Microbiology Procedure

Index >> Bacteriophages - Part Two >> Replication and Integration in Mu Phage

Replication and Integration in Mu Phage

	Replication and Integration in Mu Phage - As mentioned previously, Mu DNA bas heterogenous sequences of host DNA at its ends. These sequences are acquired from headful packaging of Mu DNA from maturation precursors. These consist of Mu DNA flanked by host sequences. The old host sequences are removed from phage DNA during integration.
Thus maturation precursors with new sequences are generated subsequently. A population of Mu phage particles contains different DNA with different end sequences which are randomized during Mu growth.
Mu DNA free from host DNA has not been detected. Replication of the DNA must therefore be taking place in situ. Replication, however, does not proceed into the host DNA. Incorporation of parental Mu DNA into host DNA is poor. This leads to the conclusion tbat copies of Mu DNA (replication products) must be taking part in integration.
	Thus replication is the key to integration. It might generate a form free of host DNA, which may be the active precursor for integration. Mu DNA resembles IS elements and transposons in many of its properties. Mu DNA can integrate on any site in the bacterial DNA. The bacterial gene in which the prophage is integrated is usually inactivated. The genes distal to the integration site are inactivated by the termination of transcription (polar effect).

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