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Mutations altering chromosomal protein H-NS induce mini-Mu transposition.
M Falconi1, V McGovern, C Gualerzi
1Department of Biochemistry, University of Alabama, Birmingham 35294.
The New Biologist
|June 1, 1991
Summary
Host factor H-NS regulates bacteriophage Mu transposition. Mutations in hns significantly increase MudII1681 transposition rates, indicating H-NS
Area of Science:
- Bacteriology
- Molecular Biology
- Genetics
Background:
- Bacteriophage Mu is a highly efficient transposon, capable of rapid integration into bacterial chromosomes.
- Defective phage MudII1681 can transpose and replicate but lacks genes for packaging and lysis.
- Spontaneous transposition frequency of MudII1681 changes with colony age.
Purpose of the Study:
- To identify host genes influencing spontaneous Mu transposition frequency.
- To investigate the role of H-NS protein in regulating Mu transposition.
Main Methods:
- Utilized a genetic screen employing mini-MudlacZ fusions to assay transposition frequency.
- Investigated the effect of mutations in the hns gene on MudII1681 transposition.
- Examined the in vitro interaction of purified H-NS with Mu repressor-DNA complexes.
Main Results:
- Mutations in the hns gene led to increased Mu-specific transcription.
- A significant increase in MudII1681 transposition rates was observed under specific growth conditions in hns mutants.
- Purified H-NS protein stabilized Mu repressor-DNA complexes in vitro.
Conclusions:
- H-NS (histone-like nucleoid-structuring protein) plays a crucial role in modulating bacteriophage Mu transposition.
- H-NS likely contributes to the organization of transcriptionally silent DNA, thereby repressing Mu transposition.
- Understanding H-NS function provides insights into the regulation of mobile genetic elements in bacteria.