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The transposon-like correia elements encode numerous strong promoters and provide a potential new mechanism for phase variation in the meningococcus

Siddique, Azeem; Buisine, Nicolas; Chalmers, Ronald

Authors

Azeem Siddique

Nicolas Buisine

Ronald Chalmers

Abstract

Neisseria meningitidis is the primary causative agent of bacterial meningitis. The genome is rich in repetitive DNA and almost 2% is occupied by a diminutive transposon called the Correia element. Here we report a bioinformatic analysis defining eight subtypes of the element with four distinct types of ends. Transcriptional analysis, using PCR and a lacZ reporter system, revealed that two ends in particular encode strong promoters. The activity of the strongest promoter is dictated by a recurrent polymorphism (Y128) at the right end of the element. We highlight examples of elements that appear to drive transcription of adjacent genes and others that may express small non-coding RNAs. Pair-wise comparisons between three meningococcal genomes revealed that no more than two-thirds of Correia elements maintain their subtype at any particular locus. This is due to recombinational class switching between elements in a single strain. Upon switching subtype, a new allele is available to spread through the population by natural transformation. This process may represent a hitherto unrecognized mechanism for phase variation in the meningococcus. We conclude that the strain-to-strain variability of the Correia elements, and the large number of strong promoters encoded by them, allows for potentially widespread effects within the population as a whole. By defining the strength of the promoters encoded by the eight subtypes of Correia ends, we provide a resource that allows the transcriptional effects of a particular subtype at a given locus to be predicted.

Journal Article Type Article
Publication Date Jan 20, 2011
Journal PLoS Genetics
Print ISSN 1553-7390
Electronic ISSN 1553-7390
Publisher Public Library of Science
Peer Reviewed Peer Reviewed
Volume 7
Issue 1
Article Number 13
Institution Citation Siddique, A., Buisine, N., & Chalmers, R. (2011). The transposon-like correia elements encode numerous strong promoters and provide a potential new mechanism for phase variation in the meningococcus. PLoS Genetics, 7(1), doi:10.1371/journal.pgen.1001277
DOI https://doi.org/10.1371/journal.pgen.1001277
Publisher URL http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1001277
Copyright Statement Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0




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