title: Acquisition of the capsule locus by horizontal gene transfer in Neisseria meningitidis is often accompanied by the loss of UDP-GalNAc synthesis.
abstract: Pathogenic meningococci have acquired a 24 kb capsule synthesis island (cps) by horizontal gene transfer which consists of a synthetic locus and associated capsule transport genes flanked by repetitive Regions D and D'. Regions D and D' contain an intact gene encoding a UDP-galactose epimerase (galE1) and a truncated remnant (galE2), respectively. In this study, GalE protein alleles were shown to be either mono-functional, synthesising UDP-galactose (UDP-Gal), or bi-functional, synthesising UDP-Gal and UDP-galactosamine (UDP-GalNAc). Meningococci possessing a capsule null locus (cnl) typically possessed a single bi-functional galE. Separation of functionality between galE1 and galE2 alleles in meningococcal isolates was retained for all serogroups except serogroup E which has a synthetic requirement for UDP-GalNAc. The truncated galE2 remnant in Region D' was also phylogenetically related to the bi-functional galE of the cnl locus suggesting common ancestry. A model is proposed in which the illegitimate recombination of the cps island into the galE allele of the cnl locus results in the formation of Region D' containing the truncated galE2 locus and the capture of the cps island en bloc. The retention of the duplicated Regions D and D' enables inversion of the synthetic locus within the cps island during bacterial growth.
authors.affiliation: School of Biomedical Sciences, University of Western Australia, Perth, Australia.|The Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Perth, Australia.|School of Molecular Sciences, University of Western Australia, Perth, Australia.
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: Bartley
authors.affiliation: School of Biomedical Sciences, University of Western Australia, Perth, Australia.|The Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Perth, Australia.
authors.forename: Shakeel
authors.initials: S
authors.lastname: Mowlaboccus
authors.affiliation: School of Biomedical Sciences, University of Western Australia, Perth, Australia.|The Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Perth, Australia.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Mullally
authors.affiliation: School of Molecular Sciences, University of Western Australia, Perth, Australia.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Stubbs
authors.affiliation: School of Molecular Sciences, University of Western Australia, Perth, Australia.
authors.forename: Alice
authors.initials: A
authors.lastname: Vrielink
authors.affiliation: University of Oxford, Department of Zoology, South Parks Road, Oxford OX1 3PS, United Kingdom.
authors.forename: Martin C J
authors.initials: MC
authors.lastname: Maiden
authors.affiliation: University of Oxford, Department of Zoology, South Parks Road, Oxford OX1 3PS, United Kingdom.
authors.forename: Odile B
authors.initials: OB
authors.lastname: Harrison
authors.affiliation: School of Biomedical Sciences, University of Western Australia, Perth, Australia.|The Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Perth, Australia.
authors.forename: Timothy T
authors.initials: TT
authors.lastname: Perkins
authors.affiliation: School of Biomedical Sciences, University of Western Australia, Perth, Australia.|The Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Perth, Australia.
authors.forename: Charlene M
authors.initials: CM
authors.lastname: Kahler
mesh_terms: D016667:Bacterial Capsules / Q000235:genetics; D022761:Gene Transfer, Horizontal / Q000235:genetics*; D006801:Humans; D008585:Meningitis, Meningococcal / Q000235:genetics* / Q000382:microbiology; D009345:Neisseria meningitidis / Q000235:genetics* / Q000472:pathogenicity; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D014534:UDPglucose 4-Epimerase / Q000235:genetics*; D014531:Uridine Diphosphate Galactose / Q000096:biosynthesis
chemical_list: D014531:Uridine Diphosphate Galactose; D014534:UDPglucose 4-Epimerase