(O) YY1iKO ASCs were transfected with empty YY1 WT viruses; the relative expression level of Hif1a protein was detected by the above described flow cytometric analysis N=3 mice. 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. 