highly significantp < 10 −144
Using MSigDB to perform gene set enrichment analysis 26 , 27 , we found a highly significant enrichment for binding sites in the Sp1/Krüppel-like factor family 28 ( p < 10 −144 by Bonferroni-corrected hypergeometric test) and for genes downregulated in Klf1 −/− cells ( p < 10 −57 ).