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

Abstract

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-17fl. 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. the end of the incubation period, the two groups of uteri were pooled, rinsed thoroughly with ice-cold 0.9% NaCl, and rapidly frozen on dry ice. Under these conditions the incorporation of labeled amino acids into uterine protein was linear for incubation periods of at least 3 hr.Cell Fractionation. Uterine chromatin was prepared by a modification of the method of Bonner et al. (10). All procedures were carried out at 0-40 unless otherwise indicated. Frozen uteri were placed in a stainless steel tissue pulverizer chilled to -80°and crushed to a powder. The frozen powder was homogenized in 20 ml of saline-EDTA (0.075 M NaCl, 0.025 M EDTA, pH 8) with a polytron PT 20 tissue disintegrator run at 60 V for 30 sec, and the homogenate was filtered through four layers of nylon bolting cloth. A pellet was collected by centrifugation at 1500 X g for 15 min in the Sorvall RC-2 centrifuge. The pellet was washed once with the saline-EDTA containing 0.5% Triton X-100, and then once with the saline-EDTA alone. It was then washed three times with 0.01 M Tris-HCl (pH 8) by centrifugation at 4300 X g, 10,000 X g, and 17,000 X g. The

Radiolabelled rat uterine luminal proteins and their regulation by oestradiol and progesterone

“…The template activity of uterine chromatin which is high on Day 5 of preg¬ nancy and at oestrus (O'Grady et al, 1975) is enhanced by oestradiol and progesterone (Teng & Hamilton, 1968;Glasser & Clark, 1975 , and specific nonhistone chromosomal proteins, which may be important for gene transcription, are detected in uterine cells (Cohen & Hamilton, 1975). New species of nuclear RNA have been found on Day 5 of pregnancy in the rat (Heald & O'Hare, 1973).…”

“…New species of nuclear RNA have been found on Day 5 of pregnancy in the rat (Heald & O'Hare, 1973). Hitherto, consideration has mainly been of the early production of a few cytoplasmic proteins, such as the induced protein (Gorski, 1973;Somjen, Somjen, King, Kaye & Lindner, 1973) postulated to bind to the chromatin to bring about further changes in gene expression (see Cohen & Hamilton, 1975). Generalized increase in protein synthesis during cytodifferentiation has not been considered in detail, but some of the luminal proteins may be secretory products of differentiated cells, although the cell types from which they originate remain to be established.…”

Uterine luminal proteins at the time of implantation in rats

“…The increased protein content in the lumen during pregnancy may be due, at least in part, to the secretion of uterine-specific proteins. Oestradiol is known to cause the synthesis of nonhistone chromosomal proteins in the uterus (Cohen & Hamilton, 1975) (Yochim, 1975).…”

The Action of Growth and Developmental Hormones

“…It has been suggested that conformational changes in chromosomal organization that facilitate gene transcription may be mediated via redistribution or modification of histones or nonhistone chromosomal proteins (Cohen and Hamilton, 1975;Kleinsmith, 1975;Stein and Kleinsmith, 1975;see Bradbury and Javaherian, 1977;Chiu and Hnilica, 1977;Mathis et at., 1980;Igo-Kemenes et at., 1982;Weisbrod, 1982). Thus, posttranslational modifications of histones, such as phosphorylation, acetylation, and ADP-ribosylation, appear to accompany changes in the nucleosomal organization of chromatin and alterations in its template activity, including those induced by some hormones (Libby, 1973;Allfrey, 1977;Davie and Candido, 1978;Johnson and Allfrey, 1978;Mathis et at., 1978Mathis et at., , 1980Vidali et at., 1978;Samuels et at., 1980).…”