P1 phage

P1 is a temperate bacteriophage (phage). The P1 phage can be used to create the P1-derived artificial chromosome cloning vector.

Life cycle

Temperate phage, such as P1, have the ability to exist within the bacterial cell they infect in two different ways. In lysogeny, P1 can exist within a bacterial cell as a circular DNA in that it exists by replicating as if it were a plasmid and does not cause cell death. Alternatively, in its lytic phase, P1 can promote cell lysis during growth resulting in host cell death. During lysogeny new phage particles are not produced. In contrast, during lytic growth many new phage particles are assembled and released from the cell. By alternating between these two modes of infection, P1 can survive during extreme nutritional conditions that may be imposed upon the bacterial host in which it exists.

A unique feature of phage P1 is that during lysogeny its genome is not incorporated into the bacterial chromosome as is commonly observed during lysogeny of other bacteriophage. Instead, P1 exists independently within the bacterial cell, much like a plasmid would. P1 replicates as a 90 kilobase (kb) plasmid in the lysogenic state and is partitioned equally into two new daughter cells during normal cell division.

P1 encodes a site-specific recombinase, Cre, that is widely used to promote cell-specific or time-specific DNA recombination via flanking loxP sites

External links

• Viralzone: P1-like phage

This microbiology-related article is a stub. You can help Wikipedia by expanding it. v • d • e