title: PCR-based detection of composite transposons and translocatable units from oral metagenomic DNA.
abstract: A composite transposon is a mobile genetic element consisting of two insertion sequences (ISs) flanking a segment of cargo DNA often containing antibiotic resistance (AR) genes. Composite transposons can move as a discreet unit. There have been recently several reports on a novel mechanism of movement of an IS26-based composite transposon through the formation of a translocatable unit (TU), carrying the internal DNA segment of a composite transposon and one copy of a flanking IS. In this study, we determined the presence of composite transposons and TUs in human oral metagenomic DNA using PCR primers from common IS elements. Analysis of resulting amplicons showed four different IS1216 composite transposons and one IS257 composite transposon in our metagenomic sample. As our PCR strategy would also detect TUs, PCR was carried out to detect circular TUs predicted to originate from these composite transposons. We confirmed the presence of two novel TUs, one containing an experimentally proven antiseptic resistance gene and another containing a putative universal stress response protein (UspA) encoding gene. This is the first report of a PCR strategy to amplify the DNA segment on composite transposons and TUs in metagenomic DNA. This can be used to identify AR genes associated with a variety of mobile genetic elements from metagenomes.
authors: Department of Microbial Diseases, University College London, Eastman Dental Institute, 256 Gray's Inn Road, London WC1×8LD, UK.
authors: Supathep
authors: S
authors: Tansirichaiya
authors: Department of Microbial Diseases, University College London, Eastman Dental Institute, 256 Gray's Inn Road, London WC1×8LD, UK.
authors: Peter
authors: P
authors: Mullany
authors: Department of Microbial Diseases, University College London, Eastman Dental Institute, 256 Gray's Inn Road, London WC1×8LD, UK adam.roberts@ucl.ac.uk.
authors: Adam P
authors: AP
authors: Roberts
mesh_terms: D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D054892:Metagenome; D056186:Metagenomics / Q000379:methods; D009055:Mouth / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D012463:Saliva / Q000166:cytology; D017422:Sequence Analysis, DNA
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial
keywords: composite transposon; oral metagenomic DNA; translocatable unit (TU)