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

Autor: Nicolas Buisine, Ronald Chalmers, Azeem Siddique
Jazyk: angličtina
Rok vydání: 2011
Předmět:
Transposable element
Cancer Research
Genome evolution
Transcription
Genetic
lcsh:QH426-470
Gene prediction
Molecular Sequence Data
Population
Locus (genetics)
Meningitis
Meningococcal
Neisseria meningitidis
Biology
Polymorphism
Single Nucleotide
Genome
Evolution
Molecular
Infectious Diseases/Bacterial Infections
03 medical and health sciences
Genetics
Humans
Genetics and Genomics/Genomics
Promoter Regions
Genetic
education
Molecular Biology
Genetics (clinical)
Ecology
Evolution
Behavior and Systematics
Repetitive Sequences
Nucleic Acid
030304 developmental biology
Recombination
Genetic
Molecular Biology/Recombination
Phase variation
0303 health sciences
education.field_of_study
Base Sequence
030306 microbiology
Computational Biology
Genetics and Genomics
Promoter
Gene Expression Regulation
Bacterial
Genetics and Genomics/Microbial Evolution and Genomics
Neisseria gonorrhoeae
lcsh:Genetics
DNA Transposable Elements
RNA
Small Untranslated
Genetics and Genomics/Gene Discovery
Genome
Bacterial
Research Article
Zdroj: PLoS Genetics, Vol 7, Iss 1, p e1001277 (2011)
PLoS Genetics
ISSN: 1553-7390
Popis: 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.
Author Summary Transposons are mobile DNA elements that can jump from one location in the genome to another. They have had a profound influence on the evolutionary history of most, if not all, organisms by rearranging the order of genes and changing their expression patterns. The mariner family of transposons is probably the most successful group if judged by the breadth and depth of its phylogenetic distribution. One example is the Correia element, which has been amplified to a few hundred copies in Neisseria meningitidis. Transposons often encode promoters that drive the expression of adjacent genes. This raises the question of whether the large numbers of Correia elements in N. meningitidis have a significant genome-wide role in the control of gene expression. This is an interesting issue because N. meningitidis has evolved recently, having been first recognized in the 19th century, and is probably undergoing a period of rapid adaptation. Here we present a systematic analysis that defines eight sub-classes of Correia elements. We show that two subtypes encode strong promoters. The differential distribution of the strongest Correia promoter in the three strains provides a snapshot of evolution in action and sheds new light on the role of dispersed repeats in bacterial genomes.
Databáze: OpenAIRE
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