Characterization of HCF-1, a determinant of Autographa californica multiple nucleopolyhedrovirus host specificity.

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) infects a wide variety of insect species. A number of AcMNPV late expression factors that are involved in replication have been identified as playing a role in determining host specificity. Host cell factor-1, or HCF-1, was previously demonstrated to be essential for viral replication in Tn-368 cells. Here we demonstrate that HCF-1 is an early protein and localizes to the cell nucleus. Coprecipitation experiments revealed that HCF-1 interacts with itself but none of the other late expression factors required for replication in Tn-368 cells. HCF-1 mutants were constructed and utilized to search for the domains involved in HCF-1 biological function and oligomerization. Possible roles of HCF-1 in determining host specificity are discussed.