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Group II intron protein localization and insertion sites are affected by polyphosphate
Junhua Zhao1, Wei Niu, Jun Yao
1Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America.
Plos Biology
|July 3, 2008
Summary
Mobile group II introns use intron-encoded proteins to integrate into DNA. Polyphosphate accumulation disrupts this protein
Area of Science:
- Molecular Biology
- Microbial Genetics
- Biochemistry
Background:
- Mobile group II introns utilize intron-encoded proteins and RNA to facilitate DNA integration.
- The Lactococcus lactis Ll.LtrB intron-encoded protein (LtrA) typically localizes to bacterial cellular poles.
Purpose of the Study:
- To identify bacterial genes affecting LtrA localization and Ll.LtrB insertion site preference.
- To elucidate the mechanism controlling LtrA localization and its impact on intron mobility.
Main Methods:
- Screening of a transposon-insertion library using cell microarrays and automated fluorescence microscopy.
- Analysis of LtrA localization patterns and Ll.LtrB insertion site distribution in mutant strains.
Main Results:
- Disruption of five specific E. coli genes led to more diffuse LtrA localization and uniform genomic insertion.
- Intracellular polyphosphate accumulation was identified as a key factor delocalizing LtrA from cellular poles.
- Polyphosphate binds to LtrA and other basic proteins, altering their cellular distribution.
Conclusions:
- Intracellular protein localization is a critical determinant of group II intron insertion-site preference.
- Polyphosphate accumulation may regulate protein localization during cellular stress or stationary phase.
- This mechanism has potential implications for various physiological processes in bacteria.
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