Staphylococcus aureus N315
open/close allAbout this Microorganism
Staphylococcus aureus N315 was isolated as an MRSA (methicillin-resistant S. aureus) that was a major pathogen causing hospital-acquired infections in 1982. This bacterium is easy to acquire antibiotic-resistance, even to vancomycin that is said to be a last hope of drug to cure MRSA-infected patients. Analysis of the genome of S. aureus N315 is expected to enhance the accuracy of detection of Staphylococcal infections as well as to reduce the time for detection. Furthermore, it is expected that the mechanisms of antibiotic-resistance will be further investigated so as to develop new methods and techniques to combat with MRSA.
Results of the genome analysis of S. aureus N315 indicate that it contains a plasmid of 25 kb in size. Its genome size is 2.81 Mb with a 32.8 % G+C content, 20 copies of insertion sequences and five transposons. There are three 'pathogenicity islands' within the genome. With a few characteristic exceptions such as the genes involved in sporulation in Bacillus subtilis or those involved in toxin production in S. aureus N315, the numbers of genes in various functional categories are very similar between the two bacteria.
Project history
Last annotation update: 2009-02-05
2007-04-06Summary of the genomic data
| Genomic size | 2,839,469 bp | ||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| G+C content | 32.81 % | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Number of ORFs assigned | 2,624 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Percentage of the coding regions | 84.34 % | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Percentage of the intronic regions | 0.00 % | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Number of rRNA genes |
16
|
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| Number of tRNA genes |
62
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| Number of other features (misc_RNA,misc_feature,repeat) |
0 |
General Procedure
The entire nucleotide sequence of the S. aureus N315 genome was determined by the whole-genome shotgun (WGS) method as described below.
- A WGS clone library was prepared in E. coli DH5-alpha-MCR by preparing genomic DNA fragments of S. aureus N315 and cloning them into pUC18 plasmid.
- The WGS clones were randomly sequenced by using the dye-terminator kit and analyzed in PRISM 3700 DNA Analyzers of ABI.
- The raw sequence data thus obtained were assembled by using Phred/Phrap. The assembled sequencing data were subsequently split into 50-kb regions and reassembled and edited by Sequencher.
- Gaps between contigs were amplified by PCR using primers placed at the ends of individual contigs and sequenced.
- Confirmation of the nucleotide sequence was achieved by performing PCR walking of every 18-kb region of the genome.
- ORFs encoding proteins with 30 aa or more were identified with GAMBLER (http://bio.mki.co.jp/en/) and GLIMMER.
- The predicted ORFs were examined with respect to their start-codon assignment and some overlapping ORFs were removed.
- The homology of the ORFs were then searched for against a non-redundant protein database using BLAST.
- Functional motifs and domains of the deduced proteins were searched for against Prosite, Blocks, Pfam and PSORT.
- The tRNA and tmRNA genes were identified, respectively, by tRNAscan-SE or by the procedure described (http://www.indiana.edu/~tmrna/).
We thank Dr. Enrique D. Vines, University of Western Ontario for letting us know about his study.