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Streptococcus pneumoniae strain R6 is sequenced
Edward R. Winstead

Researchers have sequenced the R6 strain of Streptococcus pneumoniae, a non-virulent cousin of the pathogen that causes pneumonia, blood infections, and meningitis. Researchers around the world use the R6 strain to study S. pneumoniae because it is harmless and has a genome that is easily manipulated. Deleting genes from R6 or inserting genes from other bacteria is relatively straightforward, making the organism a useful investigative tool.

"The essential utility of the strain is its genetic malleability," the researchers write in the Journal of Bacteriology. The project was a partnership between Eli Lilly and Company, in Indianapolis, Indiana, and Incyte Genomics, of Palo Alto, California.

The R6 genome includes 2 million base pairs. A large number of the proteins predicted by the genome sequence reside on the cell surface or are secreted from the cell. These proteins interest drug makers because they may be more accessible targets than proteins inside the cell.

The R6 sequence is the third published S. pneumoniae genome this year. In July, The Institute for Genomic Research (TIGR) in Rockville, Maryland, reported the sequence of a virulent strain called TIGR4. A month earlier, researchers at GlaxoSmithKline S.A. in Tres Cantos, Spain, published the draft sequence of a S. pneumoniae 19F clinical isolate.

"It was very gratifying to see from the order of genes that the Lilly/Incyte and TIGR genomes independently confirmed the other's sequence," says John I. Glass, of Lilly, who led the research. His group is currently collaborating with TIGR researchers on a comparative analysis of the two genomes.

The R6 strain is derived from the strain used in the 1940s to show that DNA is the genetic material of life.

See related GNN article
»Sugar Transporters and Foreign DNA: The sequenced Streptococcus pneumoniae genome

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Hoskins, J. et al. Genome of the bacterium Streptococcus pneumoniae strain R6. J Bacteriol 183, 5709-5717 (October 2001).
Tettelin, H. et al. Complete genome sequence of a virulent isolate of Streptococcus pneumoniae. Science 293, 498-506 (July 20, 2001).
Dopazo, J. et al. Annotated draft genomic sequence from a Streptococcus pneumoniae type 19F clinical isolate. Microb Drug Resist 7, 99-125 (Summer 2001).

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