The adenovirus L4 100-kilodalton protein is necessary for efficient translation of viral late mRNA species

摘要: Abstract When screening a number of adenovirus type 5 (Ad5) temperature-sensitive mutants for defects in viral gene expression, we observed that H5ts1-infected 293 cells accumulated reduced levels newly synthesized late proteins. Pulse-labeling and pulse-chase experiments were used to establish the proteins under nonpermissive conditions as stable those made Ad5-infected cells. contained normal mRNAs. Because these observations implied translation mRNA species was defective mutant virus-infected cells, association mRNAs with polyribosomes examined during phase infection at temperature. In majority L2, L3, L4, pIX, IVa2 polyribosome bound. By contrast, same recovered from fractions nearer top gradients, suggesting initiation impaired. During infection, neither nor most early affected by H5ts1 mutation. This lesion, mapped marker rescue L4 100-kilodalton (kDa) nonstructural protein, has been identified single base pair substitution replaces Ser-466 Ad5 100-kDa protein Pro. A set temperature-independent revertants isolated characterized. Either true reversion mutation or second-site Pro-466 Thre, Leu, His restored both growth efficient synthesis We therefore conclude is necessary infection.