(S) A construct to express wild type YY1(WT), or two mutants lacking DNA binding activity, YY1(1-394) and YY1(S365D) were transfected into YY1iKO cells; the expression of mitochondrial gene was measured. Error bars represent s.d.'s of the mean. Student's t-test (two-sided): N.S = non-significant, *P<0.05, **P<0.01, ***P<0.001. 