SUMO1 and infection: To confirm these data, and to determine if loss of hSpt16SUMO levels during VSV-eGFP infection was not due to a global down regulation of intracellular SUMOylation, we used Ab against SUMO-1 or SUMO-2/3 to immunoprecipitate (IP) SUMOylated protein fractions from mock-, VSV-eGFP-, or VSVM51R-eGFP-infected WCE [6].