HMGB2 increases Oct-1 binding to the GFI1B promoter in vitro and in vivo. (A) GATA-1, Oct-1, NF-YA, and HMGB2 binding to the GFI1B promoter in vitro in the presence or absence of HMGB2. Oligonucleotide corresponding to site 1 or site 2 of the GFI1B promoter was incubated with cell lysates from erythroid UT-7 cells. The GATA site of the site 1 and the 3 Gfi-1/Gfi-1B–binding sites of the site 2 oligonucleotides (that bind GATA-1) were mutated when indicated. Cell lysates from UT7 cells infected with shControl or shHMGB2 lentiviruses were used. Total cell extracts were shown (input). Results are representative of 3 independent experiments. (B) In vivo binding of HMGB2, Oct-1, NF-YA, and GATA-1 to the GFI1B promoter. ChIP analyses were performed with chromatin from undifferentiated shControl- or shHMGB2-transduced UT-7 cells using antibodies against HMGB2, Oct-1, NF-YA, or GATA-1. Quantitative PCRs were performed with 2 pairs of primers, one amplifying a sequence within the GFI1B promoter (−0.15 kb) and the other one amplifying the β₂microglobulin promoter. Results are expressed as enrichment values (bound/input) relative to IP with IgG antibody and are means ± SD of 3 independent ChIP experiments; *P < .05 by Student t test.