GATA-1 down-regulates the myeloid phenotype without repressing PU.1 gene expression.

HD50M myeloblasts containing a GATA-1–estrogen receptor (GER) fusion (right panels) as well as control myeloblasts (left panels) were treated with 1 μM of β-estradiol or left untreated, as indicated. Total RNA was extracted from cells at the indicated time points, and 10-μg aliquots were subjected to Northern blot analysis. The blot was probed sequentially with probes for chicken MHC class II γ chain and β-actin.