Pif

Contributors: Lucas Paoli

Description

The Pif system (Phage Inhibition by F factors) was first described by Morisson & Malamy () . The Pif region of the F plasmid inhibits the phage T7 through abortive infection (, ) .

Molecular mechanisms

PifA was later identified as the effector of the abortive infection (, ) through nucleotide depletion by increased membrane permeability (also known as "leakage").

Example of genomic structure

The Pif is composed of 2 proteins: PifA and PifC.

Here is an example found in the RefSeq database:

The Pif system in Shigella flexneri (GCF_022353545.1, NZ_CP055168) is composed of 2 proteins PifC (WP_000952217.1) PifA (WP_000698737.1)

Distribution of the system among prokaryotes

Among the 22,803 complete genomes of RefSeq, the Pif is detected in 140 genomes (0.61 %).

The system was detected in 25 different species.

Proportion of genome encoding the Pif system for the 14 phyla with more than 50 genomes in the RefSeq database.

Structure

Pif

Example 1

Experimental validation

      
graph LR;
    Cheng_2004[Cheng et al., 2004] --> Origin_0
    Origin_0[Escherichia coli F-plasmid 
WP_028985935.1, WP_028985936.1] --> Expressed_0[Escherichia coli]
    Expressed_0[Escherichia coli] ----> T7
    subgraph Title1[Reference]
        Cheng_2004
end
    subgraph Title2[System origin]
        Origin_0
end
    subgraph Title3[Expression species]
        Expressed_0
end
    subgraph Title4[Protects against]
        T7
end
    style Title1 fill:none,stroke:none,stroke-width:none
    style Title2 fill:none,stroke:none,stroke-width:none
    style Title3 fill:none,stroke:none,stroke-width:none
    style Title4 fill:none,stroke:none,stroke-width:none

    

References

10.1007/BF00327934
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10.1016/j.virol.2004.06.001
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10.1128/jb.173.20.6507-6514.1991
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10.1038/newbio231037a0
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