Age-dependent gene induction in quail oviduct. IX. Age-dependent alterations of DNA-bound amino acids

DNA-amino acids (and DNA-protein) complexes were isolated from oviducts of immature, mature and senescent quails by a procedure which does not involve proteolytic enzymes. The content of DNA-amino acids in the complexes, isolated from animals belonging to three different age classes is almost identical and it amounts to about 10 micrograms/mg DNA. However, the fraction of DNA-amino acids which is resistant to pronase is twice as high in lysates from senescent quails as in those from immature and mature animals. The amount of DNA-bound amino acids is strongly dependent on hormone-induced physiological effects in immature quails. If immature animals were treated with estrogen hormone, which causes in induction both of DNA and RNA synthesis, the level of DNA-bound amino acids increases by 220%. This material has been found to be pronase sensitive which might indicate that the amino acids are present as peptides. Treatment of estrogen-stimulated animals with progesterone or inhibitors of DNA and RNA synthesis antagonizes the estrogen-envoked formation of DNA-associated amino acids. From the data we propose that the amount of proteins and/or amino acids, bound to DNA,is not only age-related but also correlated with the physiological state of DNA in immature and mature animals.