Effect of extradiol-17beta on the synthesis of specific uterine nonhistone chromosomal proteins.

The synthesis of specific nonhistone chromosomal proteins in the uterus of the ovariectomized rat was examined as a function of time after treatment with estradiol-17beta. Sequential stimulations in the rates of synthesis of at least five nonhistone chromosomal proteins having molecular weights of 96,000, 70,500, 29,400, 20,700, and 16,400, respectively, were observed. The rate of synthesis of the nonhistone chromosomal protein having a molecular weight of 70,500 was increased at 1 hr after hormone treatment. This was the first nonhistone chromosomal protein to be induced by estrogen, and its induction was blocked by pretreatment with actinomycin D. The data reported suggest but do not prove that this protein is the 4.5 S estrogen receptor, and that it is the induced nuclear acidic protein described earlier by Teng and Hamilton. The rates of synthesis of the nonhistone proteins with molecular weights of 96,000, 29,400, 20,700, and 16,400 were increased at 3,5,24, and 24 hr, respectively, after hormone treatment.