DYNAMICS OF PROTEIN-KINASE CK2 ASSOCIATION WITH NUCLEOSOMES IN RELATION TO TRANSCRIPTIONAL ACTIVITY

Protein kinase CK2 has been implicated in control of cell growth and p roliferation. Since growth stimuli evoke its preferential association with chromatin and nuclear matrix, we examined the dynamics of CK2 in nucleosomes fractionated on the basis of their transcriptional activit y in the rat prostate. In this model, androgens induce expression of a ndrogen-dependent genes but inhibit the androgen-repressed genes, wher eas absence of androgens has the reverse effect. The level of CK2 was higher in the active than in inactive nucleosomes from normal prostate . Differential alterations in the levels of CK2 activity in the transc riptionally active versus inactive nucleosomes were evoked by androgen deprivation or administration. Comparison of the distribution of CK2 in active and inactive nucleosomes under varying androgenic conditions showed that the relative CK2 activity intrinsic to the transcriptiona lly active nucleosomes remained fairly stable, concordant with gene ac tivity specific to the androgenic status. However, CK2 associated with inactive nucleosomes declined to a minimal level on androgen deprivat ion but increased rapidly on androgen administration (reflecting expre ssion of multiple androgen-dependent genes). We suggest a role for CK2 in promoting the conformational transition of inactive nucleosomes to the active form and in the function of transcriptionally active nucle osomes.