The 23S-5S spacer of two rRNA loci of Streptococcus salivarius subsp thermophilus includes a promoter

Guédon, Gérard; Pébay, Mireille; Colmin, C; Simonet, Jean-Marc; Decaris, Bernard

doi:10.1016/0300-9084(92)90159-c

Cited by 6 publications

(7 citation statements)

References 20 publications

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“…Each of the six fragments revealed by the I41 probe was hybridized with either the 044 or the TG20 oligonucleotides. Similar results were obtained by hybridizing the two tRNA probes on HindIII digests (23). TG20 hybridized with the four fragments bearing rmB, rnC, rrnD, and rmF loci, and 044 hybridized with the other two fragments bearing mrmA and rrnE loci.…”

Section: Sf3supporting

confidence: 72%

“…Sequence determination of the 5' extremity of the 5S gene and the adjacent downstream region in 144 (n-nE locus) showed the presence of a single tRNA gene, tRNA In. This tRNA gene was found to be immediately followed by a transcription terminator, suggesting that this single tRNA gene was associated with the rrnE locus (23). A similar association has also been described for an rRNA operon in Acholeplasma laidlawii (56).…”

Section: Sf3supporting

confidence: 69%

“…Hybridization of the TG20 oligonucleotide with the four restriction fragments (corresponding to the mnB, nnC, rmD, and rnmF loci) in digests obtained with high-and low-frequency cutting enzymes indicated that each of the four tRNA genes was located downstream from a rn locus. For one of them, comparison of the P20 sequence (from which TG20 was derived) with the ribosomal sequences indicated that the tRNAVal gene was immediately located downstream from the 5S gene (23). For the other three nn loci, we did not know whether the tRNAVal gene was associated with the rm loci or not.…”

Section: Sf3mentioning

confidence: 90%

“…The 044 oligonucleotide, which overlaps the 3' end of the 5S rRNA gene, the 5S-tRNAA" spacer, and two nucleotides of the tRNAA~gene (23), was used as a probe to identify fragments containing the tRNA In gene associated with rm loci. The TG20 oligonucleotide containing the anticodon of a tRNAVal gene (23,53) was then used as a probe to identify all fragments bearing tRNAVal genes. Hybridization results obtained with 044 and TG20 on SmaI and SmaI-BssHII digests are summarized in Table 5.…”

Section: Sf3mentioning

confidence: 99%

“…To date, basic methods of gene transfer by transformation, transduction, or conjugative mobilization have been reported (34). Several genes have been cloned and analyzed, including genes involved in glucide metabolism (lacZ, lacS, galE, galM, and ldh [5,25,43,44,51]) and DNA recombination (recA [15]), ribosomal sequences (4,23,38), and the aspartate racemase gene (62). A marked restriction polymorphism has been detected between different strains of this species by analysis of hybridization patterns obtained with a species-specific probe (13) and with probes by genes coding for rRNA (38).…”

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confidence: 99%

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Physical and genetic map of Streptococcus thermophilus A054

Roussel¹,

Pébay²,

Guédon³

et al. 1994

J Bacteriol

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The three restriction endonucleases Sfil, BssHl, and SmaI were found to generate fragments with suitable size distributions for mapping the genome of Streptococcus thermophilus A054. A total of 5, 8, and 24 fragments were produced with SfiI, BssHI, and SmaI, respectively. An average genome size of 1,824 kb was determined by summing the total fragment sizes obtained by digestions with these three enzymes. Partial and multiple digestions of genomic DNA in conjunction with Southern hybridization were used to map SfI, BssHII, and SmaI fragments. All restriction fragments were arranged in a unique circular chromosome. Southern hybridization analysis with specific probes allowed 23 genetic markers to be located on the restriction map. Among them, six rrn loci were precisely located. The area of the chromosome containing the ribosomal operons was further detailed by mapping some of the ApaI and SgrAI sites. Comparison of macrorestriction patterns from three clones derived from strain A054 revealed two variable regions in the chromosome. One was associated with the tandem rinD and rnnE loci, and the other was mapped in the region of the lactose operon.Streptococcus thermophilus is an economically important lactic acid bacterium used in the manufacture of yoghurt and some hard cheeses. It is a gram-positive, facultative anaerobic microorganism that is exclusively isolated from milk and fermented dairy products. Despite its importance in the dairy industry, genetic studies of S. thermophilus have been limited until recently. To date, basic methods of gene transfer by transformation, transduction, or conjugative mobilization have been reported (34). Several genes have been cloned and analyzed, including genes involved in glucide metabolism (lacZ, lacS, galE, galM, and ldh [5,25,43,44,51]) and DNA recombination (recA [15]), ribosomal sequences (4, 23, 38), and the aspartate racemase gene (62). A marked restriction polymorphism has been detected between different strains of this species by analysis of hybridization patterns obtained with a species-specific probe (13) and with probes by genes coding for rRNA (38). Despite the availability of gene transfer systems and cloned genes, the structure and organization of the S. thermophilus genome are not well defined.Pulsed-field gel electrophoresis (PFGE) (9, 52) has proved to be an efficient method for genome size estimation and construction of chromosomal maps, as well as being a useful tool for the characterization of bacterial species. Preliminary results from PFGE have indicated a genome size of 1.75 Mb for strain STi of S. thermophilus (31) and allowed restriction polymorphism within S. thermophilus to be observed (48).In this study, we used PFGE to estimate the size of the chromosome of S. thermophilus A054 and to construct a physical map by using the restriction enzymes SMaI, Sfil, BssHII, ApaI, and SgrAI. Hybridization probes were used to locate 23 genetic markers on the chromosomal map. Genetic polymorphism within strain A054 was analyzed by comparing the macrorestric...

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Section: Sf3supporting

confidence: 72%

Section: Sf3supporting

confidence: 69%

Section: Sf3mentioning

confidence: 90%

Section: Sf3mentioning

confidence: 99%

mentioning

confidence: 99%

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Physical and genetic map of Streptococcus thermophilus A054

Roussel¹,

Pébay²,

Guédon³

et al. 1994

J Bacteriol

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16S-23S and 23S-5S intergenic spacer regions of Streptococcus thermophilus and Streptococcus salivarius, primary and secondary structure

Nour

Naimi

Beck

et al. 1995

Current Microbiology

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The 16S-23S intergenic spacer region (spacer region 1) of Streptococcus salivarius, S. thermophilus, and Lactococcus lactis subsp. cremoris and the 23S-5S intergenic spacer region (spacer region 2) of S. salivarius and L. lactis subsp. cremoris were sequenced and compared with the spacer regions 1 and 2 of other streptococci. A high degree of intraspecific conservation was observed for S. thermophilus and L. lactis, and very similar sequences were found for S. salivarius and S. thermophilus. Whereas spacer region 1 is highly conserved in the genus Streptococcus sensu-stricto, only the tRNA gene and the rRNA processing stems are highly conserved in the three genera: Streptococcus sensu-stricto, Lactococcus, and Enterococcus. The presence of a unique tRNA(Ala) gene without the 3' terminal CCA sequence seems to be a general feature of the streptococci spacer region 1. A secondary structure model was built to show the interaction between the spacer regions 1 and 2 of S. thermophilus and S. salivarius. The rapid evolution of spacer region 1 in streptococci is in part due to insertions and deletions of small RNA stem/loop structures.

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