Fundamentals of Molecular Biology - V.I. Rezyapkin 2009

Genome Rearrangements
Lysogeny

Lysogeny refers to the ability of a phage to exist within a bacterial Cell as a prophage integrated into the bacterial genome (Fig. 9.17). A bacterial genome may harbor prophages from multiple phages simultaneously; this phenomenon is known as polylysogeny.

Following the infection of a bacterial cell by a phage, the infection can proceed via two pathways:

a) the lytic cycle pathway, which culminates in cell lysis and the release of numerous progeny phages into the environment;

b) the lysogenization pathway, where the phage DNA integrates into the bacterial DNA (Fig. 9.17) and replicates along with it during Bacterial Cell Division.

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Fig. 9.17. During lysogenization, phage DNA is integrated into the chromosome

Lysogenization can lead to altered bacterial properties due to the acquisition of novel Genetic information by the bacterium.

A bacterial cell can switch from the lysogenic pathway to the lytic cycle. In this case, the phage genome is excised from the bacterial genome, replicated, and gives rise to numerous Viral Particles that are released into the environment upon cell lysis.

In a small fraction of the progeny of a lysogenic cell, the prophage may be lost, resulting in cell “curing”.