RNA splicing factors regulated by HPV16 during cervical tumour progression

Abstract

The most prevalent human papillomaviruses (HPVs) causing cervical disease are the ‘high‐risk’ HPV types 16 and 18. All papillomaviruses express a transcription factor, E2, that can regulate viral and cellular gene expression. Recently, we demonstrated high‐risk HPV E2‐mediated transcriptional transactivation of SF2/ASF. This essential oncoprotein is a key member of a family of proteins, the SR proteins, that regulate constitutive and alternative splicing. Tight control of RNA splicing is necessary for the production of wild‐type proteins. So, aberrant expression of SR proteins is involved in the aetiology of a range of human diseases, including cancer. Here we demonstrate epithelial differentiation‐specific control of SF2/ASF in HPV16‐infected keratinocytes in organotypic raft culture and in low‐grade cervical lesions (CIN1). Further, we demonstrate HPV16 infection/differentiation‐induced up‐regulation of a specific subset of SR proteins and present evidence that HPV16 E2 controls expression of SRp20, SC35 and SRp75. Using a series of cell lines that model cervical tumour progression, we show that SF2/ASF, SRp20 and SC35 are specifically up‐regulated in a model of cervical tumour progression. These SR proteins are also over‐expressed in high‐grade cervical lesions, indicating that they may all have oncogenic functions. SR proteins could be useful biomarkers for HPV‐associated disease. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.