Interaction of Daxx and human papillomavirus type 16 E2 protein

The aim of the study was to explore the interactions of human papilloma virus 16 (HPV16) E2 protein and Daxx. The localization or co-localization of PML and E2 with Daxx in Caski cells was observed by indirect immunofluorescence. The interaction of E2 and Daxx was analyzed by co-immunoprecipitation, Western-blot and yeast-two hybrid assays. In Caski cells the fluorescence of Daxx and PML was mainly distributed in the cytoplasm or nucleus, respectively, and in the align image their signals did not overlap. However, when the red signal of HPV16 E2 and the green signal of Daxx in the cytoplasm of Caski cells were merged, the yellow signal appeared. The yeast co-transformed with pGBKT7/Daxx and pGADT7/E2 or pGADT7/E2 TAD can grow on SD/-Trp-Leu-His and SD/-Trp-Leu-His-Ade plates. So Daxx is not colocated with PML but with HPV16 E2 mainly in the cytoplasm of Caski cells. On the base of the results one can propose that HPV16 E2, in particularly its transcription-activity domain (TAD), interacts with Daxx.