRNA lacking the SRL confers a dominant lethal phenotype in E.
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Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.
Cyclic diguanosine monophosphate (c-di-GMP) is a ubiquitous bacterial secondary messenger with diverse functions. A previous Escherichia coli proteome microarray identified that c-di-GMP binds to the 23S rRNA methyltransferases RlmI and RlmE. Here we show that c-di-GMP inhibits RlmI activity in rRNA methylation assays, and that it modulates ribosome assembly in the presence of kanamycin.
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Civil and Construction Engineering and Environmental and Ecological Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, Indiana, United States 47907. Electronic address:
This study evaluated microbial fitness under selective pressure of various erythromycin concentrations and the development of resistance genes in Escherichia coli (E. coli) and Enterococcus faecalis (E. faecalis).
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Faculty of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.
Identification and analysis of repetitive elements (motifs) in DNA, RNA, and protein macromolecules is an important step in studying structure and functions of these biopolymers. Functional role of NA-BSE (non-adjacent base-stacking element, a widespread tertiary structure motif in various RNAs) in RNA-RNA interactions at various stages of the ribosome function during translation has been investigated in this work. Motifs of this type have been described to date that are reversibly formed during mRNA decoding, moving of the ribosome subunits relative to each other, and moving mRNA and tRNA along the ribosome during translocation.
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Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeș-Bolyai University, 1 M. Kogalniceanu Street, 400084 Cluj-Napoca, Romania.
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