Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The artificially stimulated decidual cell reaction has been used as a model to study changes occurring in the uterus at the time of implantation. Activities of RNA polymerases I, II and III were measured in uterine nuclei isolated from ovariectomized non-primed mice, hormonally primed mice, and hormonally primed mice following stimulation of the decidual cell reaction. Activities of all three RNA polymerases increased following hormonal priming of ovariectomized mice. In nuclei from stimulated uterine horns, activities of RNA polymerases I and III increased 9 h after stimulation of the decidual cell reaction and remained elevated through 21 h. RNA polymerase II activity did not change following stimulation of the decidual cell reaction. These changes in RNA polymerase activities occur at the time of increased histone modifications and may result from changes in the template capacity.
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PMID:Changes in RNA polymerase activity in isolated mouse uterine nuclei during the decidual cell reaction. 71 31

The role of steroid receptors in the early events of progesterone action was elucidated by examining the temporal relationship between the nuclear accumulation of progestin receptor and changes in activities of RNA polymerases I and II, as well as that of chromatin template in rabbit uterus. Following a 5-day estrogen pretreatment, the animals received an intravenous injection of progesterone (10 mg), after which they were killed at timed intervals. Nuclear progestin receptor level, as measured by an exchange assay, reached the peak value 30 min after hormone administration (11 600 to 46 600 sites/nucleus) and declined to the control levels by 4 h. Changes in the activities of RNA polymerase I and II did not follow identical time courses: polymerase I rose at 30 min and remained elevated for 2 h and then declined to about 75% of the pretreatment activity, whereas RNA polymerase II activity increased more rapidly (at 15 min), and was followed by a sharp decrease to about 50% of the initial value. Thereafter, the latter enzyme activity rose slowly and reached the pretreatment level within 12 h of progesterone administration. Early changes in chromatin template activity were similar to those in RNA polymerase I with a second rise by 8--10 h. The early inhibition of transcriptional events by progesterone may result from antiestrogenic properties of this steroid. Accumulation of nuclear progestin receptor occurs at a similar time to early changes in the transcriptional events suggesting a regulatory role for the hormone receptor complexes.
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PMID:Progesterone-regulated changes in transcriptional events in rabbit uterus. 92 5

We have shown previously that estradiol, estriol, and Nafoxidine (Upjohn 11, 100A) have differential effects on uterine growth and that these effects are associated with the retention of the estrogen receptor by the nucleus. In order to examine these relationships further, we have studied the effect of these hormones on endogenous nuclear RNA polymerase I and II in the immature rat uterus. All three compounds caused a rapid elevation in polymerase II activity that reached a peak by the first hour and declined to almost control levels by 2 h after the injection. This transient peak in polymerase II activity was followed by a second elevation by the fourth hour in estradiol- and Nafoxidine-treated animals which was not observed in estriol-treated rats. The activity of polymerase I increased monotonically to very high levels by 4 h and was maintained 12 h or longer in estradiol- and Nafoxidine-treated animals. A similar elevation was observed in estriol-treated rats but the activity declined very rapidly to control levels by 12 h. The second elevation in polymerase II activity and the sustained stimulation of polymerase I activity were correlated with the stimulation of true uterine growth. These data confirm our previous suggestion that long-term nuclear retention of the receptor is a requirement for true uterine growth and suggest that an obligatory response in the production of true growth is the stimulation of a second rise in polymerase II activity and an elevated and sustained activity of polymerase I.
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PMID:RNA polymerase activity and uterine growth: Differential stimulation by estradiol, estriol, and nafoxidine. 94 48

