Inhibitory activity of the human papillomavirus type 1 AU-rich element correlates inversely with the levels of the elav-like HuR protein in the cell cytoplasm

We have analysed the activity of the negative element in the late 3' untranslated region of the cutaneous human papillomavirus type 1 (HPV-1) mRNAs in a panel of epithelial cells, of both mucosal and cutaneous origin. The inhibitory activity was cell line dependent. Determination of the levels of heterogeneous ribonucleoprotein C1/C2 and HuR that have been shown previously to interact specifically with the HPV-1 negative RNA element revealed that low levels of the HuR protein in the cytoplasmic fraction correlated with high inhibitory activity of the HPV-1 element, whereas cell lines displaying low inhibitory activity contained high levels of HuR in the cytoplasm. These results suggested that the HuR protein has a positive effect on HPV-1 late gene expression.