Genetic Determinants of the Synthesis of the Polysaccharide Capsular Antigen K27(A) of Escherichia coli

Schmidt, G.; Jann, Barbara; Jann, Klaus; Ørskov, Ida; Ørskov, Frits

doi:10.1099/00221287-100-2-355

Cited by 22 publications

(11 citation statements)

References 13 publications

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“…The genes required for biosynthesis of the 09 and K30 polysaccharides are designated ribo9 and cpsK30, respectively. These genes are closely linked and are located near the his locus on the chromosome; linkage experiments suggest that the gene order is his-rfb09-cpsK30 (30,50,58). E. coli strains with group IA K antigens do not produce colanic acid (23), and the cpsK30 gene cluster appears to be allelic with CPSK12 genes required for colanic acid production in E. coli K-12 (26).…”

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Cloning and analysis of duplicated rfbM and rfbK genes involved in the formation of GDP-mannose in Escherichia coli O9:K30 and participation of rfb genes in the synthesis of the group I K30 capsular polysaccharide

et al. 1994

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The rfbg,, gene cluster, which is responsible for the synthesis of the lipopolysaccharide 09 antigen, was cloned from Escherichia coi 09:130. The gnd gene, encoding 6-phosphogluconate dehydrogenase, was identified adjacent to the rJb09 cluster, and by DNA sequence analysis the gene order gnd-rJbM-rjbK was established. This order differs from that described for other members of the family Enterobacteriaceae.Nucleotide sequence analysis was used to identify the rftK and rJbM genes, encoding phosphomannomutase and GDP-mannose pyrophosphorylase, respectively. In members of the family Enterobacteriaceae, these enzymes act sequentially to form GDP-mannose, which serves as the activated sugar nucleotide precursor for mannose residues in cell surface polysaccharides. In the E. coli 09:K30 strain, a duplicated rJbM2-rJbK2 region was detected approximately 3 kbp downstream of rJbM'-dbK' and adjacent to the remaining genes of the rib09cluster. The rJbM isogenes differed in upstream flanking DNA but were otherwise highly conserved. In contrast, the rfbK isogenes differed in downstream flanking DNA and in 3'-terminal regions, resulting in slight differences in the sizes of the predicted RfbK proteins. RfbMog and RfbKog are most closely related to CpsB and CpsG, respectively. These are isozymes of GDP-mannose pyrophosphorylase and phosphomannomutase, respectively, which are thought to be involved in the biosynthesis of the slime polysaccharide colanic acid in E. coi K-12 and Salmonella enterica serovar Typhimurium. An E. col 0-:K30 mutant, strain CWG44, lacks rJbM2-rJb0K2 and has adjacent essential rib09 sequences deleted. The remaining chromosomal genes are therefore suflicieift for GDP-mannose formation and K30 capsular polysaccharide synthesis. A mutant of E. coli CWG44, strain CWG152, was found to lack GDP-anannose pyrophosphorylase and lost the ability to synthesize K30 capsular polysaccharide. Wild

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Cloning and analysis of duplicated rfbM and rfbK genes involved in the formation of GDP-mannose in Escherichia coli O9:K30 and participation of rfb genes in the synthesis of the group I K30 capsular polysaccharide

et al. 1994

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“…Colanic acid shares features with the group I E. coli capsular K antigens, including superficial structural and compositional similarities (18,33) and the location of the biosynthetic cps gene cluster near the his genes (36,53,61,66). We have recently shown that E. coli K30, a strain with a prototype group I capsule, does not synthesize colanic acid and that the biosynthesis genes for the K30 CPS and colanic acid may be allelic (31).…”

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Characterization of rcsB and rcsC from Escherichia coli O9:K30:H12 and examination of the role of the rcs regulatory system in expression of group I capsular polysaccharides

et al. 1993

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“…The organization and functions encoded by serA-linked kps genes that are responsible for expression of group II K antigens have been researched quite extensively (reviewed in references 6, 18, 46, and 55). However, other than the fact that the cps genes for biosynthesis of group IA K antigens map near the his and rfb (O-antigen biosynthesis) loci (29,45,54), little is known about their organization or the functions of their gene products. The cps genes for group IB strains have not yet been mapped or characterized.…”

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Distribution of the rol gene encoding the regulator of lipopolysaccharide O-chain length in Escherichia coli and its influence on the expression of group I capsular K antigens

1996

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The rol (cld) gene encodes a protein involved in the expression of lipopolysaccharides in some members of the family Enterobacteriaceae. Rol interacts with one or more components of Rfc-dependent O-antigen biosynthetic complexes to regulate the chain length of lipopolysaccharide O antigens. The Rfc-Rol-dependent pathway for O-antigen synthesis is found in strains with heteropolysaccharide O antigens, and, consistent with this association, rol-homologous sequences were detected in chromosomal DNAs from 17 different serotypes with heteropolysaccharide O antigens. Homopolymer O antigens are synthesized by a pathway that does not involve either Rfc or Rol. It was therefore unexpected when a survey of Escherichia coli strains possessing mannose homopolymer O8 and O9 antigens showed that some strains contained rol. All 11 rol-positive strains coexpressed a group IB capsular K antigen with the O8 or O9 antigen. In contrast, 12 rol-negative strains all produced group IA K antigens in addition to the homopolymer O antigen. Previous research from this and other laboratories has shown that portions of the group I K antigens are attached to lipopolysaccharide lipid A-core, in a form that we have designated K LPS . By constructing a hybrid strain with a deep rough rfa defect, it was shown that the K40 (group IB) K LPS antigen exists primarily as long chains. However, a significant amount of K40 antigen was surface expressed in a lipid A-core-independent pathway. The typical chain length distribution of the K40 antigen was altered by introduction of multicopy rol, suggesting that the K40 group IB K antigen is equivalent to a Rol-dependent O antigen. The prototype K30 (group IA) K antigen is expressed as short oligosaccharides (primarily single repeat units) in K LPS , as well as a high-molecular-weight lipid A-core-independent form. Introduction of multicopy rol into the K30 strain generated a novel modal pattern of K LPS with longer polysaccharide chains. Collectively, these results suggested that group IA K LPS is also synthesized by a Rol-dependent pathway and that the typically short oligosaccharide K LPS results from the absence of Rol activity in these strains.

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Genetic Determinants of the Synthesis of the Polysaccharide Capsular Antigen K27(A) of Escherichia coli

Cited by 22 publications

References 13 publications

Cloning and analysis of duplicated rfbM and rfbK genes involved in the formation of GDP-mannose in Escherichia coli O9:K30 and participation of rfb genes in the synthesis of the group I K30 capsular polysaccharide

Cloning and analysis of duplicated rfbM and rfbK genes involved in the formation of GDP-mannose in Escherichia coli O9:K30 and participation of rfb genes in the synthesis of the group I K30 capsular polysaccharide

Characterization of rcsB and rcsC from Escherichia coli O9:K30:H12 and examination of the role of the rcs regulatory system in expression of group I capsular polysaccharides

Distribution of the rol gene encoding the regulator of lipopolysaccharide O-chain length in Escherichia coli and its influence on the expression of group I capsular K antigens

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