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Updated: Jun 12, 2026
14:07
Genome-wide Gene Deletions in Streptococcus sanguinis by High Throughput PCR
Published on: November 23, 2012
Simple sequence repeats and genome plasticity in Streptococcus agalactiae.
Robert Janulczyk1, Vega Masignani, Domenico Maione
1Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy. robert.janulczyk@novartis.com
Journal of Bacteriology
|May 25, 2010
Summary
Simple sequence repeats (SSRs) drive genome plasticity in Streptococcus agalactiae, a human pathogen. This study reveals SSR variation impacts gene expression and protein function, differing from Gram-negative bacteria strategies.
Area of Science:
- Microbiology
- Genomics
- Molecular Biology
Background:
- Simple sequence repeats (SSRs) are known to influence phase variation and adaptation in Gram-negative bacteria.
- Their role in Gram-positive pathogens like Streptococcus agalactiae remains less understood.
Purpose of the Study:
- To investigate the presence and impact of SSRs in the genome of Streptococcus agalactiae.
- To identify evidence of slipped-strand mispairing and its consequences in this human pathogen.
Main Methods:
- Comparative genomics was employed to screen SSRs across multiple Streptococcus agalactiae genomes.
- Analysis included identifying varying SSR loci, characterizing repeat types, and examining their genomic positions within open reading frames (ORFs).
Main Results:
- Over 2,200 SSRs were identified, with 56 exhibiting variation across seven genomes.
- Homopolymeric adenine tracts were the most frequent varying repeats, often located at the 5' ends of ORFs.
- Selective pressure against long homopolymeric tracts was observed, and altered phenotypes were confirmed for surface-attached proteins.
Conclusions:
- SSRs contribute significantly to the genome plasticity of Streptococcus agalactiae.
- The adaptive strategies employed via SSRs in this Gram-positive pathogen differ from those observed in Gram-negative organisms.
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