Kiwa

Contributors: Lucas Paoli

Description

The Kiwa antiviral defense system was first described in () and further described in () . It is named after one of the divine guardians of the ocean in the Māori traditions. Kiwa is composed of two proteins: KwaA and KwaB.

Molecular mechanisms

KwaA detects phage infection by detecting the inhibition of the host RNA polymerase by phages. This triggers the response by KwaB, which decreases phage DNA replication through a RecBCD-dependent pathway () .

Example of genomic structure

The Kiwa is composed of 2 proteins: KwaA and KwaB.

Here is an example found in the RefSeq database:

The Kiwa system in Dickeya zeae (GCF_019464635.1, NZ_CP040817) is composed of 2 proteins KwaA (WP_038908257.1) KwaB_2 (WP_192991081.1)

Distribution of the system among prokaryotes

Among the 22,803 complete genomes of RefSeq, the Kiwa is detected in 1095 genomes (4.8 %).

The system was detected in 382 different species.

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

Structure

Kiwa

Example 1

Experimental validation

      
graph LR;
    Doron_2018[Doron et al., 2018] --> Origin_0
    Origin_0[Escherichia coli 
AEZ43441.1, AEZ43440.1] --> Expressed_0[Escherichia coli]
    Expressed_0[Escherichia coli] ----> LambdaVir & SECphi18
    subgraph Title1[Reference]
        Doron_2018
end
    subgraph Title2[System origin]
        Origin_0
end
    subgraph Title3[Expression species]
        Expressed_0
end
    subgraph Title4[Protects against]
        LambdaVir
        SECphi18
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

10.1126/science.aar4120
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10.1101/2023.02.26.530102
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