SIRT1 overexpression partially restores the transcriptional repression within specific loci in sir2Δ mutant.

<div><p>RT-PCR transcriptional analysis in WT and <i>sir2Δ</i> strains transformed with empty plasmid (-), <i>SIRT1</i> construct (+) or <i>SIRT1</i>-<i>H363Y</i> mutant construct (+*) both in repression (glucose) and induction (galactose) conditions. (A) rDNA locus: <i>NTS1r</i> and <i>NTS2</i>; (B) TEL VI locus: <i>YFR057W</i> and <i>IRC7</i>; (C) HM loci: <i>HMLalpha1</i>. Histograms indicate averages and Std. Dev. bars from at least three independent biological replicates. Two−tailed t−test was applied for statistical analysis. Asterisks indicate statistically significant differences between <i>sir2Δ</i>- and <i>sir2Δ</i>+ or between <i>sir2Δ</i>+* and <i>sir2Δ</i>+ in galactose medium; α = 0.05. (Percentages of p−value: *p< 5%, **p < 1%, ***p < 0.01%).</p> <p>(D) Alpha factor yeast spot test analysis to evaluate <i>HMLalpha1</i> silencing. Five-fold serial dilutions of mutant <i>sir2Δ</i> and WT cells transformed with <i>SIRT1</i>(+) or empty plasmid (−) were spotted onto minimal medium plates containing alpha-factor.</p>