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Updated: Jun 8, 2026

Use of Interferon-γ Enzyme-linked Immunospot Assay to Characterize Novel T-cell Epitopes of Human Papillomavirus
Published on: March 8, 2012
The inhibitory action of P56 on select functions of E1 mediates interferon's effect on human papillomavirus DNA
Paramananda Saikia1, Volker Fensterl, Ganes C Sen
1Department of Molecular Genetics, NE20, Cleveland Clinic, 9500 Euclid Ave., Cleveland, OH 44195, USA.
Abstract:
The interferon (IFN)-induced protein P56 inhibits human papillomavirus (HPV) DNA replication by binding to HPV E1, which has several distinct functions in initiating viral DNA replication. Here, we determined that P56 inhibited HPV type 18 (HPV18) E1's DNA helicase activity, E2 binding, and HPV Ori sequence-specific DNA binding but not nonspecific DNA binding. We observed that deletion of a single amino acid, F399, produced an E1 mutant that could not bind P56. This E1 mutant retained its ability to support Ori DNA replication, but this activity was not inhibited by IFN, demonstrating that P56 is the principal executor of the anti-HPV action of IFN.
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