Sirt1 directly binds to the Hoxa9 locus and facilitates a repressive chromatin environment. ChIP analysis of 4F BM cultures. (A–C) Total cultures (B and D) or sorted c-Kit⁺Sca-1⁺ cells (A and C) were subjected to ChIP with the indicated antibodies. Enrichment over input is shown. Primer set locations are indicated, and values represent mean of triplicates. (D) Sirt1 ChIP at the indicated Hox loci. Enrichment over input is shown relative to the Hoxb8 locus. Error bars represent SD. *, P ≤ 0.05; **, P ≤ 0.01.