| Autor: |
Isa NF; Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.; Research Unit for Bioinformatics and Computational Biology, Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia, Kuantan 25200, Pahang, Malaysia., Bensaude O; Ecole Normale Supérieure, Institut de Biologie de l'Ecole Normale Supérieure, PSL Research University, CNRS UMR 8197, INSERM U 1024, F-75005 Paris, France., Aziz NC; Research Unit for Bioinformatics and Computational Biology, Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia, Kuantan 25200, Pahang, Malaysia., Murphy S; Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK. |
| Abstrakt: |
The Herpes Simplex Virus (HSV-1) immediate-early protein ICP22 interacts with cellular proteins to inhibit host cell gene expression and promote viral gene expression. ICP22 inhibits phosphorylation of Ser2 of the RNA polymerase II (pol II) carboxyl-terminal domain (CTD) and productive elongation of pol II. Here we show that ICP22 affects elongation of pol II through both the early-elongation checkpoint and the poly(A)-associated elongation checkpoint of a protein-coding gene model. Coimmunoprecipitation assays using tagged ICP22 expressed in human cells and pulldown assays with recombinant ICP22 in vitro coupled with mass spectrometry identify transcription elongation factors, including P-TEFb, additional CTD kinases and the FACT complex as interacting cellular factors. Using a photoreactive amino acid incorporated into ICP22, we found that L191, Y230 and C225 crosslink to both subunits of the FACT complex in cells. Our findings indicate that ICP22 interacts with critical elongation regulators to inhibit transcription elongation of cellular genes, which may be vital for HSV-1 pathogenesis. We also show that the HSV viral activator, VP16, has a region of structural similarity to the ICP22 region that interacts with elongation factors, suggesting a model where VP16 competes with ICP22 to deliver elongation factors to viral genes. |
