6533b7ddfe1ef96bd12735b5

RESEARCH PRODUCT

Alteration of poly (ADP-Rib) synthesis during progesterone- caused gene expression in oviducts of quails.

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Summary The biological model of the selective induction of RNA synthesis in oviducts of estrogen stimulated immature quails by progesterone has been used to clarify whether poly (ADP-Rib) is involved in DNA transcription. The chromatin-bound as well as the soluble poly (ADP-Rib) polymerase has been isolated from oviducts and the optimal reaction conditions have been determined. The activities, as measured by the incorporation rates of NAD + into poly (ADP-Rib), of both, chromatin-bound « endogenouspolymerase (in the absence of « exogenousDNA and histones) and soluble enzyme (native DNA - lysine-rich histone ratio: 4.3) from progesterone treated quail oviducts, have been determined to be only 30 per cent and 46 per cent respectively, as compared with the activities of the enzymes from the controls. This decrease in incorporation rates is apparently not due to an increased poly (ADP-Rib) degrading enzyme activity. Poly (ADP-Rib) synthesis in vivo was determined by incorporation studies with the precursor [ 14 C] ribose. 12 hr after intraperitoneal administration, 0.014 per cent of the total radioactivity was recovered in the oviduct histone fraction, 0.011 per cent in the oviduct nonhistone fraction and 0.009 per cent in the oviduct « HCl-extractcontaining the histone subfractions f1, f2 and f3. Among these histone subfractions, f1 is ADP-ribosylated to the largest extent. ADP-ribosylation of f1 is less extensive in progesterone-stimulated oviducts (65 per cent) than in the controls (100 per cent). The present results suggest that in course of the selective, progesterone-induced DNA transcription the poly (ADP-Rib) synthesis might drop.