Identification and screening of host proteins interacting with ORFV-ORF047 protein.

Background: Orf virus (ORFV) is a member of the genus Parapoxvirus and family Poxviridae. The virus has a worldwide distribution and infects sheep, goats, humans, and wild animals. However, due to the complex structure of the poxvirus, the underlying mechanism of the entry and infection by ORFV remains largely unknown. ORFV ORF047 encodes a protein named L1R. Poxviral L1R serves as the receptor-binding protein and blocks virus binding and entry independently of glycosaminoglycans (GAGs). The study aimed to identify the host interaction partners of ORFV ORF047.

Methods: Yeast two-hybrid cDNA library of sheep testicular cells was applied to screen the host targets with ORF047 as the bait. ORF047 was cloned into a pBT3-N vector and expressed in the NMY51 yeast strain. Then, the expression of bait proteins was validated by Western blot analysis.

Results: Sheep SERP1and PABPC4 were identified as host target proteins of ORFV ORF047, and a Co-IP assay further verified their interaction.

Conclusions: New host cell proteins SERP1and PABPC4 were found to interact with ORFV ORF047 and might involve viral mRNA translation and replication.