Genetics of capsule O-acetylation in serogroup C, W-135 and Y meningococci.
Capsular polysaccharides of serogroup C, W-135 and Y meningococci were previously reported to be O-acetylated at the sialic acid residues. There is evidence that O-acetylation affects the immunogenicity of polysaccharide vaccines. We identified genes indispensable for O-acetylation of serogroup C, W-135 and Y meningococci downstream of the capsule synthesis genes siaA-D. The genes were co-transcribed with the sia operon as shown by reverse transcription polymerase chain reaction analysis. The putative capsular polysaccharide O-acetyltransferases were designated OatC and OatWY. The protein OatWY of serogroups W-135 and Y showed sequence homologies to members of the NodL-LacA-CysE family of bacterial acetyltransferases, whereas no sequence homology with any known protein in the different databases was found for the serogroup C protein OatC. In serogroup W-135 and Y meningococci, several clonal lineages either lacked OatWY or OatWY was inactivated by insertion of IS1301. For serogroup C meningococci, we observed in vitro phase variation of O-acetylation, which resulted from slipped-strand mispairing in homopolymeric tracts. This finding explains the observation of naturally occurring de-O-acetylated serogroup C meningococci. Our report is the first description of sequences of sialic acid O-acetyltransferase genes that have not been cloned from either other bacterial or mammalian organisms.
Claus
Heike
H
Institut für Hygiene und Mikrobiologie, Universität Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany. hclaus@hygiene.uni-wuerzburg.de
Borrow
Ray
R
Achtman
Mark
M
Morelli
Giovanna
G
Kantelberg
Carmen
C
Longworth
Emma
E
Frosch
Matthias
M
Vogel
Ulrich
U
D000107:Acetylation; D000123:Acetyltransferases / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D005784:Gene Amplification; D005798:Genes, Bacterial; D005843:Geography; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000145:classification / Q000235:genetics; D038542:Neisseria meningitidis, Serogroup C / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D038582:Neisseria meningitidis, Serogroup W-135 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D011134:Polysaccharides / Q000737:chemistry / Q000235:genetics; D011995:Recombination, Genetic; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012703:Serotyping
D011134:Polysaccharides; D000123:Acetyltransferases