Interplay between CTHRC1 and the SU protein of avian leukosis virus subgroup J (ALV-J) facilitates viral replication

The lifecycle of avian leukosis virus subgroup J (ALV-J), a typical tumorigenic retrovirus, is highly dependent upon host cellular proteins. However, there have been few studies directed at uncovering the host proteins responsible for ALV-J replication, which could provide insights into new strategies for ALV-J prevention and control. Here, we used proteomics to identify the association of differential levels of collagen triple helix-repeat-containing 1 (CTHRC1) and with viral replication. Our results revealed that CTHRC1 was significantly upregulated in ALV-J-infected cells in vitro, and these findings were confirmed in vivo. Additionally, CTHRC1 over-expression facilitated ALV-J replication, whereas CTHRC1 knockdown suppressed this activity. Moreover, we found that ALV-J drove CTHRC1 translocation from the nucleus to the cytosol through interactions with the ALV-J envelope glycoprotein. These results revealed CTHRC1 as a shutting protein is recruited by ALV-J to facilitate viral replication.