Among the mutants tested were a type III secretion mutant (pscD), mutants in three different type III virulence effectors (ExoT, ExoU, and ExoY), an exoTUY triple mutant, a mutant in a secreted exotoxin (toxA), and two mutants in a gene involved in the production of toxic hydrogen cyanide (hcnC).
To determine if NBR1 needs to be primed for GSK3 phosphorylation, we performed kinase assays with the GSK3B R96A mutant, a mutant that is unable to phosphorylate primed substrates but remains capable of phosphorylation of unprimed substrates.
Interestingly, the ability of the lasA mutant, a mutant strain deficient in the production of the staphylolytic LasA protease (12), to provide a synergy with TO against S. aureus was also impaired (Fig. 2B).
Additionally, three mutant model systems were constructed based on the native model: a mutant lacking the β-hairpin (Δ233 240) (sim2, hairpin mutant), a mutant lacking the α-helix (Δ447 460) (sim3, helix mutant), and a mutant lacking both (Δ233 240 and Δ447 460) (sim4, helix-hairpin mutant).
To test whether land plant SIG1 proteins generally regulate the expression of these three genes, their transcript levels were analyzed in an Ossig1 mutant (a mutant with an insertion of the retrotransposon Tos17 at the OsSIG1 locus: NE8184) by qRT-PCR analysis (fig. 6).
