The genomically integrated SMT3-S-eL40A-HA allele permits better growth than the corresponding ubi1∆ub-HA allele. Growth analysis of the indicated strains, either expressing a C-terminally HA-tagged Ubi1 (UBI1-HA) or a Smt3-S-eL40A (SMT3-S-eL40A-HA) fusion variant protein from the UBI1 genomic locus or from a centromeric plasmid (+ SMT3-S-eL40A-HA) in a wild-type UBI2 or a ubi2∆ null mutant background. Strains W303-1A (Wild type), SMY218 (SMT3-S-eL40A-HA), SMY258 (SMT3-eL40A-HA ubi2∆), SMY256 (UBI1-HA ubi2∆), SMY257 (ubi1∆ub-HA ubi2∆), SMY216 [YCplac111-SMT3-S-eL40A-HA] (ubi1∆ ubi2∆ + SMT3-S-eL40A-HA), and JDY923 (ubi2∆) were spotted in fivefold serial dilution steps onto YPD plates, which were incubated for 4 days at 22 °C and for 3 days at 30 °C and 37 °C.