The guanine nucleotide exchange factor GBF1 participates in rotavirus replication

José L. Martínez; Francesca Arnoldi; Elisabeth M. Schraner; Catherine Eichwald; Daniela Silva-Ayala; Eunjoo Lee; Elizabeth Sztul; Óscar R. Burrone; Susana López; Carlos F. Arias

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/619924 doi: bioRxiv preprint 7 impaired the yield of viral progeny through a block in the assembly of the virus surface 128 proteins, VP7 and VP4, which prevents the production of mature and infectious TLPs. We 129 also showed that this restriction in the assembly of TLPs is the result of a damage in VP7 130 trimerization required for its assembly into DLPs. We provide evidence suggesting that an 131 altered post-translational modification (different from glycosylation) of either VP7 or NSP4 132 in GBF1-inactivated cells is responsible for the defective formation of VP7 trimers. 133 Altogether, our findings suggest that GBF1 activity is essential for the rotavirus outer capsid 134 assembly by allowing the correct processing of VP7 and/or NSP4, possibly through a 135 mechanism independent of Arf1. was then added to cells in the presence of the inhibitors for 1 h at 37°C. Then, the virus 144 inoculum was removed, and fresh media containing the inhibitors were added; 12 h post 145 infection (hpi), cells were harvested, and the viral yield was determined. We found that 146 treatment with BFA (at a concentration of 0.5 μg/ml or higher) reduced by more than 100-147 fold the viral yield ( Fig 1A) ; this observation is in agreement with a previous report (21).