SsrA genes of streptomycetes and association of proteins to the tmRNA during development and cellular differentiation

Abstract

Transfer-messenger RNA (tmRNA, 10Sa RNA, ssrA) is bacterial RNA having both tRNA and mRNA properties and playing an essential role in recycling of 70S ribosomes that are stalled on defective mRNA. The trans-translational system is thought to play a crucial role in bacterial survival under adverse conditions. Streptomycetes are Gram-positive soil bacteria exposed to various physical and chemical stresses that activate specialized responses such as synthesis of antibiotics and morphological differentiation. Comparative sequence analysis of ssrA genes of streptomycetes revealed the most significant differences in the central parts of tag-reading frames, in the stop codons and in the 15-34 nucleotide sequences following stop codons. A major challenge in understanding the interactions that control the function of tmRNA is the definition of protein interactions. Proteins from various phases of development of Streptomyces aureofaciens associated with tmRNA were analyzed. Using affinity chromatography on tmRNA-Sepharose and photo cross-linking experiments with [(32)P]labeled tmRNA seven proteins, the beta and beta'-subunits of DNA dependent RNA polymerase, polyribonucleotide nucleotidyltransferase (PNPase), ribosomal protein SS1, ATP-binding cassette transporters, elongation factor Tu, and SmpB were identified among the proteins associated with tmRNA of S. aureofaciens. We examined the functional role of ribosomal protein SS1 in a defined in vitro trans-translation system. Our data show that the protein SS1 that structurally differs from S1 of Escherichia coli is required for translation of the tmRNA tag-reading frame.

Francisella tularensis tmRNA system mutants are vulnerable to stress, avirulent in mice, and provide effective immune protection

“…A highly intriguing feature of the tmRNA system is that its function has been adapted to fulfil the specific physiological needs of various bacterial species. Studies of tmRNA in several distinct bacterial species (Withey and Friedman, 1999;Keiler and Shapiro, 2003;Shin and Price, 2007;Abe et al, 2008;Keiler, 2008;Mikulik et al, 2008;Thibonnier et al, 2008;Ujiie et al, 2009;Okan et al, 2010) have yielded new and unique insights into the structure, function and diverse physiological roles played by this system. Our studies of the tmRNA system in F. tularensis demonstrate that this small-genome bacterium has an active trans-translation system that is important for normal growth, resistance to a variety of stress conditions and virulence of the pathogen in a mouse model of tularemia.…”

tmRNA of Streptomyces collinus and Streptomyces griseus during the growth and in the presence of antibiotics

“…, 2005). In experiments with S. aureofaciens, we found that the highest level of SmpB was in the cells from exponential phase of growth and a descending amount in the cells from stationary phase (Mikulík et al. , 2008), which indicates that availability of the SmpB can be involved in regulation of tmRNA stability.…”

“…In experiments with S. aureofaciens, we found that the highest level of SmpB was in the cells from exponential phase of growth and a descending amount in the cells from stationary phase (Mikulík et al, 2008), which indicates that availability of the SmpB can be involved in regulation of tmRNA stability. A previous study demonstrated that antibiotics causing amino acid misreading (kanamycin, streptomycin, hygromycin B, paromomycin and gentamicin) induce read-through of stop codons and enhance the tmRNA mediated protein tagging.…”

“…The most significant differences between ssrA genes of S. aureofaciens, S. collinus and S. griseus are in the central regions of the tag‐encoding parts and in the sequences about 20 nt following termination codons. These differences in the tag‐encoding domains are most probably involved in recognition signals of specific proteolysis system (Mikulík et al. , 2008).…”

Differential transcriptional profile of Corynebacterium pseudotuberculosis in response to abiotic stresses

“…Compared to the synthesis of regulatory proteins, less energy is needed for the synthesis of a small RNA (sRNA) [55]. Among the ncRNAs detected in the genome, riboswitches (elements that control expression in response to various metabolites and can function as sensors or binding sites for a receptor protein that senses a change in the cellular environment) were identified through the analysis of active transcripts.…”