The promyelocytic leukemia zinc finger (PLZF) protein binds DNA in a high molecular weight complex associated with cdc2 kinase

A binding site selection from a CpG island library for the promyelocytic leukemia zinc finger protein (PLZF) identified two high affinity PLZF binding sites. These sequences also bound RAR alpha/PLZF, a fusion protein formed in chromosomal translocation t(11;17)(q23;q21) associated with acute promyelocytic leukemia. PLZF bound DNA as a slowly migrating complex with an estimated mel. wt of 600 kDa whose formation was dependent on the POZ/dimerization domain of PLZF, The PLZF-DNA complex was unable to form in the presence of cdc2 antibodies. A PLZF-cdc2 interaction was further demonstrated by co-immunoprecipitation and a biotin-streptavidin pull-down assay. PLZF is a phosphoprotein and immunoprecipitates with a cdc2-like kinase activity. The PLZF-DNA complex was abolished with the addition of a phosphatase, These studies suggest that the activity of PLZF, a regulator of the cell cycle, may be modulated by cell cycle proteins. RAR alpha/PLZF did not complex with cdc2, this potentially contributing to its aberrant transcriptional properties and potential role in leukemogenesis.