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IS406 and IS407, two gene-activating insertion sequences for Pseudomonas cepacia
M S Wood1, A Byrne, T G Lessie
1Department of Microbiology, University of Massachusetts, Amherst 01003.
Gene
|August 30, 1991
Summary
Researchers sequenced two insertion sequences (IS), IS406 and IS407, from Pseudomonas cepacia. These elements activate lac gene expression and create target DNA duplications upon insertion, offering insights into bacterial genetics.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Insertion sequences (IS) are mobile genetic elements that can influence gene expression.
- Pseudomonas cepacia is a bacterium known for its genetic adaptability.
- Tn951 contains lac genes whose expression can be modulated by IS elements.
Purpose of the Study:
- To determine the nucleotide sequences of IS406 and IS407.
- To investigate the ability of IS406 and IS407 to activate lac gene expression.
- To characterize the insertion properties and structural features of these IS elements.
Main Methods:
- Nucleotide sequencing of IS406 and IS407.
- Insertion of IS elements into the lac promoter/operator region of Tn951.
- Analysis of terminal inverted repeat (IR) sequences and flanking target DNA duplications.
Main Results:
- The nucleotide sequences of IS406 (1368 bp) and IS407 (1236 bp) were determined.
- IS406 and IS407 induced duplications of 8 bp and 4 bp of target DNA, respectively.
- IS406 possessed 41-bp terminal IRs with mismatches, including a motif found in Tn2501.
- IS407 featured 49-bp terminal IRs with mismatches and an outward-directed sigma 70-like promoter, showing relatedness to IS476 and ISR1.
Conclusions:
- IS406 and IS407 are novel insertion sequences with distinct structural characteristics.
- These IS elements can activate gene expression and mediate target DNA modification.
- The findings contribute to understanding the diversity and functional roles of bacterial IS elements.