Inefficient export of viral late mRNA contributes to fastidiousness of human adenovirus type 41 (HAdV-41) in 293 cells
The human adenovirus (HAdV) early protein E1B55K interacts with E4orf6 to form an E3 ubiquitin ligase complex, which plays key roles in virus replication. To illustrate the reason for the fastidiousness of HAdV-41 in 293 cells, interaction between heterotypic E1B55K and E4orf6 proteins was investigated. HAdV-5 E1B55K could interact with HAdV-41 E4orf6, and vice versa. To form E1B55K/E4orf6 E3 ubiquitin ligase, HAdV-41 E4orf6 recruited Cul2 while HAdV-5 E4orf6 interacted with Cul5. The ligase complex formed by HAdV-5 E1B55K and HAdV-41 E4orf6 could cause the degradation of p53 and Mre11. However, in E1-deleted HAdV-41-infected 293TE7 cells, which expressed HAdV-41 E1B55K, viral late mRNAs were exported from nucleus more efficiently and accumulated to a higher concentration in cytoplasm when compared with that in infected 293 cells. These results suggested that interaction between homotypic E1B55K and E4orf6 was indispensable for efficient export of viral late mRNAs. • Interactions between heterotypic E1B55K and E4orf6 proteins were investigated. • HAdV-5 E1B55K could interact with HAdV-41 E4orf6, and vice versa. • HAdV-5 E1B55K/HAdV-41 E4orf6 ligase complex caused degradation of p53 and Mre11. • HAdV-41 E1B55K/HAdV-41 E4orf6 facilitated export of more viral late mRNAs. • The results partially explained the reason why HAdV-41 was fastidious in 293 cells.