University of Kentucky
Effective Inhibition of TBSV Replication by Cellular TPR-domain Proteins
Institution
University of Kentucky
Faculty Advisor/ Mentor
Peter D. Nagy
Abstract
Viruses are a continuing threat to our society. Tomato bushy stunt tombusvirus (TBSV) is a (+)RNA virus that causes tomato to produce stunted fruit. This virus is used as a model to study virus replication and virus-host interactions based on yeast as a model host. TBSV utilizes two proteins to form a viral replicase complex: a RNA chaperone (p33) and a RNA-dependent RNA polymerase (p92pol). This complex is common to all (+)RNA viruses. This research has allowed for the screening of numerous cellular proteins for TBSV-host interaction. The above screens led to the identification of a new group of virus inhibitory factors, called cell-intrinsic restriction factors (CIRFs). Among the most potent CIRFs are the tetratricopeptide repeat (TPR, a 34 amino acid sequence) containing host proteins that greatly inhibit TBSV replication and assembly. The TPR motif interacts with TBSV when p92 binds to the co-opted cellular heat shock protein 70 (Hsp70). Our work has led to the identification of a series of TPR-containing proteins that inhibit tombusvirus replication and assembly. These proteins can be split into two groups: Hsp70/90 binding and non-Hsp70/90 binding. These TPR sequences have been tested in vitro and using a yeast two-hybrid system to measure protein-protein interaction between TPR and TBSV p92. The TPR sequences have also been tested for association and disassociation with viral factors using surface plasmon resonance. These findings give insight into the inhibitory role of TPR in TBSV replication. Future research may show how the TPR motif influences replication in other (+)RNA viruses.
Effective Inhibition of TBSV Replication by Cellular TPR-domain Proteins
Viruses are a continuing threat to our society. Tomato bushy stunt tombusvirus (TBSV) is a (+)RNA virus that causes tomato to produce stunted fruit. This virus is used as a model to study virus replication and virus-host interactions based on yeast as a model host. TBSV utilizes two proteins to form a viral replicase complex: a RNA chaperone (p33) and a RNA-dependent RNA polymerase (p92pol). This complex is common to all (+)RNA viruses. This research has allowed for the screening of numerous cellular proteins for TBSV-host interaction. The above screens led to the identification of a new group of virus inhibitory factors, called cell-intrinsic restriction factors (CIRFs). Among the most potent CIRFs are the tetratricopeptide repeat (TPR, a 34 amino acid sequence) containing host proteins that greatly inhibit TBSV replication and assembly. The TPR motif interacts with TBSV when p92 binds to the co-opted cellular heat shock protein 70 (Hsp70). Our work has led to the identification of a series of TPR-containing proteins that inhibit tombusvirus replication and assembly. These proteins can be split into two groups: Hsp70/90 binding and non-Hsp70/90 binding. These TPR sequences have been tested in vitro and using a yeast two-hybrid system to measure protein-protein interaction between TPR and TBSV p92. The TPR sequences have also been tested for association and disassociation with viral factors using surface plasmon resonance. These findings give insight into the inhibitory role of TPR in TBSV replication. Future research may show how the TPR motif influences replication in other (+)RNA viruses.