Genetic analysis of the capsular biosynthetic locus from all 90 pneumococcal serotypes.
Several major invasive bacterial pathogens are encapsulated. Expression of a polysaccharide capsule is essential for survival in the blood, and thus for virulence, but also is a target for host antibodies and the basis for effective vaccines. Encapsulated species typically exhibit antigenic variation and express one of a number of immunochemically distinct capsular polysaccharides that define serotypes. We provide the sequences of the capsular biosynthetic genes of all 90 serotypes of Streptococcus pneumoniae and relate these to the known polysaccharide structures and patterns of immunological reactivity of typing sera, thereby providing the most complete understanding of the genetics and origins of bacterial polysaccharide diversity, laying the foundations for molecular serotyping. This is the first time, to our knowledge, that a complete repertoire of capsular biosynthetic genes has been available, enabling a holistic analysis of a bacterial polysaccharide biosynthesis system. Remarkably, the total size of alternative coding DNA at this one locus exceeds 1.8 Mbp, almost equivalent to the entire S. pneumoniae chromosomal complement.
Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom. sdb@sanger.ac.uk
Stephen D
SD
Bentley
David M
DM
Aanensen
Angeliki
A
Mavroidi
David
D
Saunders
Ester
E
Rabbinowitsch
Matthew
M
Collins
Kathy
K
Donohoe
David
D
Harris
Lee
L
Murphy
Michael A
MA
Quail
Gabby
G
Samuel
Ian C
IC
Skovsted
Margit Staum
MS
Kaltoft
Bart
B
Barrell
Peter R
PR
Reeves
Julian
J
Parkhill
Brian G
BG
Spratt
D016667:Bacterial Capsules / Q000737:chemistry; D019295:Computational Biology / Q000379:methods*; D005798:Genes, Bacterial; D016133:Polymerase Chain Reaction; D011134:Polysaccharides / Q000737:chemistry*; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000235:genetics*
D011134:Polysaccharides; D011135:Polysaccharides, Bacterial