HELB and infection: Interestingly, although PLEs 1 to 5 do not replicate during infection by ICP1 mutants lacking an accessory SF1B-type helicase (helA or helB) (29), PLE10 does replicate to low levels in the absence of this ICP1-encoded helicase (Fig. 3C), suggesting that the divergent replication module allows for additional flexibility in PLE’s reliance on ICP1’s replication machinery.