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IS1549 from Mycobacterium smegmatis forms long direct repeats upon insertion
B B Plikaytis1, J T Crawford, T M Shinnick
1Division of AIDS, STD, and TB Laboratory Research, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. bbp1@CDC.gov
Journal of Bacteriology
|March 12, 1998
Summary
A novel insertion element, IS1549, was discovered in Mycobacterium smegmatis. This element exhibits unique transposition characteristics, forming long direct repeats of target DNA and is found in specific M. smegmatis strains.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Insertion elements (IS) are mobile genetic components that can alter host genomes.
- IS elements play roles in gene regulation, genome evolution, and pathogenicity.
- Understanding novel IS elements is crucial for elucidating microbial genetic diversity.
Purpose of the Study:
- To identify and characterize a novel insertion element, designated IS1549, found in Mycobacterium smegmatis.
- To investigate the molecular features and transposition mechanism of IS1549.
- To determine the distribution of IS1549 within Mycobacterium species.
Main Methods:
- Whole-genome sequencing and bioinformatics analysis to identify IS1549.
- Sequence analysis to determine the open reading frame (ORF) and protein homology.
- Characterization of terminal inverted repeats and target DNA repeats.
- Southern blot and PCR to assess the prevalence of IS1549 in different strains and species.
Main Results:
- IS1549 is a 1,634-bp insertion element with a single ORF encoding a putative transposase distantly related to IS231 transposases.
- IS1549 possesses 11-bp terminal inverted repeats and generates long, variable-length direct repeats (71–246 bp) of target DNA during transposition.
- Five copies of IS1549 were detected in Mycobacterium smegmatis LR222.
- IS1549 is present in M. smegmatis strains with a specific PCR-restriction fragment length polymorphism type and is absent in other tested Mycobacterium species.
Conclusions:
- IS1549 represents a novel insertion element in M. smegmatis with distinct transpositional properties.
- The presence of IS1549 is strain-specific within M. smegmatis and does not appear to be widespread across other Mycobacterium species.
- Further research into IS1549 could provide insights into mycobacterial genome dynamics and evolution.