Characterization of the duck plague virus UL35 gene.

OBJECTIVE Previous study has demonstrated that the duck plague virus (DPV) UL35 gene can be expressed as a recombinant fusion protein, and the prepared antiserum has a high reactivity and specificity against the purified recombinant protein. In the present study, to elucidate the properties and functions of its encoding protein, the UL35 gene product (VP26) was identified by using the prepared rabbit polyclonal antiserum. METHODS Real-time PCR, Western blot and immunofluorescence analysis were used to determine the transcription and expression kinetics and subcellular localization of DPV VP26 in DPV-infected cells. RESULTS A protein of approximately 13 kDa that reacted with the antiserum was detected in immunoblot of DPV-infected cellular lysates. Real-time PCR and Western blot analysis of DPV-infected cells showed that VP26 was produced predominantly at the late stage of infection, its production was highly dependent on viral DNA synthesis, and the UL35 gene was regulated as a late viral gene, suggesting that the gene should be categorized as gamma2 class. Additionally, analysis of the association of DPV VP26 with purified virions revealed that VP26 was a component of extracellular mature DPV virions. Subcellular localization demonstrated that VP26 firstly localized in cytoplasm, then it transferred to the nucleus and aggregated in the punctate region of the nucleus in DPV-infected cells. CONCLUSION Taken together, these results will provide a foundation for further functional analysis of the DPV UL35 gene.