Events following prophage Mu induction.

Area of Science:

• Bacteriology
• Molecular Biology
• Genetics

Background:

• Escherichia coli lysogenic for Mu cts62 prophage exhibit thermoinducible lysis.
• Prophage induction leads to host DNA damage and extensive Mu DNA replication and integration.

Purpose of the Study:

• To investigate the mechanism of Mu prophage-induced host DNA damage and lysis.
• To characterize the role of Mu genes in host sequence alteration.
• To analyze Mu DNA integration patterns during the lytic cycle.

Main Methods:

• Heat induction of Mu cts62 prophage in Escherichia coli.
• Analysis of host DNA damage and Mu gene expression.
• Detection of Mu DNA reintegration using episome rescue and transfer to F- recipient cells.

Main Results:

• Mu cts62 induction triggers rapid host cell lysis within 50 minutes.
• Expression of Mu A, BU, and X genes is critical for host sequence damage.
• Extensive Mu DNA reintegration occurs at multiple sites on the host genome.
• Approximately 10 copies of Mu DNA are inserted per chromosome during vegetative growth.

Conclusions:

• Mu prophage induction causes specific host DNA damage mediated by Mu gene products.
• Mu DNA undergoes extensive, multi-site integration into the host genome during its lytic cycle.
• The episome rescue method facilitates the study of Mu integration and isolation of Mu insertions.