Enforced expression of

CUL-4A inhibits macrophage differentiation. The cell lines generated from PLB-985 cells transfected with pEF-PGKpac (empty vector) or with pEFpac-CUL-4A-HA (CUL-4A-HA2) were induced to differentiate into macrophages with 100 nM PMA for 0 to 3 days, and total RNA was isolated from a sample taken at each time point. RNA (5 μg) from each sample was electrophoresed, and the amount of gp91^phoxmRNA was determined by Northern blot analysis and normalized with respect to the amount of actin mRNA.