Related Experiment Videos
Involvement of heat shock proteins in bacteriophage Mu development
1Department of Molecular and Cellular Biology, National Jewish Center for Immunology, and Respiratory Medicine, Denver, Colorado.
Abstract:
Growth of bacteriophage Mu was severely inhibited at elevated temperature in mutants defective in the heat shock genes dnaK, groEL, and groES and in the rpoH (htpR) regulatory mutant, but not in mutants defective in the heat shock genes dnaJ or grpE; growth of a mutant of Mu deficient in functions encoded in the accessory region of the Mu genome was inhibited in the latter two host mutants. Phage production in the dnaJ mutant was restored by growth in low-salt medium. The stage in Mu development primarily affected in all except the groE mutants was phage late transcription. In contrast, the groE mutants did not support growth of Mu at any temperature; neither Mu DNA replication nor transcription was inhibited in these strains, suggesting that groE is required for phage morphogenesis as observed with several other coliphages.
Insights
Bacteriophage Mu growth is hindered at high temperatures in heat shock mutants, impacting late transcription. GroE mutants specifically block phage assembly, indicating its essential role in bacteriophage morphogenesis.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Bacteriophage Mu is a complex temperate bacteriophage.
- Bacterial heat shock proteins play crucial roles in cellular homeostasis and stress response.
- Understanding host-phage interactions under stress conditions is vital for molecular biology.
Purpose of the Study:
- To investigate the role of bacterial heat shock genes in the replication and development of bacteriophage Mu.
- To identify specific heat shock proteins essential for bacteriophage Mu late transcription and morphogenesis.
Main Methods:
- Utilizing bacterial mutants deficient in specific heat shock genes (dnaK, groEL, groES, dnaJ, grpE) and the rpoH regulatory gene.
- Assessing bacteriophage Mu growth and production at elevated temperatures.
- Analyzing bacteriophage Mu DNA replication and transcription stages.
- Evaluating the impact of host mutations on bacteriophage Mu accessory region functions.
Main Results:
- Bacteriophage Mu growth was severely inhibited at elevated temperatures in dnaK, groEL, groES, and rpoH mutants.
- Mutants defective in dnaJ and grpE showed less inhibition, but Mu accessory region mutants were affected in these hosts.
- Phage production in dnaJ mutants was restored in low-salt medium.
- Late transcription of bacteriophage Mu was the primary affected stage in most mutants, except groE.
- GroE mutants did not support Mu growth at any temperature, with no inhibition of Mu DNA replication or transcription.
Conclusions:
- Heat shock proteins dnaK, groEL, groES, and rpoH are critical for bacteriophage Mu growth, particularly affecting late transcription at elevated temperatures.
- GroE is essential for bacteriophage Mu morphogenesis, independent of its role in DNA replication or transcription.
- Specific host factors, including heat shock proteins and salt concentration, influence different stages of the bacteriophage Mu life cycle.