DNA-dependent RNA polymerases of immature and castrated rat uteri were studied after estradiol administration. The enzymes were solubilized from either whole uterus homogenate or nuclei and their activities were measured on an exogenous DNA template. alpha-Amanitin was used to distinguish alpha-amanitin-resistant from alpha-amanitin-senitive forms of the enzyme. The number of alpha-amanitin-sensitive RNA polymerase molecules was measured by a binding assay using labeled amanitin. In the first series of experiments RNA polymerases were solubilized from whole uterus homogenate. alpha-Amanitin-sensitive and -resistant activities were constant during the first 6 hours after estradiol treatment, followed by a late and moderate increase in their activities (50% at 12 hours for the resistant form and 40% at 24 hours for the sensitive form). The number of sensitive polymerase molecules evolved in an identical manner to its activity (+40% at 24 hours), suggesting that the increase in activity is due to the synthesis of new enzyme molecules. For both forms, no diffusible stimulatory factor was detected in the uterus of hormone-treated animals. In the second series of experiments, disrupted nuclei were washed with 0.15 M (NH4)2SO4 in order to release only enzyme molecules which were not firmly bound to DNA in a transcription complex. The amount of the sensitive form of polymerase which remains firmly bound to chromatin, was constant for 6 hours after estradiol administration and was doubled by 24 hours. The firmly bound alpha-amanitin-resistant activity was solubilized and was measured in the presence of an exogenous template. There was a progressive increase in activity first detectable in 1 to 2 hours, amounting to 50% at 6 hours and 100% at 24 hours. The reported results show that during the first 6 hours of hormone treatment: (a) the total content of RNA polymerases remains unchanged in the uterus; (b) the number of alpha-amanitin resistant molecules tightly bound to DNA increases progressively while the alpha-amanitin sensitive remains constant. At a later time (24 hours), an increase is observed both for the total amount of enzymes and for their fraction engaged in a transcription complex.
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PMID:Effect of estradiol on rat uterus DNA-dependent RNA polymerases. Studies on solubilized enzymes. 95 66

1. The template activity of chromatin prepared from rat uterine nuclei during dioestrus, oestrus and the first 7 days of pregnancy has been examined. 2. The DNA, RNA, histone and non-histone protein contents of uterine chromatin remained constant during early pregnancy. 3. The rate of RNA synthesis on Day 1 uterine chromatin was 8.61 +/- 0.59 (mean +/- S.E.) pmol of UMP incorporated/mg DNA per 10 min. When compared with DNA prepared from rat liver nuclei, 13.20 +/- 0.27% (mean +/- S.E.) of the Day 1 chromatin DNA was available for transcription by Escherichia coli RNA polymerase. 4. Uterine chromatin from rats in early dioestrus had significantly less template activity than during oestrus. 5. Chromatin prepared from whole uterus on Day 5 and from implantation sites on Days 6 and 7 of pregnancy had a significantly higher template activity than chromatin obtained from uteri on Day 1. Chromatin from interimplantation tissue on Day 6 had a lower template activity than that from uteri on Day 1. 6. RNA - DNA hybridisation of RNA transcribed from chromatin obtained on Days 2, 5 and 7 of pregnancy showed that RNA transcribed from Day 5 chromatin obtained species not present (or present in very small amounts) in RNA transcribed by chromatin from uteri on Day 2 and from implantation tissue on Day 7 of pregnancy. 7. The results are discussed in relation to the cellular changes occurring in the stroma immediately before implantation and it is postulated that the appearance of a new species of RNA on Day 5 is related to the preparation of the stromal cells for decidualisation.
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PMID:Uterine chromatin template activity during the early stages of pregnancy in the rat. 118 77

Two clones have been selected from a human fibroblast cDNA bank. By DNA sequencing the clones were shown to contain Alu elements located near the ends of the cDNA inserts. DNA of the clones was used for Northern blot hybridization analysis of a number of poly(A)-containing RNAs from normal human tissues (brain, stomach, uterus, spleen, fibroblasts) and tumors (neurinoma, glioma, neuroblastoma, liposarcoma, adrenal cortex adenocarcinoma). All RNA samples reveal a heterodisperse distribution of Alu transcripts with discrete bands in the region of 7-12 S RNA. The majority of these small poly(A)+ Alu+ RNAs contain Alu sequences only in one (canonical) orientation with functional signals including the split promoter for RNA polymerase III.
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PMID:Cloning of Alu-containing cDNAs from human fibroblasts and identification of small Alu+ poly(A)+ RNAs in a variety of human normal and tumor cells. 243 58

The estrogen stimulated rat uterus serves as a useful model to examine steroid resistance during aging. This system exhibits receptor loss, impaired stimulation of RNA polymerase II and defects in nuclear translocation (or enhanced association) of receptor-estradiol complexes. All of these defects appear to contribute in part to decreased estrogen responsiveness of the senescent rodent uterus.
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PMID:Altered estrogen action in the senescent rat uterus: a model for steroid resistance during aging. 352 Dec 24

