Figure 1

Endogenous Hsp16 is responsive to vpr gene expression. (A) Expression of hsp16 was measured through GFP green fluorescence as shown by gfp-hsp16 fusion protein expression. Cells were grown under normal growth conditions and expression of the wild type vpr (Vpr) or mutant F34I vpr (Vpr’) was induced in thiamine depleted EMM medium as previously described [35]. Photographs were taken 24 hrs after gene induction. Small panel in A-a shows cells without green fluorescence. (B) Comparison of the Hsp16 protein levels in the presence and absence of Vpr as shown by Western blot analysis. The vpr or vpr’-expressing cells were collected at the same time as in panel (A). Lane 1 shows wild type SP223 cells without plasmid; lanes 2 and 4 show cells with vpr gene expression repressed; lanes 3 and 5 – cells with vpr gene expression induced. Note that elevation of Hsp16 shown in lane 2 is most likely due to leakage of nmt1promoter and low level gene expression under these conditions [36]. LC, protein loading control. A protein band that nonspecifically reacted to the antibody was used as a protein loading control. GI, gene induction.