Feedback inhibition modulates HDAC activity. Two genes were identified
as potential modulators of RPD3- and
SIR2-mediated repression: the zinc transporter gene,
ZRT1, is repressed by the zinc-dependent HDAC, Rpd3p;
the NAD-biosynthesis gene, BNA1, is repressed by the
NAD-dependent HDAC, Sir2p (12) (B.E.B. and S.L.S., unpublished
results). Interestingly, RPD3 activates
BNA1, and SIR2 appears to activate
ZRT1. The particular acetylation pattern induced by
these HDACs may, in certain cases, activate transcription (see text and
Fig. 5). Fold changes induced by RPD3 deletion, SIR2
deletion, and by 15 min and 30 min TSA treatments are shown.