We transcribed a cDNA clone of the human estrogen receptor (ER) with T7 RNA polymerase. The 32P-cRNA transcript complementary to ER mRNA was hybridized to poly(A)+ RNA from human uterus and revealed a single band of approximately 4.2 kilobases. No hybridization was seen with the cRNA probe of the opposite orientation. Hybridization of total RNA from calf and rat uterus yielded a single band at approximately 3.8 kilobases for both species. Total RNA from rat spleen did not hybridize. A 35S-labeled cRNA probe was prepared for in situ hybridization of ER mRNA in human uterus and spleen. Autoradiographic signal was present over endometrial epithelium, stromal cells of the lamina propria, and smooth muscle cells of the myometrium but was absent from sections of spleen. The ER mRNA hybridization label was located over cytoplasm and nuclei of uterine target cells.
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PMID:Detection of estrogen receptor mRNA in human uterus. 365 5

1. Labelled testosterone, injected directly into the ventral prostate of castrated rats became associated, in part, with a cytoplasmic high-molecular-weight fraction, fraction ;A'. 2. The label present in fraction ;A' was found to be mainly associated with dihydrotestosterone. 3. Unlike fraction ;A' from testosterone-pelleted castrated rats, fraction ;A' obtained from untreated castrated rats, 48h or more after castration, was strongly inhibitory towards Escherichia coli RNA polymerase in vitro. 4. The inhibition of RNA polymerase by fraction ;A' from castrated rats was not changed by the addition of testosterone or dihydrotestosterone in vitro, but pre-heating it to 80 degrees C resulted in a loss of its inhibitory capacity. 5. Fraction ;A' from castrated rats contained ribonuclease activity. The elution profile of ribonuclease activity from Sephadex columns indicated that this activity was responsible for the inhibitory effect on the RNA polymerase assays. 6. It is concluded that, unlike the inhibitor present in the uterus of ovariectomized rats (Talwar, Segal, Evans & Davidson, 1964), no direct connexion exists between the steroid-binding capacity of prostatic fraction ;A' and its effect on E. coli RNA polymerase activity in vitro.
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PMID:Some effects of testosterone on the rat ventral prostate. 424 60

1. Additional evidence was obtained that the nuclear oestradiol-17beta receptor is an acidic protein. Partial purification of the receptor protein was obtained by chromatography on hydroxyapatite and it contains protein-bound phosphate. 2. The nuclear ;5s' and cytoplasmic ;9.5s' and ;5s' receptors from uterus, dimethylbenzanthracene-induced mammary adenocarcinoma and kidney are precipitated together with bound oestradiol-17beta by protamine sulphate. This common property suggests that the nuclear and cytoplasmic receptors are related to each other. 3. The properties of two acidic protein fractions from both liver and dimethylbenzanthracene-induced mammary adenocarcinoma are described. Fraction 1 contains two major components and fraction 2 contains one component, as judged from polyacrylamide-gel electrophoresis. Fraction 2 contains RNA and both fractions contain protein-bound phosphate. 4. These fractions form insoluble complexes with calf thymus histone, protamine sulphate and poly-l-lysine. The formation of these complexes is markedly affected by ionic strength and pH. Ionization of both the in-amino group of lysine and carboxyl group are involved. RNA and DNA do not appear to be involved. The interaction is not affected by EDTA or 1mm-Na(+), -K(+), -Ca(2+), -Mg(2+) or -Mn(2+). Per unit weight, whole histone has 4-5 times as many binding sites for the acidic proteins as the latter have for the former. 5. No convincing evidence was obtained for DNA-acidic protein interaction, but, as judged from precipitation experiments, there was competition between DNA and acidic protein for histone. 6. Relatively large amounts of acidic protein partly relieved the histone inhibition of the template activity of DNA for Escherichia coli RNA polymerase (EC 2.7.7.6).
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PMID:The properties of a nuclear acidic protein fraction that binds [6,7-3H]oestradiol-17beta. 489 41


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